Decommissioning (technical knowledge/experience; national ... · Michele Laraia, IAEA World Nuclear...

International Atomic Energy Agency

Decommissioning (technical knowledge/experience;

national strategies / policies; main issues; future trends)

Michele Laraia, IAEAWorld Nuclear University- Summer Institute 2008

Ottawa, Canada, 18 July 2008


ContentsContents

• Decommissioning: the global overview (number of facilities, policies and strategies, trends)

• Planning issues• Organization and management issues• Technological issues• Safety issues• Integration of decommissioning constraints into new

projects• Case study No.1 : The preliminary decommissioning

plan; how good is good enough?• Case study No. 2: Identifying decommissioning

stakeholders


Decommissioning Decommissioning –– a safetya safety--oriented IAEA oriented IAEA definitiondefinition

The administrative and technical actions taken to allow the removal of some or all of the regulatory controlsfrom a nuclear facility (except for a repository or for certain nuclear facilities used for the disposal of residues from the mining and processing of radioactive material, which are ‘closed’ and not ‘decommissioned’).


Decommissioning (IAEA Safeguards Decommissioning (IAEA Safeguards Glossary, 2001)Glossary, 2001)

• Decommissioned facility is “an installation or location at which residual structures and equipment essential for its use have been removed or rendered inoperable so that it is not used to store and can no longer be used to handle, process or utilize nuclear material”

• See Tajikistan reactor never operated but still subject to safeguards provisions


A broader vision of decommissioningA broader vision of decommissioning

• The two main objectives of decommissioning are to render the site permanently safe and to recover it, as far as practicable, for reuse (TRS # 444, WNA 2006)


A frequent confusionA frequent confusion

• Decommissioning addresses to the chemical, physical and mechanical processes in removing structures and components of a nuclear facility

• Environmental remediation addresses the cleanup and recovery to other uses of radioactively contaminated land and waters (restoration aims at reaching pristine conditions) . Removal is often out of question (e.g. million tons of uranium mill tailings)

• The technical literature is often ambiguous on these terms• Site remediation may include elements of decommissioning (the

buildings) and the environment• This lecture mostly addresses decommissioning, not ER.


Status of the Decommissioning of Nuclear Status of the Decommissioning of Nuclear Facilities around the World*Facilities around the World*

• Nuclear Power Plants• Operating: 446• Under construction: 45• Shutdown, under decommissioning: 107• Decommissioned: 14

• Research reactors and critical assemblies• Operating: 288• Under construction: 9• Shutdown, under decommissioning: 119• Decommissioned: 404

* various IAEA sources, 2004-2005


Status of the Decommissioning of Nuclear Status of the Decommissioning of Nuclear Facilities around the World*Facilities around the World*

• Fuel cycle facilities (uranium milling, uranium conversion/recovery, uranium enrichment, fuel fabrication/heavy water production, fuel reprocessing)• Operating: 423• Under construction: 19• Shutdown, under decommissioning: 297• Decommissioned: 192

• Medical, research and industrial facilities: ~ 320 000

• Cold war legacy

• Total decommissioning liability for the period up to 2050 of about $ 1000 billion ($ 1 trillion) !!! Note these were 2005 $, not today’s !!!

*various IAEA sources 2004-2005


Status of the Decommissioning of Nuclear Facilities around the WStatus of the Decommissioning of Nuclear Facilities around the World*orld*

• Not to mention NORM*- contaminated facilities and sites

• Even approx numbers for NORM facilities are hard to estimate, since they depend on regulations still in evolution

*Naturally Occurring Radioactive Material


Reasons for DecommissioningReasons for Decommissioning

• Uneconomical Operation• Technical Obsolescence• Conclusion of Research Program• Safety Considerations• Change in Governmental Policy• Others - Accident, etc.


DecommissioningDecommissioning--related activities during related activities during the lifecycle of a nuclear facilitythe lifecycle of a nuclear facility

State

Design,

Construction &

Start-up Phase

Operating

Phase

Shutdown

Pre-

decommissioning

Phase

Safe Enclosure

Preparation

Safe Enclosure

Period

Final

Decommissionin

g

Phase

Activities

Initial

Decommissioning

Plan

Ongoing

Decommissioning

Plan

Final

Decommissioning

Plan

Source Term

Removal/

Defuelling.

