Annual Review 2003

Nuclear Waste Management of theOlkiluoto and Loviisa Power Plants

The front cover shows a split copper canister billet, with its crystal structure in view.

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SUMMARY

This report describes the nuclear wastemanagement of the Olkiluoto and Lo-viisa nuclear power plants. The reportincludes a description of the status andoperations of nuclear waste managementof the power companies in 2003, a re-view of the communication activitiespertaining to nuclear waste manage-ment, and an account of the provisionsmade for future waste managementcosts.

The Ministry of Trade and Industryrevised the schedule for the final dis-posal of spent fuel in such a way that, inaccordance with the new schedule, thematerial required to apply for a con-struction licence must be ready by theend of 2012. At the same time, the Min-istry set a new intermediate target at2009, at which time an overview of thematerial intended for the application fora construction licence must be submit-ted. On the whole, preparations for thefinal disposal of spent fuel progress inaccordance with the programme for thepre-construction phase of the final dis-posal facility published in 2000. Thefirst three-year programme “TKS-2003”pertaining to research, development andtechnical design was drawn up duringthe year under review. The report alsoincluded a survey of the results of thework done during the past 3–4 years.

With regard to bedrock investiga-tions at Olkiluoto, the main emphasiswas on studies into the area of accessand alignment of the access tunnel tothe underground rock characterisationfacility known as ONKALO. Extensiveinvestigations into bedrock structuresand the baseline at Olkiluoto continued,employing various methods and, at thesame time, provision was made for mon-itoring ONKALO during constructionand operation.

In the assessment of long-term safe-ty, the proportion of international co-operation projects remained high. Sev-

eral projects with a view to studying theperformance of engineered barriers,implemented within the scope of theEU’s fifth framework programme, arein the phase of final reporting. With re-spect to bedrock, the studies pertainedto the migration and retention phenom-ena, and their modelling. In biospherestudies, the development of modellingcontinued.

The first plant description of theentire final disposal facility that takesthe infrastructure and environmentalconditions at Olkiluoto into account wascompleted during the year under review.Furthermore, the description took pre-liminarily account of the impact of thethird plant unit at Olkiluoto (OL3) onfinal disposal.

In the design of the final disposalcanister, Posiva’s and SKB’s plans wereharmonised and drafting of a canistersuitable for the OL3 fuel began. Withregard to canister manufacturing tech-nology, one of the principal develop-ment subjects continued to be the man-ufacture of the cylindrical part of thecopper canister from one piece, withseveral optional methods. In the devel-opment work on canister sealing tech-nology, an agreement was reachedwhich enables future test programmesto be mostly implemented in Finland.Detailed design of the main equipmentof the encapsulation plant continued.With respect to canister transportation,studies focused on the consequences ofan accident where the lift falls with acanister in the transport shaft.

In designing the repository, the pri-orities included developing the low-pHgrouting material, the horizontal dispos-al concept and the backfilling methods,and co-ordinating the design of the re-pository and the ONKALO facility.

The main drawing stage plan for theONKALO facility and four other reportslinked with the implementation of

ONKALO were submitted to STUKRadiation and Nuclear Safety Authori-ty for consideration. The municipalityof Eurajoki granted a building permitin accordance with the Building Act forONKALO on 12 August 2003 and theinvitations for tenders for the first tun-nel contract were sent to the excavationcontractors in November. Area workabove ground began towards the end ofthe year.

In international co-operation, themost significant projects were imple-mented, on the one hand, within theframework of the extensive agreementssigned with SKB in 2001 and, on theother hand, within the scope of the EU’sfifth framework programme. Three re-search projects under the EU’s sixthframework programme progressed tothe agreement phase. Posiva signed anagreement in principle on co-operationwith the United States’ Department ofthe Environment (DOE).

With regard to operating waste, theestablished monitoring and long-terminvestigations and practical measurescontinued.

By the end of 2003, 4 335 m3 ofoperating waste had accumulated at theOlkiluoto Power Plant, and 2 685 m3 atLoviisa; 3 918 m3 of the Olkiluoto wastehas been finally disposed of in the VLJRepository; 1 180 m3 of the Loviisawaste has been disposed of in the low-and intermediate-level waste reposito-ry at Hästholmen.

The decommissioning plans for thepower plants were updated by the endof 2003.

The overall costs of the researchprogramme for nuclear waste manage-ment of the Loviisa and Olkiluoto Pow-er Plants amounted to EUR 13.1 mil-lion. On the whole, the research pro-gramme was implemented according toplan.

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CONTENTS

Page

SUMMARY 1

INTRODUCTION 5

SPENT FUEL MANAGEMENT 6• PRINCIPLES AND SCHEDULE 6• CURRENT STATUS OF STORAGE 6• FINAL DISPOSAL PROJECT 7• ASSESSMENT OF LONG-TERM SAFETY 10• FINAL DISPOSAL TECHNOLOGY 14• DESIGN AND CONSTRUCTION OF THE ONKALO FACILITY 21• INTERNATIONAL CO-OPERATION 22

MANAGEMENT OF OPERATING WASTE 24• OLKILUOTO POWER PLANT 24• LOVIISA POWER PLANT 26• JOINT STUDIES 28

DECOMMISSIONING INVESTIGATIONS 29• OLKILUOTO POWER PLANT 29• LOVIISA POWER PLANT 29• JOINT STUDIES 30

REPORTING, COMMUNICATIONS AND CONTACTS 31

CO-OPERATION PARTNERS 32

QUALITY MANAGEMENT AND ENVIRONMENTALMANAGEMENT 33

COSTS 34

LIST OF REPORTS 2003 35

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INTRODUCTION

In Finland, two companies utilise nucle-ar energy to generate electrical power –Teollisuuden Voima Oy (TVO) and For-tum Power and Heat Oy (hereafter re-ferred to as Fortum). In compliance withthe Nuclear Energy Act, TVO and For-tum are liable for all activities associat-ed with management of the nuclearwaste they produce, for the appropriatepreparation of these activities and forall related costs incurred.

In accordance with the Nuclear En-ergy Act, the Ministry of Trade and In-dustry (KTM) makes decisions on theprinciples that must be applied to nu-clear waste management. KTM formu-lated these principles in its decisions of

19 March 1991, 26 September 1995 and23 October 2003. The decisions providea basis for both the practical implemen-tation of nuclear waste management andthe research and development related tofuture measures.

Each company is separately respon-sible for all measures necessary for thetreatment and final disposal of low- andintermediate-level operating waste, andfor the decommissioning of the powerplants. Posiva Oy, a company jointlyowned by TVO and Fortum, is in chargeof the research and development of thefinal disposal of spent nuclear fuel and,ultimately, of the construction and op-eration of the final repository itself.

Posiva is also in charge of compil-ing the plan for and report on nuclearwaste management of the Olkiluoto andLoviisa nuclear power plants, both ofwhich are to be prepared annually. Asprescribed by the Nuclear Energy Actand Decree, this Annual Review 2003describes the status and operations ofnuclear waste management in 2003. Thereport also reviews communication ac-tivities pertaining to nuclear waste man-agement and the provisions made forfuture nuclear waste management costs.

At its Olkiluoto Power Plant in Eurajoki, Teollisuuden Voima Oy operates two boiling water reactors with a nominal outputof 840 MWe (net) each. Olkiluoto 1 (OL1) was connected to the Finnish grid in September 1978, and Olkiluoto 2 (OL2) inFebruary 1980. In 2003, the load factors of OL1 and OL2 were 97.0% and 95.5%, respectively. The operating licences forplant units OL1 and OL2, the storage facility for low-level waste (MAJ Store), the storage facility for intermediate-levelwaste (KAJ Store) and the interim store for spent fuel (KPA Store) will be valid until the end of 2018. The operating licence forthe repository for operating waste (VLJ Repository) will be valid until the end of 2051.

Fortum Power and Heat Oy’s Loviisa Power Plant has two pressurised water reactors with a nominal output of 488 MWe(net) each. Commercial operation of Loviisa 1 (Lo1) began in May 1977, and that of Loviisa 2 (Lo2) in January 1981. In2003, the load factors of Lo1 and Lo2 were 92.4% and 87.9%, respectively. The operating licences for plant units Lo1 andLo2, and the related nuclear fuel and nuclear waste management facilities will be valid until the end of 2007. With respect tothe repository for operating waste (VLJ Repository), the operating licence will be valid until the end of 2055.

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SPENT FUEL MANAGEMENT

PRINCIPLES ANDSCHEDULE

In compliance with the Nuclear EnergyAct and the KTM decisions, prepara-tions are underway for the final dispos-al in Finland’s bedrock of all spent fuelfrom the Olkiluoto power plant and thespent fuel stored to date at the Lo-viisapower plant, as well as that which willaccumulate hereafter. In its decision of23 October 2003, KTM revised theschedule for preparations for the finaldisposal of spent fuel in such a way thatthe preliminary studies and plans re-quired for a construction licence of thefinal disposal facility must be submit-ted in 2009. Provision must be made tosubmit the final studies and plans by theend of 2012 instead of the previousdeadline of 2010. The schedule targetset for the beginning of final disposalwas kept unchanged, in 2020. In themeantime, spent fuel is stored tempo-rarily at the power plant sites.

In December 2000, the Council ofState took a Decision in Principle con-cerning the final disposal of spent nu-clear fuel at Olkiluoto in Eurajoki. Par-liament ratified the decision nearly unan-imously in May 2001. The final dispos-

al facility, consisting of an encapsulationplant and a repository, will be built inthe 2010s. In accordance with the Deci-sion in Principle, an application for aconstruction licence must be submittedin 2016 at the latest.

In 2002, a Decision in Principle wastaken to construct a new nuclear powerplant unit in Finland. At the same time,a Decision in Principle was taken on theextended construction of a final dispos-al facility for spent nuclear fuel in sucha way that the spent fuel from the newplant unit can also be disposed of in thefacility. The waste management obliga-tion of the new plant unit will not beginuntil the commissioning of the plant to-wards the end of the decade.

CURRENT STATUS OFSTORAGE

Spent fuel from the Olkiluoto plant isstored temporarily at the plant units andin the interim store for spent fuel (KPAStore). The installation of new fuel racksin the pools of the KPA Store was com-pleted during 2003. Owing to renovationof the racks, the storage capacity increased

from 4 536 to 7 146 positions. The KPAStore has sufficient capacity for the spentfuel accumulated during about 30 years’operation of the plant units. The store canbe enlarged if necessary.

The twenty-fourth refuelling ofOlkiluoto 1 and the twenty-second re-fuelling of Olkiluoto 2 were carried outduring the year under review. At the endof 2003, a total of 5 786 assemblies ofspent fuel, equivalent to 983 tonnes offresh uranium were stored at the Olki-luoto plant. The KPA Store housed 4 428assemblies; the pools of OL1 stored 746assemblies and those of OL2 stored 612assemblies.

Return transports of spent fuel fromthe Loviisa plant to Russia terminatedat the end of 1996 owing to an amend-ment to the Nuclear Energy Act. Subse-quently, the storage capacity at the Lov-iisa plant was increased in such a waythat, using racks of the current type, thecapacity will be sufficient until 2010. Inthe future, it will be possible to substan-tially increase the capacity through theuse of dense racks.

At the end of 2003, a total of 2 755spent fuel assemblies, equivalent toabout 330 tonnes of fresh uranium (es-timated on the basis of the amount ofuranium contained in the spent fuel,

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FINAL DISPOSALPROJECT

Bedrock investigations atOlkiluoto

Studies into the access area toONKALO

Five new deep investigation bore-holes (KR24–KR28) were drilled in theaccess area to ONKALO. The boreholeshelped establish the structures of thebedrock in the area of ONKALO andtheir significance to the layout of theaccess tunnel to ONKALO.

Furthermore, four shallow bore-holes (PP36–PP39) were drilled and sixgroundwater observation tubes(PVP11–PVP16) were installed in theinvestigation area.

Borehole KR24 was drilled to thecentre of the planned ventilation raise.As the aim was to keep the borehole in-side the raise profile (diameter 6 m), itwas necessary to employ steered drill-ing. Stress measurements were also car-ried out in the investigation boreholewith the overcoring method using Swed-power AB’s modernised Borre probe. Itwas possible to carry out the measure-ments only at two measurement levels,instead of the planned three to four lev-els, owing to equipment problems andthe presence of drill cuttings and piecesof rock in the borehole, despite flush-ing. Furthermore, indications of damagewere detected in the overcored coresamples, for which reason a decisionwas finally taken to terminate the mea-surements. Sixteen measurements in allwere attempted between depths of288 m and 390 m, but only three mea-surements results can be considered rel-atively successful.

Investigation trench TJ7 was dugabove the access tunnel along the tun-nel line. The investigation trench helpedverify the surface rock properties of thefirst part of the access tunnel and, inparticular, the properties of structureRH24. Soil logging was also performedin the trench. Before digging the trench,short drillholes were made along theaccess tunnel line at intervals of about

about 314 tonnes), were stored in theLoviisa plant’s storage facilities. Lo1housed 240 assemblies and Lo2 housed221. The spent fuel storage facilities 1and 2 held 450 and 1 844 assemblies,respectively.

Preparation for the final disposal ofspent fuel continued in accordance withthe Decision in Principle. The sched-ule for the project was defined by thedecision of the Ministry of Trade andIndustry taken in October 2003 in sucha way that the studies and plans requiredfor a construction licence of the finaldisposal facility must be submitted bythe end of 2012 and the preliminary ver-sions of them must be submitted as ear-ly as 2009. On the whole, however, theproject continues to progress in accor-dance with the programme for the pre-construction phase of the final disposalfacility published in 2000 (report PO-SIVA 2000-14).

In accordance with the programme,operations during the year were charac-terised by preparations for the beginningof the construction of the undergroundrock characterisation facility, known asONKALO, in the middle of 2004. Thedesign progressed to the phase of thepreparation of implementation designsand the requests for tenders. The maindrawing stage plan was also reported toSTUK Radiation and Nuclear SafetyAuthority. At the same time, four otherreports linked with the implementationof ONKALO were submitted to STUKfor consideration. They deal with thefollowing subjects:

– description of the baseline atOlkiluoto

– programme for the under-ground investigations

– the monitoring plan– assessment of the disturbances

caused by ONKALO in theimmediate vicinity of therepository.

The first three-year programme“TKS-2003” pertaining to research, de-velopment and technical design was alsocompleted towards the end of the year.In addition to the operating programmefor the next few years, the report in-cludes a fairly comprehensive survey of

the results of the work done during thepast three to four years. The purpose ofthe three-year programme is to promotethe medium-term planning of operationsand, on the other hand, to increase trans-parency of the planning from the view-point of outside evaluation.

