Long-Term Interim Storage and Release of Radioactive Material - Dr. H. Behrndt

8/22/2019 Long-Term Interim Storage and Release of Radioactive Material - Dr. H. Behrndt

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InnenministeriumMecklenburg-Vorpommern

Long-term Interim Storage and Release ofRadioactive Material

Dr. W. Birkholz, Ministry of Interior of the Mecklenburg-Western Pomerania

Dr. H. Behrndt, TV NORD SysTec GmbH & Co. KG

E. Kaffka, Energiewerke Nord GmbH

R. Meister, Ministry of Interior of the Mecklenburg-WesternPomerania


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1. Introduction2. Licensing procedure and release measurements

3. The release procedure and campaigns

4. Mass flows of material from the Greifswald and Rheinsberg NPP and

third parties during release in Greifswald

5. Consequences of new release limit values: international and

Radiation Protection Ordinance (StrlSchV)

6. Summary and conclusions

Content


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1. Introduction

The disposal of material resulting from the dismantling of a nuclearfacility is an important logistic task which is time-determining for the

dismantling procedure.


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The Greifswald NPP in 1995

1. Introduction


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Expected mass of radioactive material during the dismantling of the GreifswaldNPP (scheduled in 1995)

residues to b e released

500.000 Mg

waste

100.000 Mg

without any restriction

1.200.000 Mg

1. Introduction


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2. Licensing procedure and release measurements

Reunification of Germany - shut down of the 5 units of the GreifswaldNPP in 1990

Unification treaty operating licenses for nuclear power plants of theformer GDR were only valid until 30 J une 1995

Decommissioning license - issued by the Ministry of the Interior ofMecklenburg-Western Pomerania on 30 J une 1995

Decommissioning license - defined the regular bases fordisposal and free release measurement


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Decommissioning and dismantling strategy (1995)

Main features of the primary dismantling concept:


dismantling and on-site cutting of components just as far as necessaryto remove them from the facility,

establishment of separate storage, cutting, and free release measurementfacilities,

classification of plant parts according to activity level and determination of fewcovering nuclide vectors

decay storage (approx. 15 years) of plant parts and components for a

simplification (under radiological aspects) of later cutting

remote cutting of reactor pressure vessels (units 1 to 4, Rheinsberg NPP) andinternals


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Remote cutting of reactor internalsInterim storage of

dewateredwaste baskets



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The modified concept:

Remote cutting of reactors from units 1 to 4 and of reactor internalsfrom units 3 and 4 is not scheduled anymore.

Long-term decay storage of 50 to 100 years will follow.

Changing of the decommissioning and dismantling strategy

(license of August 2007)



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Decay storage of large components for cutting under radiologically morefavourable conditions (target value Co-60 activity < 30 Bq/g)

Original data state2004

Decay period for targetvalue

Bottom plate of corebasket of unit 1

- Co-60 4,6E+14 Bq - spec. Co-60109,1 a

Reactor pressurevessel of unit 1

- Co-60 1,5E+12 Bq - spec. Co-6055,9 a

Bottom plate

protecting tubesystem of unit 1

- Co-60 3,4E+14 Bq -spec. Co-60

106,4a



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Removing a reactor pressure vessel



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Removing a steam generator



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Transport of a reactor pressure vessel into the Interim Storage North



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Interim Storage North - Storage of large components



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Free release limit values and release procedures were regulated by the

decommissioning license from 1995.

Reasons to use the free release limit values and release procedures of 29of the Radiation Protection Ordinance:

EWN replaced the free release limit values from 1995 by theregulations of 29 of the Radiation Protection Ordinance.

opening of a final storage not till 2013

a modified dismantling strategy

the license to treat and free release residues from other nuclearfacilities


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Radiological categorization

Category 1 Release without any restrict ionsno contamination - due to operation history contamination is

not possiblerandom check measurements - supervised by an expertfrom supervisory authority

Classification according to technological aspects and operation history

Category 2 - Suspected materialcontamination possible - due to technological procedures

and in comparison with similar

facility areas contamination issuspected

Category 3 - Contaminatedcontact with radioactive material



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Release procedure

A release measurement campaign comprises a certain dismantlingproject


total mass, number of chargesorigin of the material

radiological category, nuclide vectorresults of the preliminary inspectionsmethod for measuring

A release measurement campaign is separated in charges.For every kind of material exists a separate charge.