Waste

Conditioning

Site Preparation

Initial

Dismantling

Surveillance &

Maintenance

Final

Dismantling.

Final Survey &

License

termination


Decommissioning StrategiesDecommissioning Strategies

• Ideally planning for decommissioning should be started at the facility design stage and notafter the facility has been permanently shutdown

• Cost/benefit evaluation should be used to determine the best strategy

• The sooner the better: early planning will allow timely allocation of funding and infrastructure


After final shutdown, in a lack of plans for After final shutdown, in a lack of plans for decommissioning…decommissioning…


Decommissioning Strategies (Decommissioning Strategies (ctdctd))

• Former IAEA decommissioning strategies• Stage 1 - Preservation• Stage 2 - Partial Dismantling• Stage 3 - Full Dismantling

• USA decommissioning strategies• DECON - Immediate Dismantling• SAFSTOR - Safe Enclosure & Deferred

Dismantling• ENTOMB - In-Situ Disposal



• Decommissioning starts with the implementation of the decommissioning strategy and ends with the release of the site – typically strategies are *:• immediate dismantling• deferred dismantling (Safe Enclosure)• entombment

* As defined in IAEA literature


Decommissioning Strategies (Decommissioning Strategies (ctdctd))• Variants on Deferred Dismantlement

• Safe enclosure duration• Short <15 years• Medium 15 - 40 years• Long >40 years

• Active and passive variants of safe enclosure• A number of factors influence the approach • Combinations of different features of each option• Can opt out of Safe Enclosure at a future point in

time



• An emerging decommissioning strategy: “continuous” decommissioning

• Start immediately, continue for a relatively long time depending on availability of resources

• Example: Rancho Seco NPP, USA


Factors Impacting Selection of a StrategyFactors Impacting Selection of a Strategy• Legislative and regulatory requirements• Spent fuel management strategy• Waste arising and national waste

management strategy• Finances • Condition of the facility – radiologically and

structurally• Planned future use of the site• Availability of technology• Retention of operating staff and records


Factors Impacting Selection of a Strategy Factors Impacting Selection of a Strategy ((ctdctd))

• Societal considerations -environment, employment and public perception

• Interactions with other countries national nuclear programs

• Experience and expertise to manage complex projects


Financial FactorsFinancial Factors

• Now many countries have some form of funding mechanism in place

• Private versus State owned facilities can impact timing

• Premature shutdown for NPP is still an open issue and limits options if it occurs

• Long term assurances of fundingavailability (see 135-yr deferred dismantling strategy in the UK)


Radiological FactorsRadiological Factors

• Dose rate level reductions taper off after 40-50 years for most reactors (Co-60 controlling decay)

• Some longer-lived isotope issues may still present themselves (Cs-137, Sr-90)

• Lower worker occupational exposures in in research reactors make deferred dismantling really not very practical

• Remote operations may be used to reduce doses in immediate dismantling cases

• Prevailing α emitters –e.g. at nuclear fuel cycle plants- render deferral useless or counter-productive ( Pu to Am decay)


Waste Management FactorsWaste Management Factors• Lack of waste disposal sites / inability to site new

facilities. Escalating disposal costs

• Spent fuel management issues

• Deferral strategies may allow lowering of waste disposal categorization for some waste streamsHLW >>>LLW, LLW >>>exempt

• Large decommissioning waste volumes may tax the disposal site ability to handle

• Waste storage can be an acceptable alternative to disposal (e.g. at Greifswald NPP, Germany)

• Ongoing search for new, additional waste management resources ( e.g. VLLW, conditional disposal, smelting and recycle –see new Studsvikplant in UK etc)


Land Use FactorsLand Use Factors

• Many successes in reuse of both research reactor and NPP sites – USA

• Land costs are at a premium in some countries – Japan prescribes immediate dismantling by law

• Bound to become even more of an issue with stakeholders and involve them more in future decision making. Generally, stakeholders favor early dismantling and site reuse


CONSTRUCTION

OPERATION

DECOMMISSIONING

SITING

AND NOW ?

REDEVELOPMENT!