10 m to verify the status (thickness ofthe soil cover) and quality of the rocksurface. Towards the end of the year, thefirst pilot borehole was drilled to theprofile of the access tunnel to ONKA-LO. The borehole was completed in ear-ly 2004.

Acquisition of information on thebedrock structure and baseline, andpreparation for the monitoring

About a 600-m-long investigationtrench, TK4, was dug in the central in-vestigation area to establish the defor-mation phases and structures of the Olki-luoto bedrock. Furthermore, short inves-tigation trenches were dug parallel to thetwo new deep boreholes in the vicinityof the point of access to ONKALO. Theinvestigation trench and the boreholetogether help provide information onhow to interpret local structures of thesurface rock. Geological mapping alongthe profile in the north-south directionin the central investigation area provid-ed insight into large structures of thebedrock.

With regard to geophysical investi-gations, emphasis was increasinglyplaced on interpretations of the old andnew measurement results and on geo-logical modelling. Interpretations of theresults of the electrical soundings andthe electromagnetic Gefinex 400S mea-surements performed in autumn 2002provided additional information on, forinstance, the continuity of structuresR20A, R20B and R21. The remodellingof the old results of vertical seismic pro-filing (VSP) confirmed the existence ofsome structural features (nearly verticalstructures) detected from the data pro-vided by magnetic measurements on theground surface.

In the near-field of ONKALO, miseà la masse measurements helped moni-tor the continuity of electrically conduc-tive zones (and structures) between thedifferent boreholes and from the bore-holes onto the ground surface. Further-more, walk-away vertical seismic pro-filing and seismic crosshole soundingswere performed in the surroundings ofONKALO to sharpen the picture of thegeological structure.

The borehole TV imaging was com-plemented in such a way that at the endof 2003 the latest borehole imaged byborehole TV is KR24. Normal geophys-

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ical borehole measurements were car-ried out in boreholes KR23–KR28.

Differential flow measurements andhydraulic conductivity measurementshelped verify and complement data onthe hydraulic conductivity of the bed-rock. The basic principle has been tomeasure new boreholes systematicallywith the aid of a flow meter either bydetailed flow logging, which has givena preliminary view of the hydraulic con-ductivity in the different parts of theborehole, or by complete differentialflow measurement, which has enabledcomprehensive analysis of the hydrau-lic conductivity and flow conditions inthe borehole. In addition to these, thepurpose of differential flow measure-ments was to explore poorly hydrauli-cally conductive areas deep in the bed-rock. The measurements were aimed atdetecting highly saline zones or fracturessuitable for water sampling. Further-more, the flow meter was employed tospecify and complement the values ofhydraulic head, particularly in suchborehole sections from which the pre-vious results had been defective or un-certain owing to fracturing or other tech-nical reasons. Hydraulic conductivitymeasurements with the hydraulic test-ing unit (HTU) mainly focused on char-acterising the poorly hydraulically con-ductive rock at the final disposal depthand in its vicinity (300–700 m).

Monitoring measurements contin-ued. Measurements that have beenlaunched previously include, for in-stance, measurement of the pressurehead, measurement of the thickness ofsnow and frost, monitoring of the tem-perature and precipitation, and hydro-geochemical measurements. New mon-itoring measurements that complementthe baseline include, for instance, mea-surement of the amount of dust and theamount of water infiltrating into the soil.Water permeability of the soil was alsostudied by means of test pits, from whichsoil samples were taken. The sampleswere analysed to determine the waterpermeability, chemistry, organic impu-rity, water content, and grain size distri-bution.

With regard to surface hydrology,long-term monitoring measurements ofthe groundwater level continued withinthe same scope as previously. System-atic measurements of the surface runoffbegan in the spring at four measuringweirs.

The measuring system of smallmovements of the bedrock, known as theGPS network, consists of a permanentstation and nine local stations. The net-work was extended by two stations lo-cated north of the strait of Olkiluo-don-salmi. Station GPS10 on the island ofOlkiluoto is located at the constructionsite of the new nuclear power plant unitand must therefore be closed. Conse-quently, a new station was built at Ot-pää, which will replace the old one inthe measurements to be conducted in2004. Measurements in autumn 2003were made at both stations.

The extension of the microseismicstation network was also launched. Thepresent network of six stations was de-signed on the basis of the previous lo-cation plan for the ONKALO facility.

Interpretation of the hydrogeologi-cal data was performed, for instance, byanalysing properties of individual hy-draulically conductive fractures, com-bining data from the results of detailedflow logging of flow measurements,optical borehole TV imaging and coresamples. The distribution of the salinityof groundwater was analysed on thebasis of water samples and flow mea-surement results. The results of the in-terference test carried out in 2002 be-tween boreholes KR14–KR18 were in-terpreted by both analytical methods anddigital flow models.

The main objective of the flow mod-elling was to assess the effect of ONKA-LO on the groundwater level and on thedistribution of saline groundwater. Inthese assessments, the principal tool wasthe computer software called FEFTRA,which has been especially developed todeal with problems with the free surfaceboundary condition. The main conclu-sions relating to the effects of ONKA-LO were based on a few calculated cas-es, one of which assumed that theamount of water seeping into ONKA-LO would not be reduced by any tech-nical measures. The calculated casesalso included an extreme case corre-sponding to very successful grouting.The results show that without any grout-ing at all, the amount of water seepinginto ONKALO stabilises at a level ofabout 100 l/min, in which case the max-imum reduction in the groundwater ta-ble would be about 300 m. In the casecorresponding to very successful grout-ing, the amount of water seeping intoONKALO would be about 20 l/min, the

reduction in the groundwater table thusbeing about 30 m. On the basis of theresults, saline groundwater (having aconcentration of 40–55 g/l, dependingon the case) would seep into ONKA-LO.

Hydrogeochemical investigations

The hydrogeochemical description ofOlkiluoto was updated by the hydro-geochemical result material gathered in1999–2002. Deeper insight was gainedparticularly into groundwaters in the soillayer and the upper part of the bedrockand into the salinity distribution and dis-solved gases of deep groundwaters. Thedescription represents the current base-line at Olkiluoto before the constructionof ONKALO begins. During 2003, thedistribution of the groundwater typesoccurring at Olkiluoto was described forthe first time with the aid of a 3D modelas well.

Hydrogeochemical investigationsfurther concentrated on studies into theregional distribution of the salinity, thedefinition of dissolved gases and thebaseline in the investigation areas, sincethe aim is to update the description ofthe hydrogeochemical baseline oncemore using the result material on whatis called the undisturbed status gatheredbefore beginning the construction ofONKALO. A total of 27 groundwatersamples were taken from deep bore-holes. Of these, ten water-samplingpoints were chosen in such a way thattheir results primarily contribute to de-tailed planning of the monitoring pro-gramme for ONKALO to be launchedin 2004. In selecting the samplingpoints, however, attention was alsodrawn to the fact that the results wouldbe available for verification and finish-ing of the description of the hydro-geochemical baseline at Olkiluoto. Atotal of 14 gas samples were taken. Theresults will be reported for the first timein English in the first part of 2004.

Water samples were taken from theshallow boreholes drilled in the bedrockand from the standpipes installed in theground in early summer and in autumn.In summer, samples were taken from 14sampling points in all. The sampling inautumn mainly concentrated on watersampling from the shallow boreholesdrilled in the bedrock and from thestandpipes, both in late autumn. In ad-dition, the purpose of the water sampling

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was to examine the seasonal variationsand, with respect to the new samplingpoints, to acquire water samples of theundisturbed status before the construc-tion of ONKALO begins. The resultswill also be reported in English in thefirst part of 2004.

The condition of the multi-packerequipment installed in borehole KR1 atHästholmen in 2000 was checked inautumn 2003, and the pH and electricalconductivity values of the groundwaterin the sampling sections were measuredat the same time. The need for watersampling will be assessed on the basisof the results in 2004.

Environmental studies

The first summary of the environmen-tal studies at Olkiluoto that covered thedifferent fields was drawn up and includ-ed in the report on the baseline. Futureenvironmental studies were defined forthe monitoring programme. To help in-terpret the changes, a study was com-missioned on the predictions of climatechange for the Olkiluoto area.

The basic survey of the forest eco-systems launched in 2002, which willlast for several years, continued with aforest inventory by vegetation type com-partments. The results obtained will helpassess, for instance, the species, age andsize distribution of the tree stand with aview to monitoring any changes andproviding basic data for the modellingof the biosphere. A regular network ofobservation points was marked in thefield for forest studies to be conductedthe following year.

Continuous long-term monitoringof precipitation was begun by establish-ing eight observation areas, in which theamount and composition of rainfall ismonitored inside a forest stand and inclearings. The purpose of the monitor-ing of precipitation is to examine theeffects of treetops on rainfall and, in alater phase, to monitor the spreading ofdust caused by surface development andcrushing work. A lysimeter network wasalso established in one of these inten-sive observation areas to help acquireinformation on the amount and qualityof water moving in the surface layers ofthe soil. In addition, regular snow andfrost observations continued as before,and two new frost observation pointswere established as part of the lysime-ters.

The monitoring data for the pastyear on the weather conditions, the ma-rine ecosystems and the radioactivity ofthe environment gathered by Teollis-uuden Voima Oy were also stored in Po-siva’s archive for use and later report-ing in accordance with the monitoringprogramme. Furthermore, water sam-pling from the groundwater pipes andshallow boreholes continued.

Equipment and methoddevelopment

The absolute pressure transducers in-stalled in the differential flow measure-ment units were tested and put into use.The transducers were found to be direc-tion-dependent, and consequently mag-netometers were also installed in theborehole probes, thus enabling the de-viation caused by the direction-depen-dence to be taken into account in theresults. New electronics cards weremade for all the differential flow mea-surement units. The computer used forthe older differential flow measurementunit was replaced to better meet theneeds of the sophisticated measuringsoftware. The flow guides in the old dif-ferential flow measurement unit werereplaced as well. The measuring equip-ment will possibly also be used as partof the excavation of ONKALO for hy-draulic conductivity measurements inthe probe boreholes to be drilled in thetunnel drift after every third round. Astudy was therefore launched with aview to building a new, slightly lighterversion of the equipment for use in theONKALO facility.

The new transverse flow measure-ment equipment was completed at theend of 2003, but its testing was post-poned to 2004. The electronics of themeasuring equipment is now similar tothat of the differential flow measurementunit. In addition, a magnetometer wasinstalled in the equipment, which en-ables the direction of the equipment inthe borehole to be determined accurate-ly. The equipment also includes the Sin-gle Point Resistance measurement prop-erty. The structure of the flow guide ofthe transverse flow meter was renewed,and as a result it was possible to remove

the solenoid valves that are damagedeasily. The flow guide now has two sec-tors instead of the four sectors before.In building the new transverse flowmeasurement equipment, its possibleuse for measurements in the tunnels wasalso taken into account (e.g. the highhydrostatic pressure).

The Single Point Resistance mea-surement property was added to the hy-draulic testing unit (HTU), thus facili-tating the depth calibration of measure-ments. The function is similar to that ofthe differential flow measurement units,and consequently the results obtainedwith the units are better comparable withrespect to the measurement depth. Testsshowed that the unit functioned as ex-pected.

Development work on the equip-ment known as TERO intended to mea-sure the thermal properties of the bed-rock in situ continued by constructing aprototype transducer. The equipmentwas tested in the test borehole of theGeological Survey of Finland (GTK)and its technical performance was foundgood. Some minor teething problemsmust be resolved before field tests, how-ever. The beginning of preparation ofthe interpretation software for the mea-surements was delayed and will beginin 2004.

The development work on rockstress measurement based on the over-coring method, carried out jointly withSKB, could be utilised in the qualityassurance of the measurements in KR24.The development work continued byanisotropic examination of the Olkilu-oto bedrock: Laboratory analyses (mod-ulus of elasticity and compressivestrength) show that the degree of anisot-ropy of mica gneiss is 1.4.

Renovation of the sampling equip-ment for deep groundwaters, known asthe PAVE equipment, was completed,and as a result there are now four setsof equipment in all. Three sets of equip-ment were operated, for which reason anew, third motorised hose winch wasalso manufactured. This makes instal-lation of the equipment in the boreholeeasier and faster. Two new large pres-sure vessels with a volume of 500 mlwere manufactured for the PAVE equip-ment, but their testing was postponed to2004.

Three slim membrane pumps to beinstalled in the measuring hoses of themulti-packer equipment were manufac-

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tured during the year. The structure ofthe pumps was simplified at the sametime, and as a result the manufacture alsobecame slightly easier. The pumps wereput into use in summer and they havefunctioned well.

Mass spectrometry equipment wasacquired to determine the gases dis-solved in the groundwater. The equip-ment enables gases to be analysed fromboth the aqueous phase and the gasphase using different sampling methods.During autumn, development of theanalysis method mainly focused on theanalysis of gases from the gas phase. Theresults of the first phase of method de-velopment were reported in February2004.

Studies of the investigation equip-ment and measuring methods suitablefor use in ONKALO were launched, anddevelopment work on some methodsbegan. These include, for instance, bore-hole video imaging, measuring seepagewater weirs, and instrumentation of thegroundwater stations. Studies were alsolaunched to investigate the effects ofchanging the material used for the pack-er equipment connecting rods from steelto carbon fibre.

ASSESSMENT OFLONG-TERM SAFETY

Studies on the performance ofengineered barriers

The objective of performance analysesis to study the functioning of engineeredbarriers and to adapt the details of thefinal disposal concept to the conditionsat Olkiluoto. This background materialand basic data will be used both for theinterim report on the safety analyses tobe submitted to STUK in 2006, and fordesign and requirements management ofthe final disposal system. The studies areconducted to a great extent under inter-national co-operation programmes at theÄspö and Grimsel Hard Rock Labora-tories and under EU projects. The phe-nomena affecting the performance thatparticularly depend on the conditions atOlkiluoto will be later investigated inONKALO.

The joint project launched by SKBand Posiva concerning the corrosion of

copper in a saline groundwater environ-ment continued, including both experi-mental research and theoretical studies.Corrosion investigations were carriedout in Canada, Sweden and Finland. Thepurpose has been to create test condi-tions that correspond as closely as pos-sible to the final disposal conditions.The capacity of bentonite to resist andretard the transmission of unfavourablecorrosive conditions from the bedrockonto the canister surface is of great im-portance in the potential corrosion pro-cess. Investigations into the redox con-ditions prevailing in bentonite and thecomponents affecting the redox condi-tions of bentonite and their measurementtherefore continued.

Prototype repository

The KBS-3 final disposal concept is be-ing tested and demonstrated under theEU’s “Prototype Repository” project byconstructing a full-scale long-term testfor a sealed final disposal tunnel. Posi-va and VTT are involved in developingthe conceptual and mathematical mod-elling of engineered barriers. The workdone in 2003 concerned modellingchanges in the pore water of the bufferand backfilling material.

