TRENDS IN DISPOSAL AND DISPOSAL DESIGN CONCEPTS

FOR LLW

By:

Alan CarolissenSenior Manager: Nuclear Liabilities Management

SAFETY PRINCIPLES AND REQUIREMENTS

HLW ILW LLW VLLW VSLW

WASTE TYPES AND DISPOSAL OPTIONS

REGULATORY ASPECTSTECHNOLOGY OPTIONS

ECONOMICSSOCIETAL ISSUES

MANAGEMENT OPTIONS – TREATMENT & DISPOSAL

TRENDS IN DISPOSAL

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PROLONGED STORAGE

• Storage = “Holding of SNF or RW in a facility that provides for its containment, with the intention of retrieval” (article 2 of the IAEA Joint Convention)

• Prolonged => Longer than ‘usual’ design life, but not unlimited ~ 100 years

But:• A next step required• Transferring

responsibilityto futuregeneration

HABOG, The Netherlands

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PROLONGED STORAGE - REASONS• Waiting for public acceptance• Waiting for know-how• Wait & see

option• No repository available

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MULTINATIONAL SOLUTIONS+ Economically effective+ Increased security+ Scenarios known? Legal matters? Financial aspects ? Long-term liabilities? Ownership of RW? Public acceptance

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UPGRADING FACILITIESInitiating events:• Regulatory changes

or non-compliance• Releases/exposures

exceeding limits• Stakeholder concerns

DISPOSAL CONCEPTS

Various Disposal Concepts

• Simple near-surface facilities (18%)• Engineered near-surface disposal facilities (62%)• Mined cavities (7%)• Geological repositories (4%)• Other (9%)

Simple near-surface facilities• Examples: Vaalputs – South Africa

Barnwell – USA

• Both benefit from the low permeable clay layers and/or low precipitation rate at site.

• The disposal system consists of trenches with a slightly sloped floor covered with a layer of sand to facilitate collection of infiltration water in a trench drain which is monitored.

Main features of trench• Shallow trench about ± 5m deep

• Construction cost low

• Multiple engineered barriers to act as lining to retard migration of problematic waste (Multi-layer cover system)

• Engineered containers

• Backfill to act as chemical barrier

• Be able to accommodate small waste consignments

Existing Disposal Concepts at Vaalputs

Low Level Waste

Intermediate Level Waste

Engineered near-surface disposal facilities (Vaults)

• Examples: Drigg – UK (Simple trench concept was phased out)

la Manche – FranceEl Cabriel – SpainRokkasho – JapanMochovce - Slovakia

• The disposal system consists of vaults, set on or below ground level, consist of a concrete base and walls with an underlying drainage layer. Any drainage from within or below the vault can be monitored.

Main features of the vault

• Concrete vault constructed on or below the surface• Multiple engineered barriers to act as lining to retard

migration of problematic waste • Engineered containers• Retrievability if required• Construction cots high comparing to trenches

Below-ground vault

Above-ground vault

Slovak facility at Mochovce

Vault type repository

Japanese facility at Rokkasho

Vault type repository

ground surface

cover soil

bentonite/sand mixture

concrete pit

waste

porous concrete layer

drain pipecement base backfill

inspectiontunnel

bedrock

bedrock

Spanish facility at El Cabril

Vault type repository

El CabrilSpain

British Facility at Drigg

Trench and Vault type repository

Mined cavities• Examples: Czech Republic

SwedenFinlandNorway

• The disposal system consists of chambers constructed 60 to 100 meters underground

SFR

Sweden Facility at Forsmark

SFR facility for LILW: caverns and silos at c.50 m depth in granite: Forsmark Sweden (SKB)

L ≈ 160 mW ≈ 19.5 mH ≈ 16.5 m

Vtot ≈ 47,650 m3

Vstorage ≈ 13,090 m3

Capacity ≈ 7,500 Concrete- or steel moulds

1BMA - Rock vault for ILW

2011-10-

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IAEA Disponet work shop

BMA – Intermediate level waste

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Rock cavityØ ≈ 31 mH ≈ 70 m

Concrete cylinderØ ≈ 27.5 mH ≈ 53 m

Vstorage ≈ 17,740 m3

Capacity ≈ 10,000 concrete moulds

Silo for ILW

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SiloThe shafts in the core of the silo contains bitumen

Top of the Silo

2011-10-

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IAEA Disponet work shop

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Geological repositories• Examples: Morsleben & Konrad – Germany

Nirex – UK

• The disposal system consists of tunnels constructed 400 to 800 meters underground(old mines no longer in use)

Konrad, Germany

Images: BfS, Germany

Shaft 2 today

Shaft 2 in 2014

LILW disposal vaults at c.850 m depth

Other• Examples: Borehole disposal – Russia, USA

• The disposal system consists of boreholes bored to a depth of between 5 to 50 meters

Main features of borehole• Big diameter borehole between 4 and 30 meters

deep• Small volumes of waste• Concrete casing• Grouting designed to retard migration of

problematic radionuclide at each level after emplacement

• Engineered container• Multi-layer cover system

Borehole

3m

2m

15m

Borehole

2m

2m

Lessons learned from Existing disposal facilities

• Put waste in a structurally stable form, arrange waste carefully in the disposal facility, and fill spaces between containers to avoid settling

Bathtub effect

Lessons learned from Existing disposal facilities (Cont.)

• Design and operating procedures are important to facility performance

• Do a complete geologic, soil, and water analysis to determine the site characteristics before constructing a facility

• Do not put liquid waste into the disposal facility (corrosive & increase migration)

• Detection and Monitoring systems imperative• A strong quality assurance program, employee training, and

regulatory oversight• Audits and regular inspections help to ensure that the waste reaching

the disposal site has acceptable content and form.

Design Trends

• Use of multiple engineered barriers

• Move towards Vault type repository

• Need for repositories that can take small quantities of waste

Thank you for your attention