CLOSING THE NUCLEAR LOOP


“Vaporsphere” at Argonne

National Laboratory, USA: from

nuclear facility to warehouse

“Vaporsphere” at Argonne

National Laboratory, USA: from

nuclear facility to warehouse



Fort St Fort St VrainVrain, USA: from nuclear power , USA: from nuclear power plant to gas plant to gas –– fired power plantfired power plant


The ORNL Graphite Reactor MuseumThe ORNL Graphite Reactor Museum


Specific StrategiesSpecific Strategies• Factors favoring Immediate Dismantlement

• Decommissioning funds are available and costs are known

• Low-level waste disposal sites are available• Experience of facility personnel and proven technologies

are available• Minimizes future regulatory uncertainty• Minimizes near-term impact to the local economy• Presents positive public perception• Eliminates corporate liability sooner and makes site

available for re-use• Allows for earlier license termination• Examples of fully dismantled NPPs (Maine Yankee, Big

Rock Point, Trojan etc USA; Niederaichbach, Germany; JPDR, Japan)


Completed projects: Maine Yankee , USACompleted projects: Maine Yankee , USA


Specific Strategies (Specific Strategies (ctdctd))• Factors favoring Deferred Dismantlement

• Funds not available for immediate dismantlement

• Smaller radioactive waste volumes• Lower staff radiation exposures• More time to resolve waste management issues

(e.g. graphite at Vandellos NPP)• Avoid industry “learning curve”• Some areas may be able to be immediately

reused• Benefit from technology enhancements• Multi-unit sites• Examples of NPPs in Safe Enclosure:

(Barsebaeck, Sweden; Humboldt Bay, USA; all Magnoxes, UK; Vandellos, Spain).


VandellosSafestore:

former workshops at

the base of the reactor are

being used for the Mestral

Technological Centre

VandellosSafestore:

former workshops at

the base of the reactor are

being used for the Mestral

Technological Centre


Specific Strategies (Specific Strategies (ctdctd))• Factors favoring Entombment

• Used only in rare instances • Geographic location – remote sites• Governmental controls – may be practical• Limited funding and resources available –

quick and easy solution• Examples: earlier US reactors, Georgia IRT

• However• Waste disposal site created • Creates longer term liability / monitoring

requirement• Presents burden to future generation


Georgia reactor: before and after Georgia reactor: before and after entombmententombment


Specific arguments for Greifswald to go to immediatedismantling

Need to re-employ exceedingly large operational staff(thousands of workers) in an economically depressedregion.Prompt decision on decommissioning strategy allowing re-employment of key staff.Availability of waste disposal facility at the beginning ofthe decommissioning project.Funds made available by State.Full set of clearance criteria harmonized to internationalstandards.Difficulty of installing safe storage for WWERs (nosecondary containment).


Multiple Plant SitesMultiple Plant Sites• Multiple plant sites will typically wait until

all the facilities are ready for decommissioning to gain an “efficiencies of scale” before decommissioning any one unit• Examples fr USA– Dresden 1, Peach

Bottom 1, Indian Point 1, Millstone 1

• In some cases there may be co-located on a common site old retired units in Safe Storage awaiting dismantling and new operating units of a next generation design


Strategy TrendsStrategy Trends• Technologies are generally readily available for

immediate dismantling

• Trends are based on country specific drivers – ex. waste disposal site availability at reasonable cost

• Major obstacles:• Lack of funding• Lack of waste management & disposal facilities

(e.g. UK)

• Life extension practices for NPP; fewer decommissioning projects in the near future


Trend: regardless of a preference for immediate Trend: regardless of a preference for immediate dismantling ( dismantling ( IAEA’sIAEA’s preferred strategy), still some 50% of preferred strategy), still some 50% of

recently shutdown recently shutdown NPPsNPPs opt for delayed dismantlingopt for delayed dismantling

EVOLUTION OF NPP DECOMMISSIONING STRATEGY

52 2 2 2

12

9

2 34

14

2

3

3

1

1

8

2

6 13

2

3

7

5

1

2

32

3

0

5

10

15

20

25

30

35

1980 andbefore

1981-1985

1986-1990

1991-1995

1996-2000

2001-2006

Shutdown date

N° o

f NPP

Uni

ts

Entombment

Strategy under consideration

Strategy changed from safe enclosure todismantlingSafe enclosure pursued

Safe enclosure achieved

Dismantling underway

Dismantling completed


Current issues and challenges for the Current issues and challenges for the future* future* -- Planning for DecommissioningPlanning for Decommissioning

Decommissioning policies, strategies and plansLack of clarity in energy and decommissioning policiesMissing decommissioning strategies for multi-facilities sitesPeer review of decommissioning policies, strategies and plans

Planning the transition from operation to decommissioning.