Swelling pressure

It is characteristic of bentonite that insaline water its swelling pressure andexpansion capacity are reduced. To en-sure a sufficient swelling pressure, thebentonite must be initially compacted toa sufficient density. In 2000–2003, Po-siva and SKB jointly conducted experi-mental studies into the swelling pressureas a function of the bentonite density andthe ionic strength and ionic form of thesolution, and interpreted the results onthe basis of theoretical models. Posiva’scontribution consisted of studies into theimportance of pore-water chemistry asa determining variable for swelling pres-sure. The need to continue the develop-ment of modelling and the experimentalresearch will be assessed on the basis ofthe summary report, which is being com-pleted.

Release mechanisms of uranium

The EU’s project named “Rates andmechanisms of radioactive release and

retention inside a waste disposal canis-ter (IN CAN PROCESSES)” investi-gates canister-internal processes duringthe potential release of radionuclidesfrom spent fuel. The degradation rate offuel has been studied both under oxidis-ing conditions and under reducing con-ditions buffered by iron. In Finland, theeffect of alpha radiolysis was studiedwith the aid of 233U-doped UO2, whichsimulated the alpha activity of spent fuel3 000 and 10 000 years after the finaldisposal. Some indications of an increasein the dissolution caused by alpha radi-olysis were detected in short-term testsin bicarbonate waters under reducingconditions. Chemical and electrochemi-cal measurements show that the reduc-tion of uranyl-carbonate complexes alsooccurs in a solution that contains corro-sive iron; in other words, the reductionneed not necessarily occur through sorp-tion on the surface of iron/iron oxide.(Several SKB-TR reports have beenpublished on this work, and correspond-ing reports in the Posiva series of re-ports are being completed).

In 2003, Posiva and SKB jointlystudied the release mechanisms of ura-nium from, for instance, gadolinium-doped uranium dioxide, which had beenoxidised to the predetermined oxidationstate UO2,3 under controlled conditions.This helped simulate the oxidation ofuranium (UO2) contained in spent fuelto the cubical U4O9+x state. The detect-ed increase in the lattice parameter ofcubical oxide during the dissolution re-action in oxygen-free bicarbonate wa-ter suggests the selective dissolution ofuranium with valence 6 from the solidphase. A report on this work was pub-lished in the Posiva series of reports.

FEBEX

Posiva is taking part in the FEBEX IIproject by examining, from the samplesof the in-situ test, the chemical effectscaused by concrete on bentonite near theinterface of these materials. The samplesof the in-situ test were taken in the springof 2002 and the results were reported inspring 2003. After five test years, the ef-fects of concrete could be detected inbentonite at a distance of over 10 cmfrom the interface.

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CROP

Posiva is involved in the EU’s projectnamed “Cluster Repository Project – ABasis for Evaluating and DevelopingConcepts of Final Repositories for High-level Radioactive Waste (CROP)”. Be-sides the EU countries, others involvedare Japan, Canada and the USA. Towardsthe end of the project, data and experi-ence were gathered from the perfor-mance analyses of engineered barriers.The working meeting of the CROPproject was held at Olkiluoto in autumn2003.

LASGIT

In 2003, SKB and Posiva jointlylaunched the LASGIT project. Thisproject aims at studying the migrationof gas through compacted bentonite bymeans of a large-scale test. The resultsobtained from the test will increase un-derstanding of the gas migration processand enable the testing of migration mod-els on a large scale. Installation work ofthe test is being completed in the firstpart of 2004.

LOT

Posiva is involved in the LOT test(Long-Term Test of Buffer Material) tobe carried out at the Äspö Hard RockLaboratory. The test pertains to validat-ing the hypotheses and models of long-term processes occurring in the buffermaterial, and the closely linked process-es concerning microbiology, the migra-tion of radionuclides, copper corrosionand the migration of gas. The tests areperformed at a depth of about 500 m, inboreholes drilled in the tunnel bottom;the boreholes have a diameter of 30 cmand a depth of 4 m. The tests to be per-formed in five boreholes were begun in1999, and they have been planned to lastfor 1, 5 and 20 years. The results of thechemical studies were reported in 2003(Posiva’s working report 2003-32); theywere obtained by analysing the samplesof the first test borehole. Pore waterswere pressed from the bentonite sam-ples; pH, Eh, S(-II), Fe2+, Na+, K+, Ca2+,Mg2+, Cl-, SO4

2- and HCO3- were deter-

mined from the pore waters. The ex-changeable cations and water content ofbentonite were determined as well. Theexchangeable calcium content of ben-tonite had increased in comparison with

the original MX-80 bentonite. This wasconsistent with the low calcium contentsdetected in the pore water. The effectsof additions on the exchangeable cationsmostly remained within the scope ofnormal variation.

BENIPA

The EU project named “Bentonite bar-riers in integrated performance assess-ment (BENIPA)”, included in the fifthframework programme, was completedin 2003. VTT Processes, supported byPosiva, was responsible for compilingthe databases that deal with the features,events and processes (the FEPs) and forgathering the data on crystalline rock.A working report was drawn up on theuse of the commercially available PCmodel named PORFLOW for the migra-tion analyses of radionuclides in theKBS-3V and KBS-3H final disposalholes and on its comparison with theREPCOM model. The European Com-mission will publish a final report on theBENIPA project.

ECOCLAY

In 2000–2003, Posiva was involved inthe EU project named “ECOCLAY II(Effects of Cement on Clay Barrier Per-formance Phase II)”, which investigat-ed interaction between bentonite andcement in the environments of both clayand crystalline bedrock. The Finnishcontribution consisted of studying par-ticularly the effect of the salinity andhigh pH of groundwater in the systemformed by compacted bentonite andcrushed rock. The alteration of bento-nite and crushed rock and the sorptionand migration of the tracers (Na, Ca)were monitored as a function of the ionicstrength and pH. The final report ofECOCLAY II will be completed in thefirst part of 2004.

The NEA’s EBS project

The NEA’s “Engineering barrier sys-tems” project consists of a series ofworkshop meetings, which have beenplanned to be held annually. The firstmeeting was arranged in Oxford in2002. It was preceded by an inquiry thatexamined requirements for the perfor-mance of engineered barriers and theirhandling in safety analyses. The topicsfor future meetings were agreed on in

the first meeting.Posiva hosted the second meeting

in the series. The topic was the require-ments for the design and performanceof engineered barriers. The meeting washeld in Turku from 27 to 29 August2003. The meeting concluded that thedesign, construction and operation of afinal disposal system form a complicat-ed project, in which the requirements setby several parties must be taken intoaccount. Tools are available for manag-ing the requirements, which can be ap-plied to the final disposal project to helpsystematise the work and to verify thatthe requirements set for the design willbe fulfilled in a satisfactory manner.Management of the requirements andsystematisation of the safety analysiscomplement each other. They partly uti-lise the same basic data and methods(e.g. official requirements, site-specificinformation, iterative working methods,change management), and they havesimilar needs (traceability, quality assur-ance, interaction). Active interactionwas found to be an important factor inconsidering the waste management op-tions and in developing design concepts.

NF-PRO

During 2003, Posiva was involved in thepreparation of and application for theIP project entitled “Understanding andphysical and numerical modelling of thekey processes in the near-field, and theircoupling, for different host rocks andrepository strategies” (NF-PRO). Be-sides Posiva, the project involves VTTProcesses and 44 other organisations.The project is included in the EU’s sixthframework programme and consists ofsix subprojects, of which VTT and Po-siva actively participate in four. Thespecial subjects of their own include thedissolution of UO2 doped by alpha ac-tivity, the evolution of pore water chem-istry of bentonite (particularly pH, Ehand salinity), the corrosion products ofiron and copper in bentonite, the THMbehaviour of bentonite in the KBS-3Vconcept, and the integrated examinationof all the sub-phenomena from the view-point of safety analysis. The project waslaunched in the beginning of 2004 andwill continue until the end of 2007.

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Functioning of the bedrock asa barrier

In 2003, the EU project named “RET-ROCK”, which studies the modellingmethods and concepts of migration andretention in the bedrock, arranged an in-ternational expert seminar to assess pre-vious achievements of the project andto outline future work. The EuropeanCommission will publish a summary ofthe workshop.

Studies into the migration phenom-ena continued jointly with other wastemanagement organisations at the ÄspöHard Rock Laboratory. The TRUEBlock Scale tests continued in the fol-low-up project, in which the measure-ment of the tracers with the strongestsorption continued to determine the tailsof the penetration curves. At the sametime, additional modelling work wasdone with a view to interpreting the pre-vious and new results. The work doneunder the joint modelling project withinthe Task Force focused on additionalstudies linked with the heterogeneity ofthe migration path. The effects of he-ter-ogeneity with respect to the safety anal-ysis were considered by extrapolating thetest results for a situation correspondingto the final disposal conditions. Theseco-operation projects are discussed be-low in the section entitled “The ÄspöHard Rock Laboratory”.

Sorption tests continued with a viewto increasing the theoretical understand-ing of sorption and developing themechanistic modelling. The tests withdifferent concentrations of caesium haveshown non-linear effects on the reten-tion of the tracer caesium. The exposureof a sample to caesium before the re-tention test may have reduced the reten-tion significantly, but in some cases aconsiderable alteration occurred in therock, which resulted in intensified re-tention.

Examination of the migration in afracture by means of tests carried out ina natural fracture brought to a laborato-

ry continued by studying, for instance,the hydraulic conductivity of the frac-ture and the location of flow paths. Pre-liminary migration tests of radionuclid-es were carried out using tracers withnegligible sorption (99mTc, sodium fluo-resceine) and sodium with low sorption.

Research aimed at defining thesorption mechanisms of europium andamericium continued by studying theirretention in kaolinite. In 2003, Posivacontinued to be involved in the work ofthe NEA’s “Sorption Forum II” projectand the third phase of the TDB (Ther-modynamic Data Base) project.

Investigation of the compatible andconsistent migration modelling methodsbegan under the migration project(named KULKE), formed jointly withsorption and migration modelling engi-neers and experimental migration re-searchers. The project covered experi-mental studies and modelling methodsof both the near-field and the far-field.In the future, some of the investigationsunder the KULKE project will receivefinancing from the State Nuclear WasteManagement Fund, forming part of theFinnish nuclear waste research pro-gramme (KYT). Some of the investiga-tions have been proposed to form partof the FUNMIG project, which is in-cluded in the EU’s sixth framework pro-gramme, now in its preparation phase.The project could begin from the begin-ning of 2005 at the earliest. Beforelaunching the FUNMIG project, Posi-va continues to provide financing for theinvestigations.

Potential changes in the prevailingflow conditions and hydrogeochemicalconditions at the Olkiluoto investigationsite caused by waters seeping into theONKALO facility were studied by mod-elling both the entire area and the as-sumed flow path in detail. The studiesform part of the assessment report onthe disturbance caused by ONKALO,and detailed reporting on both studiesis being completed in the first part of2004.Biosphere studies

Guidelines for the biosphere studieswere defined in the three-year researchprogramme (TKS-2003) and in the mon-itoring programme. A summary that cov-ered all the different sectors of biospherestudies, vital for the assessment of long-term safety as well, was drawn up as apart of the report on the baseline.

The modelling project on the eco-systems that are located on dry land andreceive potentially contaminatedgroundwater progressed particularly atthe expert seminar arranged by SKB inMay 2003.

The first version of the versatile andflexible biosphere-modelling tool(BIOMAT) tailored for the Matlab/Simulink calculation environment wascommissioned jointly with SKB, and thedevelopment work is being continued in2004.

The second year of operation of theBIOPROTA project, partly financed byPosiva, began in the autumn of 2003.The joint project of the nuclear wastemanagement organisations concentrateson establishing the key issues of bio-sphere modelling. A considerableamount of work material on central sub-areas was already produced during thefirst year.

Posiva continued to monitor theprogress of other international projectslinked with biosphere modelling (e.g.BioMoSA, BIOCLIM, FASSET). In ad-dition, Posiva’s representative attendedthe conference organised by the IAEAin Stockholm in October, which consid-ered preconditions for the implementa-tion of radiation protection and oppor-tunities for the practical arrangements.

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Snow collectors erected in an intensive observation area inside a forest stand, which help examine,for instance, the effects of treetops on the chemical composition of falling rain and snow.

Leena Hamberg of the Finnish Forest Research Institute making an inventory of the coverage ofundergrowth species with the aid of a portable frame. Photo: Maija Salemaa

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Safety analysis

Assessment of the disturbances causedby ONKALO was completed, which alsotook account of the hydrological andgeochemical disturbances within thescope of the separate studies per-formed. The assessment report on thedisturbances was submitted to STUKand the members of the internationalassessment group, first as a draft in Au-gust and as a final version in late autumn,for evaluation before construction of theONKALO facility begins. Posiva wasalso involved in drawing up and com-menting on other reports to be submit-ted to STUK from the point of view ofsafety assessment.

As an expert in safety analysis, VTTProcesses was involved in the ground-water control project, which produceda working report on the principles ofgroundwater control and the effects ofseepage waters and, on the other hand,their reduction measures, as well as thefinal report on the entire project.

The experts in safety analysis werealso involved in drawing up a new three-year programme for the research, devel-opment and technical design, and inplanning the material necessary for theinterim report to be drawn up in 2006.

As one of the preparatory phases ofsafety analysis, the Process Report ofSR 97 was localised to correspond toPosiva’s plans and the conditions atOlkiluoto. The Process Report also tookthe Finnish research findings into ac-count as supplementary factors. The re-port was ready for publication in Feb-ruary 2004.

Co-operation and the exchange ofinformation concerning safety analysisin particular consisted of, for instance,participation in the work of the OECD/NEA. Within the OECD/NEA, Posivawas involved in the work of the “Inte-gration Group for Safety Case” (IGSC).During 2003, the IGSC arranged, for ex-ample, the first meeting of the interna-tional AMIGO project “Approaches andMethods for Integrating Geological In-formation in the Safety Case”.

During 2003, Posiva and SKB joint-ly implemented the basic design phaseconcerning the horizontal location of the

canister. This basic concept is called theKBS-3H concept, to distinguish it fromthe concept in which the canister isplaced in the vertical position (KBS-3V). This installation technique wouldinvolve a new type of concept in whichthe canisters and bentonite blockspacked into perforated steel drumswould be installed in about 200-m-longhorizontal disposal holes. The work isbeing done in several phases. The ob-jective of the many-year developmentprogramme is to enhance the KBS-3Hconcept so as to reach the level of theKBS-3V concept in technical terms, andto demonstrate the drilling of disposalholes and the installation of canistersand bentonite blocks in the long hori-zontal holes. The objective of the workconducted in Finland is to draw up theSafety Case of the KBS-3H concept in2007, with Olkiluoto as the model site.