Application for a release measurement campaign includes


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Kinds of material for release

CST Carbon steel

AUS Austenite

NEM Non-ferrous metal

ELT Electrical parts

ELM Electric motorsKAB Cable, with and without insulation

BET Concrete / concrete rubble, concrete parts and building structures

SON Other (e.g. industrial safety means, waste that cannot be sorted,sweepings, rubble remains, glass and ceramics, detergents)

ISW Insulation wool



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Release procedure

A release measurement campaign comprises a certain dismantlingproject


total mass, number of chargesorigin of the material

radiological category, nuclide vectorresults of the preliminary inspectionsmethod for measuring

A release measurement campaign is separated in charges.For every kind of material exists a separate charge.

Based on the inspection report of its expertthe supervisory authority releases free measured charge parts.

Application for a release measurement campaign includes


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Disposal paths

A Unrestricted release (according to 29 clause 2.1)

B Restricted Release (according to 29 clause 2.2)

C Release under special conditions l icenced byauthority (according to 29 clause 4)

D Decay storage



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Hall with release measurements facilit ies



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Residues released and disposed of (1995 2009)

KGR KKR Third parties

Dumpsite 25 582 Mg 280 Mg 7 Mg

Scrap dealer 32 198 Mg 596 Mg 181 Mg

Reuse of concrete 109 442 Mg

Combustion 508 Mg 3 Mg

Other use 3 805 Mg 1 Mg

Buildings for reuse 5 684 Mg

Total: 177 219 Mg 876 Mg 192 Mg

4. Mass flows of material


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Decay storage

Objectives to be achieved by decay storage:1. Free release of a bigger amount of material

2. Cutting of components under radiologically more favourable conditions

3. To decrease the expenses for final storage


Consequences: Recirculation of resources into the cycle of material after

release measurement

Minimization of radioactive waste Avoiding remote dismantling Minimization of costs for final storage (containers, transport,

volume)

4 Mass flows of material


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Sorting of condit ioned waste for the final storage ERAM

Conditioned waste

(690 Mg)

Free releasemeasurement(270 Mg)

Decay storage

(150 Mg)

Radioactive waste(270 Mg)



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25Folie: 25

Expected mass of radioactive material during the dismantling of the GreifswaldNPP (planned in 2008)

residues to be released

549.000 Mgwaste

16.000 Mg

without any restriction

1.235.000 Mg



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5. Consequences of new release limit values

Time course example of one nuclide vector

0

10

20

30

40

50

60

70

80

J ul

95

J ul

96

J ul

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J ul

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J ul

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J ul

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J ul

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J ul

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J ul

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J ul

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Period

Percentage

ofthe

nuclides

Co-60

Ni-63

Fe-55

Cs-137


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Comparison of current exemption quantities and release limit valueswith the scheduled IAEA values, data in Bq/g

Co-60 Fe-55 Ni-63 Cs-137 Am-241

Exemptionquantities 10 10.000 100.000 10 1

Release formelting 0,6 10.000 10.000 0,6 0,3

Unrestrictedrelease 0,1 200 300 0,5 0,05

IAEA: RS-G-1.7 0,1 1000 100 0,1 0,1

5. Consequences of new release limit values


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- Removed material

Category 1 86.000 Mg

Category 2, 3 180.000 Mg

- five covering nuclide vectors for release measurements

- separation of dismantling and conditioning/releasein different facilities

- building of an interim storage


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Strategy of long-term decay storage of large components leads to

- reduction of the dismantling time

- reductionof the personnel's exposure to radiation- a considerable decrease of the volume of the radioactive waste

supposed to be stored in a final storage

(100.000 Mg planed in 1995 20.000 Mg planed in2008)

- to significant cost savings

Prerequisite for this saving

- a final storage thatwill be open long enough

- the adherence to the currentrelease limit values


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Greifswald NPP in 2009


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Thank you for

your attention!

Documents

Long-Term Interim Storage and Release of Radioactive Material - Dr. H. Behrndt