Lack of regulation to carry out the transitionRestructuring the organization (e.g. privatization, funding issues)Preservation of knowledge and competence

* Issues in red arbitrarily selected for discussion.


Current issues and challenges for the future Current issues and challenges for the future --Planning for Decommissioning (cont’d)Planning for Decommissioning (cont’d)

• Documentation• Lack of guidance on initial/ ongoing decommissioning plans.• Harmonization of national legislation with EU directives and IAEA (e.g.

EIA standards).• Funding• Insufficient funding can cause decommissioning delays. Deferral by

default.• Accurate cost estimates should be performed (e.g. using the

EC/IAEA/NEA guidelines). More harmonization needed.• Funding mechanisms should be periodically reviewed.• Funding mechanisms should not hinder fair competition (EU concerns).

Internal funds? Segregated funds? To what extent can these funds be used before decommissioning?


The The CintichemCintichem case: from 25 M$ to 100 M$. Characterize ! case: from 25 M$ to 100 M$. Characterize ! Characterize ! Characterize ! Do not miss leakage Characterize ! Characterize ! Do not miss leakage

migrating from plant basement, to foundation, to bedrock, migrating from plant basement, to foundation, to bedrock, to groundwater…Later can be too late.to groundwater…Later can be too late.


Current issues and challenges for the Current issues and challenges for the future future -- Decommissioning OrganizationDecommissioning Organization

• Cultural change from operation to decommissioning• Operators motivation and mentality (e.g. a research reactor staff).• Sequence of one-off operations in a changing environment instead of

routine.• Loss of knowledge.• Training and providing necessary information.• Leadership and adaptation of procedures.• Improve the record keeping.• Social issues• Loss of jobs.• Early planning of alternative employment incl. site reuse.• Early identification and involvement of the stakeholders


Current issues and challenges for the future Current issues and challenges for the future --Decommissioning Organization (Decommissioning Organization (cnt’dcnt’d))

• Organization structure• Change of responsibilities.• Interactions operator – contractors – regulators.• Promotion of international exchange of expertise and lessons learned.• Clearly define objectives, functions and responsibilities• Early planning of interactions, regular exchange of information.• Transparency.• Project Management• Lack of experience with operators and regulators.• Difficulty to estimate contingencies.• Control of compliance with plans and schedules.• Learning by doing, dissemination of experience, focus on key issues.• Adopting cost estimating, risk and contingency management

techniques.• Regular monitoring and follow up of the plans and schedules.


Post operation Preparation of Safe

EnclosureWaiting Period Dismantling

26/3/1997 1/3/2001 31/12/2003 2043

4 years 3 years 40 years 4 years

Fig.1 Decommissioning Phases Dodewaard

Final shutdown


Director

Head of NPP

Support Security

Quality Assurance

Operations Maintenance Technical Support

Fig. 2 Dodewaard: organization during normal operation


Director

Head of NPP

AssistantHead NPP Security

Quality Assurance Communication

Operations and Maintenance

Decommissioning Personnel and Support

Fig. 3 Dodewaard: organization during post-operational phase


Director

Head of NPP

AssistantHead NPP Security

Quality Assurance Communication

Decommissioning Personnel and Support

Fig. 4 Dodewaard: organization during preparation for safe enclosure


Current issues and challenges for the Current issues and challenges for the future future -- Decommissioning technologiesDecommissioning technologies

• Decontamination• If, when, how and what to decontaminate.• Effluent treatment (e.g. decontamination solutions).• Cost - benefit analysis before any decision.• Decontamination is not cure-all.• Dismantling• Sequence and timing of dismantling.• Logistics.• Maintenance experience for large equipment, similar

decommissioning projects, early planning.