FINAL DISPOSALTECHNOLOGY

General

During 2003, the preliminary planningphase was completed and plans for thefinal disposal facility were collected to-gether in a consistent form as a plant de-scription (Posiva’s working report 2003-64). The plant description is the firstplant design that has taken the infrastruc-ture at Olkiluoto into account. Moreover,the plant design preliminarily took ac-count of the effects of the OL3 plant,whose construction was confirmed in2003, on the final disposal. The designsystem of the plant was developed dur-ing 2003 by introducing the numberingand nomination systematics for the fu-ture systems.

Development of the factors highlysignificant for the final disposal systemwas monitored in the design work. Thesefactors include, for instance, burnup ofthe uranium fuel and the resulting radia-tion and decay heat properties. Theywere updated during the year under re-view and taken into account in develop-ing the final disposal system and design-ing the plant.

Development of the managementsystem of the design requirements con-tinued. The requirements defined for theONKALO facility acted as a model case.The management system was developedunder a joint project co-ordinated by theTechnical Research Centre of Finland(VTT).

The development and design worklinked with encapsulation and the re-pository is described in more detail be-low.

Canister design

The study and comparison of the canis-ter design jointly with SKB continued.On the basis of the studies, details ofthe designs for the copper canister andinsert were slightly changed and themodifications were recorded in a mem-orandum. The canisters intended forBWR fuel are now practically similarin SKB’s and Posiva’s designs.

The canister design for the new nu-clear power plant was drafted on thebasis of the negotiated plant type, but asthe plant type was confirmed towards theend of 2003 as being an EPR plant, thecanister design will be specified during2004. The greatest modifications resultfrom the fact that the fuel assembly islonger than the assemblies of the OL1and OL2 plants, and that the PWR as-sembly is larger in other respects as well.Consequently, a much lower number ofassemblies can be placed in one canis-ter, four pieces at most on the basis ofpreliminary calculations. A report will bedrawn up on the design of the new can-ister and on the updated designs of theprevious canisters.

It has been assessed that the canis-ter will be subjected to a maximum pres-sure of about 45 MPa at the final dis-posal depth; the 3-km-thick ice layer thatcan form during the potential future gla-ciation was considered in the assessment.The mechanical strength of the canisterwas determined experimentally and, fur-thermore, SKB launched a project toprove with the aid of methods based onprobability calculation that the probabil-ity of canister failure is low.

The acceptance criteria for canistermanufacturing technology were consid-

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ered jointly with SKB, but the prepara-tion of a proposal was postponed to2004.

Canister manufacturingtechnology

With regard to canister manufacturingtechnology, one of the principal devel-opment subjects continued to be themanufacture of the cylindrical part of thecopper canister from one piece with sev-eral optional manufacturing methods.Manufacturing methods were developedboth under the TEKES product devel-opment project of Posiva and Outokum-pu Poricopper, and as a co-operationproject with SKB. The TEKES productdevelopment project was originallyplanned to be completed at the end of2003, but owing to some delays theproject will continue until the end of June2004.

Development work on the coppercanister material continued jointly withOutokumpu Poricopper. The billet cast-ing process was upgraded with a viewto achieving a longer billet that meetsthe specifications. In the casting process,the feeding of melt into the mould wasmodified, thereby reducing the oxygencontent to a sufficiently low level evenin the beginning of the casting. The mi-cro-alloying of phosphor was improvedin such a manner that the phosphor con-tent is in accordance with the specifica-tions along the entire casting length.Solidification of the cast is now con-trolled better in the beginning of thecasting, and as a result the centre crackof the base of the billet is reduced andthe wastage of material is thus smaller.Owing to the better control of the cast-ing process, the billet surface quality hasalso improved, which means there is lessneed to machine the surface of the bil-let. Sampling from the billet was modi-fied, which further contributed to asmaller wastage of material. After mod-ifications of Outokumpu Poricopper’scasting equipment and process, Posivaand SKB jointly ordered eight billets forthe three different canister manufactur-ing processes, the “pierce and draw”method, the extrusion method and theforging process. The billets met thespecifications for composition and

weight, but no specifications exist yetfor permissible cracks or other flaws andthe surface quality.

Manufacturing tests of the seamlesscopper canister fitted with an integrat-ed bottom continued with the “pierceand draw” method at the pipe factory ofVallourec & Mannesmann Tubes inGermany. One canister was manufac-tured with this method and the first hot-forming phases of the second canisterwere performed during 2003. The re-search team formed by Vallourec &Mannesmann had planned modifica-tions to the hot-forming process in or-der to make the grain structure of thebottom finer. The hot-forming processof the first canister was modified afterthe previous test carried out in 2002 insuch a way that at the end of the hot-forming the canister bottom was hot-formed against a blind flange. Destruc-tive inspection of the bottom showed,however, that the grain structure in thecentre of the bottom continues to berougher than elsewhere, which provedthat the hot-forming grade of the bot-tom had remained too low. The researchteam carried on the development workby planning modifications to the lastphases of the hot-forming process witha view to raising the hot-forming gradeof the bottom. The canister was hot-formed after these modifications, andthe canister investigations are beingcompleted in the first part of 2004, whenthe hot-forming of the second canistercan be continued. The manufacturingtests have been planned and carried outjointly with SKB.

Forging tests of the copper canisterand copper lids continued under a jointproject of Posiva and SKB at the facto-ry of Scana Steel Components AB inSweden. The forging of the pipe forgedin 2002, which remained slightly short,was continued using new forging toolsthat better corresponded to the form ofthe pipe. The pipe now reached fulllength, but cracks were detected at itsends. In 2003, one new pipe was forgedusing the same new tools. The measure-ments and grain structure of this pipefulfilled the requirements specified forthe canister pipe. However, the innerdiameter of the pipe has grown too largeduring the hot-forming and the form ofthe pipe is not completely even. A new

tool was ordered for the last phase ofthe pipe hot-forming to improve themethod further. Kungliga Tekniska Hög-skolan (KTH) in Stockholm was in-volved in the development work on themanufacturing process of copper lids,whose aim was, for instance, to makethe grain structure of the lid finer and toincrease the yield of the process. Cop-per lids have already been forged in se-rial production, their grain structure nowmeets the specifications throughout andthe wastage of material has decreased.

SKB continued development workon the extrusion method of the coppercanister at Wyman & Gordon in Scot-land. In 2003, three pipes were extrud-ed, one with a wall thickness of 40 mmand two with a wall thickness of 50 mm.All pipes fulfilled the requirements setfor them.

Comparison of the different canis-ter manufacturing methods and prepa-ration of their cost estimates began joint-ly with SKB. The cost comparison willbe completed in the first part of 2004.

A casting test of the canister insertmade of nodular cast iron was carriedout at Metso Paper Oy’s RautpohjaFoundry. The casting test was designedjointly with SKB, which simultaneous-ly had similar casting tests carried outby three foundries in Sweden. Com-pared with Posiva’s previous casting test(in 1998), the stabilisation holes wereomitted from the insert and casting ofthe bottom was integrated. The targetsand quality requirements of the castingtests were consistent. One of the targetsof the tests was to improve the tough-ness and tensile properties of the cast-ing. The results of the manufacturing testfulfilled the requirements in all otherrespects except for the mechanical prop-erties of the material and the cast struc-ture. The tensile strength, breakingstrength and ultimate elongation valuesremained below the requirements. Met-allographic examinations showed thatthis was due to a wrong type of caststructure. The graphite had not beennodulised in accordance with the re-quirements, which apparently resultedfrom a malfunction or a fault in the cast-ing process. A new casting test has beenplanned to be carried out to manufac-ture an insert that fulfils the require-ments in all respects.

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Canister sealing and inspectiontechnology

Posiva continued development of thehigh-vacuum electron beam welding(EBW) method intended for sealing thecopper lid of the canister by re-imple-menting the welding test programme of2002, which failed owing, for instance,to equipment failures and problemslinked with the joint surfaces of the lids.The welding equipment employed in theprevious test programme had been trans-ferred to ISF in Aachen, and conse-quently the new tests were carried outthere. To verify the welding parameters,two series of plate tests were performedfirst, of which the latter succeeded bet-ter, thanks to the modified welding pa-rameters. Two lid weldings were madeafter this. The gaps of the lid and thepipe joint surface had been dimensionednil, and thus the pipe had to be preheat-ed both times to about 70°C to be ableto install the lid in its place. During theweldings, it was necessary to use a work-ing distance different from that of theprevious plate welding tests, but no new‘focus tests’ were carried out, however.Both pipes were subjected to a radio-graphic inspection at SKB’s canister lab-oratory, which showed that the weldswere extremely porous throughout theweld area. The analysis of the test re-sults and the reporting are underway.

In the course of the developmentprogramme of the electron beam weld-ing method it has been detected that theimplementation of test programmesabroad and with constantly changingequipment is rather laborious and slow.Owing to the co-operation agreementconcluded with Patria Aviation Oy, Po-siva has been offered an opportunity toimplement the welding test programmesat Linnavuori, at the electron beamwelding equipment employed by PatriaAviation. During 2004, the equipmentwill be modified for this purpose; forinstance, the welding power will beraised to 50 kW. Posiva will be able toimplement its subsequent test pro-gramme immediately after the equip-ment is ready for use, possibly in theautumn of 2004.

Posiva increased its resources in thesub-areas of the sealing and inspectiontechnology of encapsulation technolo-gy to intensify its co-operation with SKB

and to enable increasingly active in-volvement in SKB’s EBW and FSW(Friction Stir Welding) projects. SKBaims at selecting the sealing method tobe used for encapsulation and at prov-ing its performance in the first part of2005, for which reason SKB’s develop-ment programme of sealing technologyis progressing at a hectic pace. NewFSW equipment, developed by TheWelding Institute (TWI) and suppliedby ESAB, was installed and put into useat SKB’s canister laboratory in Oskar-shamn. Furthermore, the EB weldingequipment of the canister laboratory wasmodified.

Posiva continued to be involved inthe domestic TEKES/EU project imple-mented by Helsinki University of Tech-nology and the Technical Research Cen-tre of Finland (VTT) with a view to in-creasing expertise and resources in thefield of FSW technology. The projectwill continue until the autumn of 2004.

The narrow-gap TIG welding tests,commissioned by Posiva from HelsinkiUniversity of Technology and their re-porting were completed. Using theequipment at Helsinki University ofTechnology, it was possible to weld a 15-mm-thick copper plate with reasonablepreheating, whereas the welding of a 50-mm-thick plate did not succeed at alldespite preheating. In accordance withcalculations, the welding of so thick amaterial using the narrow-gap TIG weld-ing equipment would require the preheat-ing of approximately 500–700ºC, whichwill be practically out of the question inthe encapsulation of spent nuclear fuel.

In the field of inspection technolo-gy, groundwork was laid for develop-ment work on processing the results ofthe inspection methods by ordering as-sessment of Posiva’s and SKB’s devel-opment work on canister inspectiontechnology to date and, on this basis, afollow-up plan for the developmentwork. Potential co-operation partnerswere considered to create a domesticexpert and equipment network of in-spection technology.

The results of the EB welding testswere examined at Inspecta Oy with whatis called the phased array ultrasonicmethod and at SKB’s canister laborato-ry with both the ultrasonic and radios-copy method. Destructive methods wereapplied to verify that the results obtainedwith SKB’s NDT methods were very

accurate in their resolution. The resolu-tion or the interpretation of results ofthe comparison inspections conductedby Inspecta on the same test samples didnot reach the same level at the first at-tempt, but further studies and interpre-tations have helped improve the resolu-tion of Inspecta’s inspection results aswell.

Development work on the inspec-tion methods and equipment of SKB’ssamples welded with the FSW methodwas launched in Sweden. Posiva aimsto participate in this work as well.

Posiva was involved in SKB’s de-velopment programme whose objectiveis to draw up a preliminary proposal forvalidation plans for the entire canisterproduction chain. The proposal will pro-vide a basis for a quality system to besubmitted to the authorities for approv-al and to be certified. Posiva will buildthe system on the basis of the inspectionand monitoring methods that are used asa tool for approval of the canister manu-facture or sealing. SKB postponed pre-sentation of the proposal to early 2004.

Equipment based on laser measure-ment has been developed at KungligaTekniska Högskolan (KTH) in Stock-holm to verify the accuracy of shape andmeasurement of the copper canister man-ufacture; SKB ordered the equipment forits canister laboratory in Oskarshamn.Posiva was involved in developmentwork of the equipment.

Design of the encapsulationplant and canistertransportation

A description was drawn up on the plantsite arrangements of the Olkiluoto finaldisposal facility in 2020. The descrip-tion took account of the ONKALO fa-cilities that would be built by that time.

Detailed design of the main equip-ment of the encapsulation plant contin-ued. A transfer trolley has been designedto help transfer the canister in the can-ister transfer passage of the encapsula-tion plant from one work stage to an-other, lift the canister onto the work sta-tions and even rotate it during weldingand inspection. Furthermore, an auto-matic guided vehicle has been designedin detail, which can transfer the canis-ter from the transfer trolley to the buff-er store and from there further to the lift,

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Assuring the fire safety is one of the bases for design of the canister transport vehicle.

and from the lift to the loading stationof the repository. The automatic guidedvehicle has been designed to functionso that it is not necessary to lift the can-ister more than a couple of centimetresand such that the vehicle moves so slow-ly that the canister will not fall off evenif the vehicle should stop suddenly orbump into an obstacle. Thanks to thereduction in the number of lifts, it hasbeen possible to halve the height of thebuffer store, which means the radiationprotection conditions are better thanbefore since no labyrinth shields openat the top are needed. The bridge craneof the buffer store will no longer beneeded, either.

The canister gripping device hasbeen designed to lift the canister by thelid. At the same time, a gripping devicehas been designed to enable the canis-ter to be lifted by the cylinder surface inthe event that it is not possible to graspthe lid.

In the design of the final disposalfacility, provision is also made for mal-functions and accident situations in ad-dition to normal operation. The stagesof normal operation and their durationshave been described for dose calcula-tion and to be able to identify and de-scribe the risky stages of operation in

which malfunctions may arise or thatmay lead to an accident. The descrip-tion of the Romuvaara site in Kuhmo,originally drawn up in 1999, was updat-ed to take account of the location of thefinal disposal facility at Olkiluoto anddevelopment of the plans for the finaldisposal facility.

In the current plant design, a canis-ter ready for final disposal is planned tobe transferred to the repository locatedat a depth of about 500 m with a liftalong a shaft. The consequences of anaccident where the lift falls with a can-ister were studied by canister shock ab-sorber tests. The tests showed that evena water cushion of several tens of me-tres at the shaft bottom would not suffi-ciently reduce the falling speed of thecanister, but a 20-m-thick LECA cush-ion was assessed to be a suitable shockabsorber and the canister to remain in-tact in all situations, as long as the LECAcushion does not float on the water sur-face.

Alternatively, a sealed canister canbe transferred to the repository along theinclined access tunnel with a canistertransport vehicle. In that case, the can-ister must be closed inside a transfercask of the B(U) type fitted with shockabsorbers. The transport vehicle could

be, for instance, of the same type as thecanister transfer and installation vehi-cle to be used in the repository. The heat-ing of a final disposal canister placedinside transfer and radiation-shieldingcasks during a vehicle fire occurring inthe tunnel was simulated. The studyshowed that a final disposal canisterplaced inside a transfer cask or a radia-tion shield of the installation vehicle andthe nuclear fuel contained in the canis-ter did not reach so high a temperatureduring the potential vehicle fire that theywould be damaged.

Fuel transportation

The road, rail and sea transportation al-ternatives to transport the spent fuelfrom the Loviisa plant to Olkiluoto wereupdated during 2003. In addition to ex-amination of the method of transporta-tion, routes and transfer casks, the studyof the necessary permits was updated.This time, the main emphasis was placedon assessment of the risks involved insea transportation. The study assessedthe risks posed by the transportation ofspent fuel from the Loviisa nuclear pow-er plant to the final disposal facilityplanned at Olkiluoto, both in terms oftraffic and radiation. The studied routes

18

included road, rail and sea routes orcombinations of them depending on thenecessary feeder traffic. The study in-cluded calculation of the radiation dos-es caused to the transport staff and po-pulation by normal transports and cal-culation of the radiation doses causedby any incidents and accidents to thepopulation. The risk involved in thetransportation of spent fuel caused byradiation is smaller than the ordinaryrisk posed by transportation. The ordi-nary maximal annual risks posed by thevehicle mileage in accordance with thebasic case of spent fuel transportationare 4x10-5 (by road), 2x10-4 (by train)and 9x10-5 (by ship).

Safeguards of nuclearmaterials

A preliminary technical plan was drawnup for arrangement of the safeguards ofnuclear materials in the entire area ofthe final disposal facility. Internationaldevelopment in the safeguards of nucle-ar materials was monitored by, for in-stance, participating in meetings in thisfield, e.g. in the arrangements of theExperts’ Group Meeting convened bySTUK at Olkiluoto and in Rauma.

Basic data for design of therepository and the constructionmethods

The basic data for design constitutes, toa great extent, the data required duringthe construction phase, which is utilisedin the design of ONKALO and the re-pository. Basic data is needed, for in-stance, to design the layout of the rockfacilities, and to design and implementthe excavation, reinforcement and grout-ing work. This package of tasks is di-vided into the development work linkedwith rock construction and the worklinked with design of the actual reposi-tory.

To date, rock mechanical studiesinto the repository have been conduct-ed assuming simple material models forthe rock, which are based on the contin-uous, homogeneous, isotropic, linearand elastic behaviour of rock. Of the

rock types occurring in the Olkiluotoarea, a significant proportion is foliat-ed, and the deformation and strengthproperties of the rock are anisotropic,i.e. different in different directions.Methods and ways of taking the aniso-tropic behaviour of rock into account indesign were studied during 2003. Fur-thermore, description of the mechani-cal anisotropy of the rock was examinedwith the FLAC modelling program.

In 2003, the analyses performedpertained to the effect of fracturing de-tected at the assumed final disposaldepth on the orientation and on the needfor bolting the tunnels. The work wasdone with both the KBTunnel calcula-tion code based on the block theory anddistinct element code 3DEC, whichhelped assess the effect of fracturingmore accurately by considering, e.g., therock stress prevailing at the final dis-posal depth. Posiva’s working report onthe work was completed in 2003 and theresults of the work were presented at theinternational SARA 2003 conference insummer 2003.

Posiva is involved in SKB’s APSEproject (Äspö Pillar Stability Experi-ment), in which the rock pillar betweentwo full-scale, differently pressuriseddisposal holes is fractured. The objec-tive is to verify in full scale the behav-iour of rock described with the aid ofmodels and, in particular, to establishthe effect of the backfilling support pres-sure on the failure. Another objective isto acquire practical experience of therock breaking and its detection withmeasuring devices with a view to mon-itoring the facilities during excavation.During 2003, Posiva took part in the im-plementation planning of the failure testand modelled the test by performingthermomechanical analyses with boththe FLAC3D program and the linkedFLAC2D/PFC2D program based onparticle mechanics. The PFC2D (Parti-cle Flow Code) method was employedto simulate the generation and expan-sion of fractures in fractured areas. Thepreliminary FLAC3D analyses were re-ported in SKB’s series of IPR reportspublished in 2003. The actual failure testwas launched towards the end of 2003by making the first final disposal hole.

Excavation using the drilling andblasting technique and mechanical ex-

cavation both result in a zone aroundthe repository where the rock becomesdamaged by fracturing. Owing to this,the properties of the zone differ fromthose of intact rock. The quality andextent of the damage can be substantial-ly affected by the choice of the excava-tion methods and the planning of exca-vation. During 2003, studies were con-ducted to establish the qualitative andquantitative properties of the Excava-tion Damaged Zone (EDZ) and its sig-nificance for operation of the reposito-ry. The studies concerned rock samplestaken from both the Äspö Hard RockLaboratory in Sweden and the charac-terisation tunnel at Olkiluoto. Results ofthe studies were presented, for example,at the MRS 2003 (Material ResearchSociety) conference held in Kalmar,Sweden, and at the CLUSTER confer-ence entitled “Impact of the EDZ on theperformance of radioactive waste geo-logical repositories” held in Luxem-bourg.

The project aimed at controllingseepage waters was underway from1999 to 2003 to help establish the bestmethods and techniques for sealing theOlkiluoto bedrock with a view to theconstruction phase of the ONKALO fa-cility and the design of the repository.Within the project, assessments of thewater seepage and the feasibility forgrouting of the Olkiluoto bedrock weremade for ONKALO and the repository.Olkiluoto-specific basic concepts forgroundwater control and the descriptionof disturbances were completed towardsthe end of 2003. The properties of thecement-based grouting materials weretested as part of the project.

Development work on groutingmaterials that generate a low pH is un-derway as a co-operation project of Po-siva, SKB and NUMO. The develop-ment work consists of studies into theuse of cement, slag, fly ash and silicawith additions. To ensure a tight finalresult, the objective is to develop grout-ing materials whose penetrability is bet-ter than that of cement. The develop-ment of materials with the best penetra-bility concentrates on the assessment oflong-term safety and usability of silicasol and periclase. Field tests will be car-ried out as part of the project in Finlandand Sweden.

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Development of the basicconcepts for final disposal

Posiva and SKB are jointly carrying outa long-term project (2002–2007) con-cerning the horizontal location of the fi-nal disposal canister. This basic conceptis called the KBS-3H concept, to distin-guish it from the concept in which thecanister is placed in the vertical position(KBS-3V). The installation techniqueinvolves a new type of concept in whichthe canisters and bentonite blockspacked into perforated steel drumswould be installed in about 200-m-longhorizontal disposal holes. Considerablyless rock needs to be excavated in thisconcept than in the vertical disposal holeconcept. The work is being done in sev-eral phases. The objective of the devel-opment programme is to enhance theKBS-3H concept so as to reach the lev-el of the KBS-3V concept in technicalterms, and to demonstrate the drilling ofdisposal holes and the installation of can-isters and bentonite blocks in the longhorizontal holes.

The basic design of the KBS-3Hconcept was performed during 2003using the feasibility study completed in2002. The principal areas of basic de-sign included development of the drill-ing technique of disposal tunnels, de-sign of the installation equipment of thebentonite/canister package, and assess-ment of the performance of the bento-nite plug between the packages.

As for studies into the properties ofbuffer bentonite in 2003, Posiva wasmainly involved in international co-op-eration. These projects are described inmore detail in the sections entitled “TheÄspö Hard Rock Laboratory” and“Studies on the performance of engi-neered barriers”. For the purpose of thequality assurance of buffer bentonites,the Geological Survey of Finland (GTK)studied the suitability of the differentmineralogical investigation methods forthe determination of expansive claytypes. The mineralogy of the differentbentonite deposits and commerciallyavailable bentonites was examined at thesame time.

The plans concerning the backfill-ing and sealing of the repository wereupdated during 2003 for the purpose of

preliminary design. The first phase ofSKB’s and Posiva’s joint long-term re-pository backfilling programme waslaunched. Descriptions of the differentbackfilling alternatives were drawn upand their performance with respect tolong-term safety was assessed during theyear under review. Requirements set forthe backfilling of the repository werepresented in the workshop arranged bythe OECD/NEA in autumn 2003.

It has been planned that EuropeanCa-Mg bentonites can be used for tun-nel backfilling, and Posiva is co-oper-ating with, for instance, the Czech RAW-RA to characterise montmorillonite-richclay deposits in the Czech Republic. Thestudies conducted in 2003 concerned thegeotechnical properties of the Rokla andStrance bentonites.

The Finnish Environment Instituteis co-ordinating a project with a view tostudying the performance of salt-resis-tant materials especially for the needsof road and environmental construction.Friedland clay has been included in thestudy as a reference material. Compila-tion of the final report on the project wasunderway in 2003.

Formulation of the technicalplans for the repository

The first phase of the preliminary de-sign of the repository was completed in2003. The report on the preliminary plandealt with the design concept of the re-pository, layout in the Olkiluoto bed-rock, stage-wise implementation of thefacilities, and the construction, opera-tion and sealing of the repository. Of thefunctions in the operation phase, thesafeguards of nuclear materials, radia-tion protection, normal operation andoperation in the event of incidents andaccidents have also been planned andreported.

Linked with the canister transporttechnology, new plans were drawn upfor the transport and installation vehi-cles, the consequences of a potential firedamaging the transport vehicle in therepository or the access tunnel were con-sidered, and the shock absorber to bemade at the bottom of the canister shaftwas developed. Models were made forthe repository layout in the Olkiluoto

bedrock. For some models, a descrip-tion was drawn up of how the construc-tion and sealing of the facilities couldprogress in stages during the long peri-od of operation of the repository. A re-port was drawn up on the design of therepository and the most common tech-nical constructions of the facilities weredocumented. Foreign materials remain-ing in the repository after sealing wereassessed as well. Separate descriptionswere drawn up of the repository systemsand operations in the operation phase.Heat generation by the canisters and therestrictions placed on the maximum tem-perature have a fundamental effect onthe repository designs. Thermal analy-ses were carried out for the facilities,utilising the most recent data on, for in-stance, thermal conductivity measure-ments of the bedrock.

The repository can be built on oneor several levels. The preliminary plancomprises the facility alternatives placedon one level and on two levels. The plansfor the repository were presented in theform of layout in the Olkiluoto bedrock.The total excavation volume of the re-pository is some 1.3–1.4 million cubicmetres. Since the facilities will be exca-vated and backfilled in stages during theperiod of repository operation, the vol-ume open at a given time will be some0.5 million cubic meters. An access tun-nel with a steepness of 1:10 and verticalshafts will provide connections betweenthe underground facilities and the groundsurface. The central tunnels of the repos-itory will be implemented on what iscalled the parallel tunnel principle, inwhich two parallel central tunnels arelinked to each other by means of con-necting tunnels located at fixed intervals.The parallel tunnel principle improvesthe fire safety of the facilities and pro-vides a flexible opportunity to backfilland seal disposal tunnels in stages dur-ing the period of repository operation.

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The principle of the repository in the one-layer alternative after the final disposal operations of about 30 years.A = Disposal tunnels, B = Central tunnel, C = Access tunnel, D = Passenger shaft, E = Canister shaft and F = Ventilationraise.

A

B

CD E

A building permit in accordance with the Building Act was granted for the ONKALOfacility on 12 August 2003.

F

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DESIGN ANDCONSTRUCTIONOF THE ONKALOFACILITY

Design of the undergroundrock characterisation facility

Before a decision to construct a reposi-tory is taken, supplementary bedrockinvestigations will be carried out at Olki-luoto for the implementation design ofthe facilities. An underground rock char-acterisation facility, known as ONKA-LO, will be constructed for the investi-gations and design. The construction isscheduled to begin during 2004.

ONKALO should be constructed toallow underground investigations forsite confirmation without jeopardisinglong-term safety of the repository site(Posiva 2000). In addition, it should bepossible to later link ONKALO to therepository so as to form a part of it.

In the preliminary design phase ofONKALO in 2001, the alternatives thatincluded at least two separate accessroutes were considered feasible in termsof operational safety. In the draft designphase in 2002, two alternative draft de-signs were drawn up on the basis of the

preliminary design: the shaft alternativeand the access tunnel alternative. Afterthe evaluation, the access tunnel alter-native was chosen as the basis for fur-ther development of the ONKALO fa-cility owing to, for instance, the higherflexibility, the greater feasibility for in-vestigations and the better working con-ditions.

The main drawing phase ended withsubmission of the application for abuilding permit to the municipality ofEurajoki on 20 May 2003. This outlinedimplementation plan material was sentto STUK for evaluation. In the licencematerial, the location of the ONKALOfacility was confirmed to be south of theKorvensuo basin.

The implementation design phasebegan after the granting of the buildingpermit (12 August 2003). Plans and sup-ply documents were drawn up for the in-vitation for tenders for the first tunnelcontract. The facilities, volumes andquality were determined on their basisfor submission of the tender. The firsttunnel contract includes excavation andstructures of the access tunnel (to level–417 m) near the main characterisationlevel and raise boring of the shaft to lev-el –287 m. The invitations for tenderswere sent to the excavation contractorson 21 November 2003.

Construction above ground

The purpose of area planning aboveground is to reserve sufficient areas androutes necessary for the repository forspent nuclear fuel and for the operationsthat prepare its implementation. In2003–2004, the area planning projectsare primarily linked with the construc-tion of ONKALO.

In 2003, the area planning concen-trated on the planning of a general lay-out of the ONKALO area (roads, siteareas), the heating, plumbing and elec-tricity trunk routes of municipal engi-neering and the support building forfield studies to be built for investigationpurposes. Earth works of the municipalengineering conduit began towards theend of 2003. A building permit wasgranted for the support building for fieldstudies on 9 December 2003.

In 2004, the area planning and con-struction will concentrate on implemen-tation of the facilities and structuresnecessary for the tunnel excavation ofONKALO.

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INTERNATIONALCO-OPERATION

A significant proportion of Posiva’s re-search, development and technical de-sign work is conducted under bilateralor multilateral international jointprojects. In the development of encap-sulation and final disposal technology,Posiva mainly co-operates with theSwedish SKB, and a large part of thiswork was done at the Äspö Hard RockLaboratory (see the following chapter)and at the canister laboratory in Oskar-shamn. Research that supports the as-sessment of long-term safety is current-ly conducted to a great extent under theframework programmes of the Europe-an Commission, the sixth of which isbeing launched. Furthermore, Posivahas extensive connections with nuclearwaste programmes in other countriesthrough either international organisa-tions (OECD/NEA, EDRAM) or bilat-eral agreements. Posiva signed a newmemorandum of understanding on co-operation with the United States’ De-partment of the Environment (DOE).

The Commission’s fifth frameworkprogramme has included a number ofjoint studies, which involved taking ajoint stand or procedure with a view tofacing future challenges posed by nucle-ar waste management. In theNET.EXCEL study, the implementationorganisations of nuclear waste manage-ment assessed the current status of finaldisposal studies, prioritisation of thestudies and enhancement of the futureopportunities for networking. A reporton the studies is being completed in thefirst part of 2004. Another similar groupconsidered the long-term monitoring offinal disposal, its technical opportunitiesand implementation methods in the lightof current knowledge. This report is be-ing completed in the first part of 2004as well.

Posiva also supported the organisa-tion of international seminars and con-ferences by being involved in their prep-aration and implementation. In additionto the previously mentioned workingmeeting of the OECD/NEA, which stud-ied engineered barriers, Posiva support-ed the EDZ meeting arranged by the ECin Luxembourg and took part in thepreparation of the OECD/NEA seminaron the handling of risks and uncertain-ties, which is held in the first part of2004.

The Äspö Hard RockLaboratory

SKB and Posiva mostly operated with-in the co-operation framework as in pre-vious years. In addition to this, severaljoint projects were launched or plannedduring the year, which are not directlyincluded in the co-operation programmeat Äspö, but in which it will be possibleto utilise the Äspö Hard Rock Labora-tory or the ONKALO facility for mak-ing demonstrations in the future. Thesejoint projects include, for instance, de-velopment work on the KBS-3H con-cept, development work on the low-pHcement and the joint project on back-filling technology (further informationon the above-mentioned projects under,e.g., “Final disposal technology”).

At Olkiluoto, Posiva is mainly con-centrating on research into the bedrockconditions and into the assessment ofsite-specific or site-dependent factors.General development of the rock con-struction methods for the repository canalso be implemented in ONKALO. AtÄspö, it is performing the general veri-fication and demonstration of operationslinked with engineered barriers and fi-nal disposal technology. Field tests thatprovide a basis for the assessment oflong-term safety are carried out at Äspölinked with the performance of the bed-

rock as a natural barrier.The investigations to be carried out

at the Äspö Hard Rock Laboratory with-in the framework of international co-operation have been grouped as follows:

– investigations linked withtechnology

– investigations linked withgeosciences

– investigations linked with naturalbarriers

– investigations linked withoperations of the researchinstitute.

The COLLOID project was launchedat the Äspö Hard Rock Laboratory in2000 to examine the stability and mo-bility of colloids. During 2003, theproject focused on studying the role ben-tonite plays in forming colloids. Thefield tests linked with the project werecarried out in both the Äspö characteri-sation tunnel and the VLJ Repository atOlkiluoto. The amount and quality ofcolloids occurring in the natural state inthe groundwaters at Olkiluoto were alsoinvestigated during the field test. Theinvestigation results will be reported in2004.

Posiva was involved in the tasks ofthe Task Force aimed at studyinggroundwater flow and migration. Thepurpose of Task 6, which was performedduring 2003, was to combine the siteevaluation and modelling processeslinked with the migration of fluids infractured rock on the scale of 50 m to100 m. From Posiva’s point of view, itis highly useful to explore the compati-bility of the results of site characterisa-tion with the modelled migration paths.The project utilises test results obtainedfrom previous work packages by mod-elling the migration in certain fracturesystems. The practical modelling workwas conducted at the Technical Re-search Centre of Finland (VTT).

The objective of the large-scale (10–50 m) TRUE Block Scale test was to

23

provide deeper insight into groundwa-ter flows and the migration of the tracerin the fracture network. The secondphase of the test, TRUE Block Scalecontinuation (TBS2), concentrated onestablishing the retention and sorptionproperties of a structure that containssmectite. The test consists of model-ling and tracer tests during 2003 and2004.

Posiva is involved in the “PrototypeRepository” project, which is imple-mented at SKB’s Äspö Hard Rock Lab-oratory. The project has been acceptedinto the EU’s framework programme for2000-2003. The KBS-3 final disposalconcept is being tested and demonstrat-ed in the project by constructing a full-scale long-term test for a sealed final dis-posal tunnel. During 2001, canister mod-els fitted with heaters and surrounded bycompacted bentonite were placed in fourfull-scale final disposal holes. In addi-tion, the tunnel was equipped with in-strumentation, and a sampling systemwas also installed. Finally, the tunnel wasfilled with a mixture of crushed stone andbentonite, and closed by a solid concretestructure. In 2003, canisters were in-stalled in the tunnel section of the sec-ond phase in two final disposal holeslined with bentonite and the open tunnelsection was filled with a mixture ofcrushed stone and bentonite.

Posiva is involved in the LOT test(Long-Term Test of Buffer Material) tobe carried out at the Äspö Hard RockLaboratory. The test pertains to validat-ing the hypotheses and models of long-term processes occurring in the buffermaterial, and the closely linked processesconcerning microbiology, the migrationof radionuclides, copper corrosion andthe migration of gas. The tests are per-formed at a depth of about 500 m, inboreholes drilled in the tunnel bottom;the boreholes have a diameter of 30 cmand a depth of 4 m. The tests to be per-formed in five boreholes were begun in

1999, and they have been planned to lastfor 1, 5 and 20 years.

Posiva and SKB jointly launched thefirst phase of the project linked withbackfilling of the repository. The objec-tives of the first phase were to describethe optional backfilling methods that hadbeen determined together and to assesstheir performance from the viewpoint ofthe requirements; to select the most fea-sible methods for further developmentand to assess the volume of the requiredresearch and development work beforecommissioning of the repository. Thefirst phase consisted of the followingwork packages: a description of the cur-rent technological development level,studies into the clay materials as part ofthe backfilling, preliminary plans fordevelopment of the backfilling technol-ogy, a description of the backfilling con-cepts, the role packer structures play inthe repository, assessment of the optionalbackfilling methods and planning of afollow-up programme.

Posiva was involved in SKB’sAPSE project (Äspö Pillar StabilityExperiment), whose purpose is to carryout a large-scale failure test on the pil-lar between two final disposal holes.

The objectives of the work are:– to test the opportunities for

predicting the strength behaviourof crystalline, hard rock on thetunnel scale and in an intensestress field using numericalmodelling programs FLAC3Dand PFC2D. In addition, thelinked program FLAC2D/PFC2Dwas applied as a completely newone.

– to acquire practical experience inthe monitoring of rock damageusing, for instance, acousticemission (AE) measurements andto compare the measuredresponses with the modelledresults. AE is a highly feasible andinteresting method to use during

construction of the ONKALOfacility as well.

– to demonstrate and furtherimprove opportunities to controlgrowth of the EDZ zone. The testwill examine the effect of thepressure prevailing in one hole onthe propagation of fractures.

During 2003, Posiva took part in thepractical implementation and design ofthe failure test. In addition, Posiva wasinvolved in the excavation project of theAPSE tunnel, which also investigatedissues linked with the feasibility forgrouting and the effect of blasting dia-grams on the excavation result. The fail-ure test was modelled by performingthermomechanical analyses with boththe FLAC3D program and the linkedFLAC2D/PFC2D program. The prelim-inary FLAC3D analyses were reportedin SKB’s IPR series of reports publishedin 2003. A report on the detailed analy-ses was completed in early 2004. Theactual failure test was launched at theend of 2003.

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MANAGEMENT OF OPERATING WASTE

Operating waste produced at the Olkiluoto Power PlantTotal volume of waste In the VLJ Repository

KAJ Silo MAJ Silo(pcs) (m3) (pcs) (pcs) (m3)

Bituminised waste 6953 1391 6703 1341Other operating waste– in drums 6142 1092 5880 1041– in steel containers 455 632 5 450 632– in concrete boxes 174 904 2 172 904– unpacked 316Total 4335 3918

In addition to high-level spent fuel, theOlkiluoto and Loviisa Power Plants pro-duce intermediate- and low-level nucle-ar waste, comprising used reactor inter-nals (e.g., control rods and core instru-ments) and plant operating waste (e.g.,ion-exchange resins and miscellaneousmaintenance waste). The managementof used reactor internals is discussed inthe section entitled “Decommissioninginvestigations”. The management ofoperating waste is discussed below.

OLKILUOTO POWERPLANT

Principles and schedule

Most of the operating waste is packagedimmediately for handling, storage andfinal disposal. The intermediate-levelion-exchange resins used to clean theprocess water are solidified into bitu-men, and the mixture is cast into steeldrums. Some of the low-level waste(compressible miscellaneous mainte-nance waste) is compacted into the steeldrums with a hydraulic press, and some(metal scrap and filter rods) is packedas such into steel containers, concreteboxes and steel drums. Drums contain-ing compressible waste are further com-pacted so that the final height of thedrums is approximately one half of the

original (the diameter, however, does notchange). Metal scrap can also be com-pacted before packaging. Miscellaneousliquid waste and sludge are solidified bymixing the waste and a binding agent ina drum that serves as a package for thesolidified mixture.

Operating waste is stored tempo-rarily at the plant units, in the storagefacility for intermediate-level waste(KAJ Store), in the storage facility forlow-level waste (MAJ Store), in the en-closed storage area and, to a minor ex-tent, in the KPA Store, at the Olkiluotoplant site.

Intermediate- and low-level wasteproduced during power plant operationis disposed of in the present waste silosof the repository for operating waste(VLJ Repository). Very low-level wasteis exempted from regulatory control andis either transported to the dump at theOlkiluoto plant site or handed over, forexample, to be processed for reuse.

Current status of storage andfinal disposal

The table below shows the current sta-tus of storage and final disposal at theend of 2003. The waste has been packedinto drums (200 litres each, or about 100litres in compacted form), steel contain-ers (1.3 or 1.4 m3 each) and concreteboxes (net 5.2 m3 each). In addition,

Studsvik Energiteknik AB held fivedrums of low-level ash generated in anincineration test in their storage facilityin Studsvik, Sweden. If necessary, thedrums and containers are stored in thestorage facilities of the plant units andthe KAJ Store before final disposal inthe VLJ Repository. Before transfer tothe VLJ Repository, the drums and steelcontainers were placed in large (net 5.2m3 each) or small (net 3.9 m3 each) con-crete boxes, the large boxes housing 16drums or 7 drums and 2 steel contain-ers, and the small boxes 12 drums. Cor-respondingly, the concrete boxes willhouse twice as many compacted drums.

Bulky contaminated metal compo-nents are stored in the KAJ Store andthe adjoining enclosed storage area. Inaddition, unpacked operating waste,such as used ventilation filters and non-bituminised resins, are stored at the plantunits, and waste oil in the KPA Store.Some of the metal scrap will be disposedof as such in the concrete boxes used inthe VLJ Repository. Some of the un-packed waste will later be exempt fromregulatory control and will either be re-used or transported to a dump. For ex-ample, very low-level waste oil may beexempt and reused. At the end of 2003,the amount of such waste oil was 13 m3.

The waste storage facilities of thepower plant units can house some 1 000drums each. The MAJ Store mainlyhouses only very low-level maintenance

Total

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waste bags and scrap, which will be ex-empt from regulatory control. The KAJStore can house drums, containers andbulky, contaminated metal components,the total volume of which comprisessome 6 000 drums. The capacity of theintermediate-level waste silo in the VLJRepository is 17 360 drums (200 litreseach) and that of the low-level waste silo24 800 drums, i.e. about 8 400 m3 ofoperating waste packed in drums, orthe equivalent of the waste accumu-lated during 40 years of operation of thetwo power plant units at Olkiluoto. Ad-ditional repository facilities can be builtin the same bedrock area, if necessary.

Radioactive wastes from small pro-ducers are stored in the VLJ Repositoryat Olkiluoto. STUK Radiation and Nu-clear Safety Authority has so far beenin charge of these wastes, which consistof radioactive material used mainly inhospitals, research institutes and indus-trial plants. By the end of 2003, 42 m3

of this waste had accumulated in the VLJRepository.

Studies on operating waste

A large-scale test of the microbiologi-cal degradation of low-level mainte-nance waste is being conducted in theconstruction tunnel of the VLJ Reposi-tory. The project was launched as partof the PROGRESS project of the EU’s

nuclear fission safety programme in1997. These studies are conducted todetermine more exact estimates of thevolume of gases generated by mainte-nance waste, and in order to gain a bet-ter understanding of the entire degrada-tion process under the conditions thatcorrespond to the situation after the seal-ing of the VLJ Repository. This projectalso involves monitoring the migrationof activity from the waste drums to thesurrounding water. One concrete boxfrom the VLJ Repository with drumscontaining compacted waste was placedin a 20 m3 steel tank. When the air orig-inally found in the drums had been letout, the amount of the generated gas wasfound to be low compared with the val-ue used in the safety analysis. Themonthly rate of gas generation is 50 to100 dm3, whereas the value used in theFSAR safety analysis of the VLJ Re-pository was some 900 dm3/month,when proportioned to the scale of thetest.

Hydrochemical, microbial and gasanalyses show that the test conditionsare clearly reducing. Methane continuesto dominate the gas phase. The condi-tions prevailing outside the drums, at thebottom of the test tank, on the lid levelof the drums and inside the drums dif-fer considerably. The pH outside thedrums is about 9 while it is neutral andeven slightly acid inside them. The

DGGE (Denaturing Gradient Gel Elec-trophoresis) method was tested to iden-tify the main microbe species. How-ever, the small amount of reference dataon the nucleotide sequence hinderedidentification of the species.

The studies are progressing in ac-cordance with the research plan revisedin 2003 in such a way that the focus ofsampling has shifted to inside the drums.

Studies during the operatingperiod of the VLJ Repository

Operation-time monitoring of the VLJRepository (rock mechanics, hydroge-ology, groundwater chemistry, reposito-ry air) continued in 2003 in accordancewith the research and monitoring pro-gramme drawn up previously. The wa-ter quality at the groundwater stationsof the VLJ Repository at Olkiluoto hasbeen monitored since the latter part ofthe 1980s.

In spring 1993, ten test bolts wereinstalled in the research tunnel of theVLJ Repository at Olkiluoto to estab-lish the corrosion rate of the bedrockbolts. The objective of the test is to ob-tain information on the corrosion resis-tance of galvanised reinforcement boltsin the bedrock under the conditions ofthe VLJ Repository at Olkiluoto, withthe hypothesis of the cement mortar thatprotects the bedrock bolts completely

26

Operating waste produced at the Loviisa Power PlantTotal volume of waste Share of the

storage capacity ActivityAt the plant/in the storage In the

building repository(m3) (m3) (%) (GBq)

Spent ion-exchange resins 434,5 51 14901Evaporator concentrates 738 70 451Maintenance waste 332,4 1180 487Total 1504,9 1180 15839

losing its protective property. The firsttest bolt was removed by core drillingin 1996. The next bedrock bolt will beremoved for testing in 2004.

Since the bedrock bolts had re-mained unchanged, support tests werelaunched in 1998 to study the corrosionbehaviour of galvanised steel in theborehole of the bedrock bolt removedfrom the research tunnel (“Bolt 7”). Thingalvanised steel plates and concrete cy-linders were installed in the borehole,thus seeking to regulate the groundwa-ter pH so as to make it more alkaline,and thereby simulating the actual envi-ronment of the reinforcement bolts inthe operating conditions. Since the wa-ter chemistry in the above borehole hasnot been stable and the corrosion rateof the samples was contrary to expecta-tions, a decision was taken to transferthe samples to the borehole located inthe construction tunnel (VLJ-KR9). Thewater chemistry and conditions of thenew disposal hole were studied in spring2002, and 18 new zinc-coated steelplates and 16 zinc plates were installedin the borehole with the concrete cylin-ders in September 2002. In the autumnof 2003, samples were taken from theone-year-old test samples. The resultsof their analyses showed that the corro-sion rate had been extremely slow.

LOVIISA POWERPLANT

Principles and schedule

Intermediate- and low-level operatingwaste is conditioned and stored at theplant site. Spent ion-exchange resins andevaporator concentrates are stored tem-porarily without solidification in a tankstorage facility.

Compilation of the preliminarysafety analysis report (PSAR) of a ce-mentation-based solidification plantbegan towards the end of 1997. The pre-liminary safety analysis report was sub-mitted to STUK for approval in the be-ginning of 2000 and it was approved inthe spring of 2001. Preliminary designof the solidification plant began in 2002and the implementation design towardsthe end of 2003. The solidification plantis scheduled for completion at the endof 2006.

Fortum has invested heavily in thedevelopment of new waste-treatmentmethods. These efforts have resulted ina waste-treatment method that separatescaesium from the evaporator concentrateand reduces the waste to a very smallvolume. The evaporator concentrate isthen so clean that a larger volume than

previously can be exempt from regula-tory control without increasing the an-nual activity release.

Dry maintenance waste from powerplant service and repair work is packedin steel drums of 200 litres each. Com-pressible waste is compacted into drumswith a hydraulic press, thereby reducingthe volume by a factor of 3 to 4.

Intermediate- and low-level operat-ing waste from the Loviisa Power Plantwill be disposed of in an undergroundrepository built in the bedrock at thepower plant site. The repository was putinto operation as an interim store in thespring of 1997. The repository receivedan operating licence in the spring of1998, and the repository has been usedfor the final disposal of maintenancewaste since the summer of 1999.

Current status of storage

The table below shows the current sta-tus of storage and final disposal at theend of 2003.

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The final disposal facility

Intermediate- and low-level operatingwaste produced at the Loviisa PowerPlant will be disposed of in a repositoryconstructed in the bedrock of Hästhol-men Island. Fortum has been conduct-ing studies on the suitability of the bed-rock in the power plant area for the fi-nal disposal of waste since the early1980s. A preliminary safety analysis re-port on the final disposal facility wascompleted in 1986. In 1988, STUKRadiation and Nuclear Safety Authori-ty approved the safety analysis reportand granted permission, in accordancewith the power plant operating licence,for the construction of a repository. Pre-paratory construction activities began in1992, and construction started in Feb-ruary 1993.

Excavation work begun in spring1993 was completed on schedule inDecember 1995. Construction and in-stallation work was started in Novem-ber 1995. The installation work wascompleted on schedule in late 1996, atwhich time an application for the oper-ating licence of the repository was alsosubmitted. The repository was put intooperation as an interim store in spring1997 and as a final disposal facility insummer 1999.

The final repository comprises atransport tunnel of about 1 100 metresin length, tunnel and hall spaces built at

a depth of about 110 metres, and stairand ventilation shafts. The constructionof the repository is implemented in twostages. During the first constructionstage, all repository spaces and accessroutes were excavated. These includedtwo final disposal tunnels for mainte-nance waste and a final disposal hall forsolidified waste. Only one maintenancewaste tunnel and the systems serving theentire repository were completed dur-ing this stage. During the second stage,construction and installation work relat-ing to the second maintenance wastetunnel and to the room for solidifiedwaste will be carried out. The implemen-tation time of the second stage is deter-mined by the building schedule of thesolidification plant, which is scheduledfor 2004–2006.

Separate research programmes havebeen planned for the study of the trans-port tunnel and hall areas during opera-tion.

Caesium separation facility

By the end of 2003, a total volume ofover 1 100 m3 of evaporator concentrateswas treated at the caesium separationfacility with 20 ion-exchanger columns,each with a volume of 8 litres. The effi-cient separation of caesium from evapo-rator concentrates is a normal operatingprocedure at the power plant.

Studies on solidificationmethodsSolidification with cement has been se-lected as the basic conditioning methodfor Loviisa’s wet operating waste. Veri-fication of the solidification recipes forbottom deposits and ion-exchange res-ins with new building cements contin-ued and the test results on the solidifica-tion products of ion-exchange resinswere reported during the year under re-view. In addition, test data was obtainedfrom solidification product samples inlong-term storage, the oldest of whichare now as old as 20 years.

Owing to the entry into force of theEuropean cement standard and, at thesame time, to the modification made bythe only Finnish cement manufacturerin the burning process, grinding andraw-material base of the cement clinker,the Finnish building cement types havechanged considerably. As a result of thedevelopment work, which comprisedmaterials tests, preliminary tests andactual solidification tests, the solidifi-cation formulations of the waste havebeen verified in such a way that the prop-erties of the fresh and hardened endproduct fulfil the requirements set.

The durability test on ion-exchangeresins solidified in half-scale containersin 1987 continued and the test resultswere reported in 2003. For 16 years now,the waste containers have been im-

28

mersed in tanks filled with groundwa-ter at the Loviisa Power Plant; as ex-pected, they are still in good condition.No damage to the concrete walls of thecontainers has been detected, and thecomposition of the groundwater has re-mained relatively stable. Activity mea-surements for the groundwater have notindicated any signs of nuclide releasefrom the solidification products in theconcrete containers.

Studies during the operatingperiod of the VLJ Repository

Operation-time studies on the reposito-ry for operating waste (VLJ Reposito-ry) continued in 2003 in accordancewith the monitoring programme. Theobjective of the programme is to studyand monitor long-term changes in theproperties and the behaviour of thegroundwater and bedrock in the reposi-tory and in its immediate vicinity.

The monitoring programme includ-ed monitoring the groundwater table inthe investigation holes above groundonce a month. The location of fresh andsaline groundwater in the holes wasmeasured four times during 2002. In therepository, the conductivity and pressureof groundwater, and the amount of seep-age water were measured once a month,with the measurement of pressure andthe amount of seepage water being part-ly continuous. The measurements con-centrated on seepage water pools andon five groundwater stations built espe-cially for this purpose. The hydro-geochemical research programme in-cluded water sampling and analysis fromgroundwater station LPVA2. Comparedwith the previous years, there were nosignificant changes in the results. Thestability of the bedrock was mainly mon-itored by an automatic rock mechanical

measurement system. Visual checking ofthe excavated and reinforced rock sur-faces for maintenance purposes alsocontinued in 2003.

According to the findings of 2003,the groundwater table follows variationsin the sea-water level fairly closely.During construction, the groundwatertable lowered a few metres in the im-mediate vicinity of the repository, but adistinct rise was observed after comple-tion of the repository. Owing to the drysummer, however, the groundwater ta-ble lowered slightly. The interface be-tween fresh and saline groundwater wasbetween the levels of about -10 and -80m in the repository area, in other words,distinctly above the repository.

The electrical conductivity measure-ments of seepage water show that theseepage water is slightly fresher than inthe previous year, with the conductivityvarying between 700 and 1 300 mS/min different parts of the repository.

The pressure values of the ground-water clearly reflect the effect of varia-tions in the sea-water level. At the fivegroundwater stations, the pressure var-ies between 1 and 11 bar as in the previ-ous years.

The amounts of seepage water weremeasured at seven points on differentsides of the repository. After completionof the excavation in 1996, the totalamount of seepage water was about 300l/min at its highest, from which it hassteadily reduced, and was about 110 l/min at the end of 2003. About half ofthe seepage water comes from the trans-port tunnel and the rest from other fa-cilities. The measurement results showthat the maintenance waste rooms arepractically dry.

The preliminary results of rock me-chanical measurements suggest very sta-ble conditions. As in the previous years,the displacements that have taken place

Safety of final disposal ofoperating waste

With regard to the final disposal of op-erating waste, the activities during theyear under review consisted of monitor-ing the international development bymeans of a conference visit and tradejournals. The comparison of the sorp-tion parameters used for the safety anal-ysis of the Loviisa repository, which wasconducted as part of the decommission-ing investigations, and the corrosionstudies and studies into filling materi-als also contribute to the readiness forthe safety analysis of the final disposalof operating waste.

JOINT STUDIES

The long-term durability of concreteunder final disposal conditions is beingstudied as a joint project by TVO andFortum in the VLJ Repository at Olki-luoto and at the Materials and ConcreteLaboratory of Contesta Oy (formerlyowned by Fortum Technology). The re-search project pertains to both the op-erating waste and decommissioningwaste management. The studies are dis-cussed in the section entitled “Decom-missioning investigations” (Page 29).

in the repository ceilings and walls arevery small, distinctly of the order of lessthan 0.1 mm. Visual examinations alsoshow that the repository is in good con-dition, and the subsurface drains performas intended.

29

DECOMMISSIONING INVESTIGATIONS

OLKILUOTO POWERPLANT

Used reactor internals, which are clas-sified as being intermediate-level oper-ating waste, will not be disposed of un-til during the decommissioning of theplant. The used reactor internals arestored in the pools of the plant units anda separate inventory is kept of them. Bythe end of 2003, for instance 255 con-trol rods, 217 core instruments, two coregrids and two moderator tank lids withtheir steam separators had accumulatedat the Olkiluoto Power Plant.

The decommissioning plan for theOlkiluoto Power Plant was updated dur-ing the year under review. According tothe decommissioning plans, the reactorpressure vessels of the power plant unitswill be removed and disposed of in onepiece. The plans are based on a powerplant unit operating period of about 40years and on controlled storage of about30 years before decommissioning. Thefinal decommissioning plan will bedrawn up well before the power plantunits cease energy generation. Accord-ing to the present plan, the intermedi-ate- and low-level waste from the de-commissioning and the used reactor in-ternals from power plant operation willbe disposed of in an extension of theVLJ Repository.

The decommissioning investiga-tions are aimed at technical and econom-ic development of the decommissioningplan and specification of the basic datafor the safety assessment of final dis-posal.

Activity measurements of varioussystems within the plant were continuedas a means of further developing the ac-tivity inventory of the power plant’s de-commissioning waste. The updated in-ventory of activated material was com-pleted at the end of 2003. In the updated

decommissioning plan, its results haveonly been used in the dismantling planfor the thermal insulation plates and bi-ological shields that surround the pres-sure vessels. Design was completed con-cerning the reactor’s biological shield,thermal insulation plates and decommis-sioning of the fuel pools in the event ofthe reactors being removed in one piece.A new method of dismantling based ondiamond wire cutting is employed in thenew plan. The database built as a partof the decommissioning plan for thecontaminated plant section, which wascompleted in 1989, was transferred toanother database application. The data-base helps calculate the amounts ofmaterials, the amounts of radioactiveisotopes, the working hours required fordismantling, dose rates and committeddoses of the workers, and the costs.

Long-term corrosion tests of carbonsteel began towards the end of 1998 inthe construction tunnel of the VLJ Re-pository. The tests are performed joint-ly with the concrete research in such away that some of the pieces of carbonsteel are placed in the same borehole asthe test samples of concrete. Laborato-ry tests in the concrete-water and bed-rock-groundwater environments werelaunched in spring 1998. The corrosionrate of the carbon steel samples is de-termined by the loss in weight and bythe volumetric measurement of hydro-gen gas. The planned periodic samplingand measurements of the laboratory andfield tests were carried out in 2003. Theblack deposits detected (in the concretetest samples and carbon steel samplesand the water) during the studies con-ducted in the VLJ Repository at Olki-luoto over several years have been foundto contain, for instance, sulphate-reduc-ing bacteria, which have been assessedto cause a higher corrosion rate than ex-pected.

LOVIISA POWERPLANT

Operation of the Loviisa Power Plantresults in the accumulation of interme-diate- and low-level nuclear waste thatwill not be disposed of until during thedecommissioning of the plant. Thiswaste includes, e.g., used shielding ele-ments, absorbers, neutron flux transduc-ers, intermediate rods of control rodsand fission chambers.

By the end of 2003, 146 usedshielding elements, 199 absorbers, 195neutron flux transducers, 128 interme-diate rods and nine fission chambers hadaccumulated at the Loviisa Power Plant.Of these items, the shielding elementshave been placed in the plant pools inthe spent fuel store, and the absorbersand fission chambers have been storedin specially built channels in the spentfuel store. The neutron flux transducersand intermediate rods have been storedin corresponding channels located in thereactor halls.

In 1987, Fortum drew up a plan andcost estimate for the decommissioningof the Loviisa Power Plant. The decom-missioning plans were updated in 1993.The plan was based on 30 years of com-mercial power plant operation, which isequivalent to the designed technical lifeof the power plant. However, technicalmeasures may be undertaken to extendthe operational life of a nuclear powerplant. New studies were completed atthe end of 1998, which focused on theeffects of revised spent fuel managementand the power plant modernisationproject on the decommissioning plansand schedules. The operational life ofthe power plant has also been plannedto be extended to 45 years, and this wasconsidered in the studies. According tothe updated decommissioning plan, allthe radioactive systems not necessary for

30

the remaining nuclear operation (i.e.storage of the spent fuel, solidificationof the wet waste and final disposal oflow- and intermediate-level waste) atHästholmen will be dismantled imme-diately after the shutdown of the powerplant.

The plans are revised every fiveyears. The new decommissioning planwas updated during the year under re-view. An operational life of 50 years waschosen as the basis for the updating. Theupdating consisted of the verification ofthe activity inventory, dismantling mea-sures, radiation dose estimates, amountsof the components and packages to bedisposed of, safety of the final disposal,and estimates of the workload and costs.

It is not expedient, however, to makeany decisions regarding decommission-ing or continued operation until towardsthe end of the designed technical opera-tional life. It is also advisable to take afinal stand on whether the plant will bedecommissioned immediately or after acertain delay, just upon termination ofthe power plant operation, before thebeginning of the decommissioning.

JOINT STUDIESThe long-term durability of concreteunder final disposal conditions is beingstudied as a joint project by TVO andFortum in the VLJ Repository at Olki-luoto and at the Materials and ConcreteLaboratory of Contesta Oy at Myyrmä-ki, Vantaa. The research project origi-nally co-ordinated by Posiva concernsboth the operating waste and decommis-sioning waste management. In 2003,TVO assumed responsibility for co-or-dination of the project. The purpose ofthe studies is to realistically assess thelong-term behaviour and degradation ofconcrete in the bedrock-groundwaterenvironment that corresponds to oper-ating conditions. The objective is to es-tablish, using modern concrete technol-ogy, the durability and lifespan of theplanned concrete types with differentcompositions under the real final dispos-al conditions and under accelerated lab-oratory conditions. Special emphasis willbe placed on establishing the most dura-ble concrete compositions under prevail-ing conditions, which will meet the re-quirements set for the lifespan.

The field and laboratory tests werebegun in 1998. During 1999-2003, theresearch conducted annually includedperiodic water chemistry analyses ofstorage solutions of the test samples and

groundwater in the boreholes. Periodicanalyses of the test samples with respectto the penetration depth of corrosivecomponents were carried out in 1999,2000 and 2002, and analyses of the mi-crostructures in 2001 and 2003. Further-more, microstructural maps were deter-mined for the nine concrete types testedat the laboratory, and microbes wereanalysed during the field test samplingfrom the surface of the concrete test sam-ples and water in 2003. The black de-posits formed on the test samples con-tained sulphate-reducing bacteria (SRB),whereas very few SRB were detected inthe water samples. Before being reinsert-ed to the borehole, the concrete test sam-ples were washed owing to their blackdeposits. In 2002, geochemical data onthe bedrock groundwaters of the reposi-tory for operating waste at Hästholmenand the VLJ Repository at Olkiluotowere compared with respect to the long-term durability of concrete, particularlywith respect to concrete-corroding com-ponents and microbial activity. On thebasis of the tests it was assessed that dif-ferences between the groundwaters wereso small that it would not be necessaryto begin field tests at Hästholmen.

The tests will continue in accor-dance with the updated research planincluded in the summary report pub-lished in early 2004.

31

REPORTING, COMMUNICATIONS ANDCONTACTS

A total of eleven reports were publishedin the Posiva series of reports in 2003. Alist of these reports is appended. In ad-dition, company-specific reports dealingwith the research results were published.

In Finland, close co-operation con-tinued with the research institutes, uni-versities and consulting firms engagedin studies on nuclear waste management.During the year under review, the Min-istry of Trade and Industry and STUKRadiation and Nuclear Safety Authori-ty, as regulatory authorities, were keptinformed of the measures taken in nu-clear waste management and of theprogress made in research.

Lectures were held in Finland atmeetings intended for both experts andthe general public. Representatives fromthe power companies and from Posivaparticipated as experts in the work con-ducted by the leading and joint groupsof the publicly financed nuclear wastemanagement research programme.

As regards communications duringthe year under review, the main empha-sis was placed on issues related to theconstruction of ONKALO and to finaldisposal technology.

In spring, a press conference wasorganised at Olkiluoto concerning the

submission of an application for a build-ing permit for ONKALO. A brochureabout the construction of ONKALO andthe final disposal project was publishedin Finnish, English and Swedish in au-tumn.

Natural analogues and technologyof the final disposal were demonstratedat the exhibition mounted as a part ofthe Yläne Nature Cabinet during thesummer. More than 3 000 people visit-ed the exhibition.

The welding and inspection tech-nology of the final disposal canister lidwas demonstrated to a group of journal-ists from the Satakunta area during avisit to SKB’s canister laboratory in Os-karshamn. During the visit, the groupalso became acquainted with the inves-tigations that were underway at the ÄspöHard Rock Laboratory.

In early 2004, an information meet-ing was arranged for journalists from theSatakunta area concerning the design ofthe final disposal project and implemen-tation of the final disposal at Olkiluotoon the basis of the plant description.

International interest in Posiva’soperations was manifested in the greatnumber of foreign visitors. More than40 foreign groups visited Olkiluoto to

become acquainted with Posiva’s oper-ations and investigations there.

Co-operation between Posiva andthe municipality of Eurajoki continuedalong the same lines as before.

Close co-operation with other Nor-dic organisations involved in nuclearwaste research continued both throughdirect contacts and within the frameworkof various joint groups.

The progress made in internationalresearch projects related to nuclear wastemanagement was monitored by partici-pating in conferences and joint projects.Close co-operation in the Äspö HardRock Laboratory project and in numer-ous EU research projects continued.

The progress of research pro-grammes in various countries was fol-lowed closely. Presentations were givenon Finland’s nuclear waste managementprogramme and research results in in-ternational conferences regarding nucle-ar waste. Participation in the OECD/NEA expert working groups involved,for example, discussion and assessmentconcerning site characterisation andsafety studies, and the decommissioningof power plants.

32

ALARA Engineering AB (Sweden)Astrock OyAustralian National University (Australia)Concave OyConrox Ab (Sweden)Consulting Engineers Paavo Ristola LtdCT Heikkinen OyEnprima Engineering OyEnterpris Limited (United Kingdom)Enviros Consulting Ltd (United Kingdom)Enviros Spain S.L. (Spain)EP-Logistics OyEvata Finland OyFacilia AB (Sweden)Finnish Consulting Engineers LtdFinnish Forest Research Institute

Parkano Research InstituteFinnish Geodetic InstituteFinnish Meteorological Institute

Meteorological ResearchFortum Nuclear Services OyGascoyne Geoprojects Inc. (Canada)GEA Consulting (Sweden)Geokeskus OyGeological Survey of Finland (GTK)

Espoo UnitGeoservice CentreKuopio Unit

Geopros OyGeosigma AB (Sweden)Gridpoint Finland OyHelsinki University of Technology

Laboratory of Materials TechnologyIntegrity Corrosion Consulting Ltd (Canada)JA Streamflow AB (Sweden)JP-Fintact OyJP-Suoraplan OyKalliosuunnittelu Oy Rockplan Ltd (KSOY)Karinta Consulting Ab (Sweden)Kivitieto Oy

Lapela OyLibenter OyMarintel KyMetso Paper, Inc.AB Nonlinear Solutions OyOutokumpu Technology OyOutokumpu Poricopper OyPRG-Tec OyRock Engineering Consultants (United Kingdom)Rollcon OySaanio & Riekkola Consulting EngineersSafety Assessment Management (SAM) Ltd

(United Kingdom)Safram OySerco Assurance (United Kingdom)Suomen Malmi OySuomen Paprico Oy/Viestintä-PapricoSuomen Teknohaus OySvensk Kärnbränslehantering AB (SKB) (Sweden)Swedish Corrosion Institute (Sweden)SwedPower AB (Sweden)Tampere University of Technology

Institute of Materials ScienceLaboratory of Engineering Geology

Technical Research Centre of Finland (VTT)VTT BiotechnologyVTT Building and TransportVTT Industrial SystemsVTT Processes

TVO Nuclear Services OyUniversity of Bern (Switzerland)University of Gothenburg (Sweden)University of Helsinki

Department of ChemistryDepartment of GeologyDepartment of Pharmacy

University of JyväskyläDepartment of Physics

Vibrometric Oy

CO-OPERATION PARTNERSList of research institutes, universities and consultants engaged

in nuclear waste management operations in 2003

33

QUALITY MANAGEMENT ANDENVIRONMENTAL MANAGEMENT

Posiva’s operations are aimed at the safeimplementation of nuclear waste man-agement in accordance with the needsof its owners and other clients, while pro-tecting the environment and fulfilling therequirements set by society. Posiva hasbeen upgrading quality ever since theCompany was established. The purposeof the quality system is to verify the sys-tematisation of Posiva’s operations.

In 2003, the upgrading of the oper-ating system continued in the directionof the ISO 9001 standard, also takingthe requirements of environmental stan-dard ISO 14001 into account. During2003, the Company also succeeded inoutlining the main and support process-es essential from the viewpoint of Posi-va’s operations.

The efficiency and reliability of thesystem in relation to the set targets wereassessed by Posiva’s internal audits. Theinternal audits were concerned with theconsideration of legislation, and safetyand environmental aspects in the opera-tions. The results of the audits broughtimportant subjects of development to

light to improve the efficiency of opera-tions.

The capability of some sub-suppli-ers to fulfil the technical, economic,quality and environmental requirementswas assessed during 2003. The operat-ing systems that are being applied andtheir development potential were sur-veyed. In addition, the functioning ofsome organisations was assessed bymeans of the audits of suppliers.

Instructions with a view to assuringthe quality of research, development anddesign work were specified. In assuringthe quality, Posiva also employed anoutside expert group to audit the materi-al produced by Posiva. The quality man-agement of the ONKALO project con-centrated on determining the processesand defining the quality requirements tobe established for the main contractor.

Induction training was given to newPosiva employees; they were also of-fered a five-day introductory course innuclear waste management to enhancetheir expertise. The entire personnel re-ceived training in quality issues in spring

2003. Annual development discussionscontinued as before.

The significance of corporate secu-rity will increase substantially when theconstruction of ONKALO begins. Withregard to occupational safety, the prin-cipal subjects of development in 2003included the implementation design ofrisk management and occupational safe-ty within the ONKALO project. In de-veloping the operating system, a deci-sion was taken to also consider the oc-cupational health and safety manage-ment system in accordance with OHSAS18001.

Fortum’s and TVO’s nuclear wastemanagement operations comply with thequality and environmental managementsystems applied in the companies’ nu-clear power operations. The businesssectors of Fortum Power and Heat havereceived various certifications (ISO14001 and ISO 9001). TVO’s environ-mental management system has beenawarded a certificate in accordance withthe ISO 14001 standard. TVO was ac-cepted into the EMAS register in 2001.

34

COSTS

RESEARCH

Research area Costs(EUR million)

Planning, co-ordination, information activities and general studies 0.5

Management of spent fuel and high-level waste 12.1

Management of intermediate-level and low-level waste 0.3

Decommissioning and decommissioning waste 0.2

Total 13.1

SUMMARY OF THE RESEARCH COSTS IN 2003

FINANCIAL PROVISION FOR NUCLEAR WASTE MANAGEMENT

The total cost of the nuclear waste man-agement research programme was someEUR 13.1 million. The cost estimates forthe research programme in 2003 were

about EUR 11.4 million. The researchprogramme was mostly implemented asplanned.

The above-mentioned costs do notinclude Posiva’s research assignmentssponsored by Tekes, the National Tech-nology Agency of Finland.

Funds for the future costs of nuclearwaste management are collected by theState Nuclear Waste Management Fund.The fund target is determined accord-ing to the liability of nuclear waste man-agement to be confirmed each year. Theliability comprises the future costs of themanagement of all wastes accumulated

by the end of the year in question.EUR 732.2 million was assessed as

the fund target for TVO in 2003, thecorresponding amount for Fortum be-ing EUR 545.1 million.

The Ministry of Trade and Industry(KTM) confirmed a liability amount ofEUR 763.8 million for TVO’s nuclear

waste management at the end of 2003and, based on this amount, a fund targetof EUR 763.8 million for 2004. ForFortum, KTM confirmed a liabilityamount of EUR 570.2 million and, ac-cordingly, a fund target of EUR 570.2million for 2004.

35

POSIVA 2003-01Vertical and Horizontal SeismicProfiling Investigations at Olkiluoto,2001Calin Cosma, Nicoleta Enescu,Erick Adam, Lucian BaluVibrometric OyMarch 2003ISBN 951-652-115-0

POSIVA 2003-02Baseline Conditions at OlkiluotoPosiva OySeptember 2003ISBN 951-652-116-9

POSIVA 2003-03ONKALO UndergroundCharacterisation and ResearchProgramme (UCRP)Posiva OySeptember 2003ISBN 951-652-117-7

POSIVA 2003-04Thermal Analyses of Spent NuclearFuel RepositoryKari IkonenVTT ProcessesJune 2003ISBN 951-652-118-5

POSIVA 2003-05Programme of Monitoring atOlkiluoto During Constructionand Operation of the ONKALOPosiva OyDecember 2003ISBN 951-652-119-3

POSIVA 2003-06Assessment of Disturbances Causedby Construction and Operation ofONKALOTimo Vieno, Jarmo Lehikoinen, JariLöfman, Henrik NordmanVTT ProcessesFerenc MészárosThe Relief LaboratoryOctober 2003ISBN 951-652-120-7

LIST OF REPORTS 2003

POSIVA 2003-07Hydrochemical Interpretation ofBaseline Groundwater Conditions atthe Olkiluoto site.Petteri Pitkänen, Ari Luukkonen,Sami PartamiesVTT Building and TransportMarch 2004ISBN 951-652-121-5

POSIVA 2003-08Air-oxidation Tests with Gd-dopedUO2 Preliminary DissolutionExperiments with pre-oxidized Gd-doped UO2+x

Kaija OllilaVTT ProcessesKristian LindqvistGeological Survey of FinlandOctober 2003ISBN 951-652-122-3

POSIVA 2003-09Narrow Gap Arc WeldingExperiments of Thick CopperSectionsRami Pohja, Heikki Vestman,Petra Jauhiainen, Hannu HänninenHelsinki University of TechnologyLaboratory of EngineeringMaterialsOctober 2003ISBN 951-652-123-1

POSIVA 2003-10Glacial Rebound and Crustal Stress inFinlandKurt Lambeck, Anthony PurcellResearch School of Earth Sciences,The Australian National UniversityNovember 2003ISBN 951-652-124-X

POSIVA 2003-11Thermal Analysis of KBS-3H TypeRepositoryKari IkonenVTT ProcessesNovember 2003ISBN 951-652-125-8

Fortum Power and Heat Oy,TJATE-G12-81Decommissioning of the Loviisa NPPIlpo Kallonen, Tapani Eurajoki andElias MayerFortum Nuclear Services LtdVantaa, December 2003ISSN 1457-3342 Summary ReportISBN 951-591-081-1

36

Teollisuuden Voima Oy

FI-27160 OLKILUOTO, Finland

Tel. +358 2 83 811

Fortum Power and Heat Oy

P.O.Box 100

FI-00048 FORTUM, Finland

Tel. +358 10 4511

Posiva Oy, FI-27160 OLKILUOTO, Finland

Tel. +358 2 83 7231, Fax +358 2 8372 3709

http://www.posiva.fi