Current issues and challenges for the future Current issues and challenges for the future --Decommissioning technologies (Decommissioning technologies (cnt’dcnt’d))

• Waste and material management• Secondary waste management.• Categorization and segregation of material.• Management of special and toxic materials (e.g. graphite, Be, Na, crystallized

boric acids, asbestos).• Comprehensive information on different technologies and drawbacks.• Training of staff, proper technology and criteria to help sorting and treat

different waste streams.• R&D programs, IAEA to promote international solutions for special

waste management.• Criteria for selection of technology• Not sufficient clarity of the criteria for selection of decommissioning

technology.• Cost – benefit analysis (e.g. economics), characterize only as needed,

waste acceptance criteria, etc.• Characterization in mixed α – β – γ fields• Characterization at close-to-clearance levels


Current issues and challenges for the Current issues and challenges for the future future -- Decommissioning SafetyDecommissioning Safety

• Safety case

• Definition of a set of licensing documents required for D&D.

• Evolution of safety issues during the decommissioning process and their associated documents.

• Lack of experience in developing safety assessments.• Optimize and give flexibility to the licensing process.• Reflect the changes in the decommissioning process.• Training and dissemination of experience (e.g. safety

assessment).• Preliminary vs. final decommissioning plans.


Current issues and challenges for the Current issues and challenges for the future future -- Decommissioning Safety (Decommissioning Safety (cnt’dcnt’d))

• Radiological vs. non radiological risks• Possible lack of communication between different

regulatory bodies. Establish legislation and early dialog between the different regulatory bodies.

• How to balance radiological and non radiological hazards.

• Develop adequate methodology to take into account bothtypes of hazards.

• Definition of responsibilities.


Some good examples of bad practices…Some good examples of bad practices…


Current issues and challenges for the Current issues and challenges for the future future -- Decommissioning Safety (Decommissioning Safety (cnt’dcnt’d))

• Clearance and site release criteria• Introduction of harmonized clearance levels.• Use of RS-G-1.7, as a basis for improving

harmonization.• Consider adoption of conditional release criteria for

materials and sites• Economics/practicability of current release criteria.

• D&D with limited resources• Develop graded approach methodologies focusing on

the most relevant safety related issues.• Minimize decommissioning costs when having limited

resources


Integration of decommissioning Integration of decommissioning constraints into new projectsconstraints into new projects

• Lessons learned from complete decommissioning projects

• Decommissioning practitioners to talk to designers• Be realistic: a plant is not designed to be

decommissioned• The time factor: design is followed by 40- 60 year

operation and perhaps as many years of safe enclosure


INFORMATION SOURCES (CTD)INFORMATION SOURCES (CTD)

• Experienced technical and management staff members that have performed decommissioning of nuclear facilities – regulators, operators and contractors

• Often lessons learned are detailed in project final reports and in some instances specific reports on lessons learned

• Site visits to units or facilities in decommissioning is another useful way to learn what others have done in similar situations

• Do not trust vendors blindly


INFORMATION SOURCES (CTD)INFORMATION SOURCES (CTD)

• Dedicate resources to track projects as they are happening

• In addition, there are some sources of lessons learned available on the Internet (e.g. the DOE programme)


A BASIC PROBLEM IN TRANSFERRING A BASIC PROBLEM IN TRANSFERRING DECOMMISSIONING LESSONS LEARNED TO DECOMMISSIONING LESSONS LEARNED TO

DESIGNERS AND BUILDERS OF NEW FACILITIESDESIGNERS AND BUILDERS OF NEW FACILITIES

• Decommissioners and designers/builders belong to different categories, well distinct in space, time, organizations, professional / contractual interests and motivations

• A conscious effort is needed by an independent / overarching authority to establish and enforce the link


A FEW SELECTED CRITERIA TO REVIEW A FEW SELECTED CRITERIA TO REVIEW DESIGN/CONSTRUCTION IN THE LIGHT OF DESIGN/CONSTRUCTION IN THE LIGHT OF

DECOMMISSIONINGDECOMMISSIONING• Decide on scope of decommissioning e.g. what is

going to be left behind following decommissioning (foundations, discharge pipes, etc.)

• Avoid considering unproven decommissioning technologies – let someone else test or evaluate and ready the new technology. Keep it simple ! Do not re-invent the wheel !

• Maintain a strong document control system including effective retrieval and prompt disposition of unneeded records. “Flag “ decommissioning-related records !



DECOMMISSIONING (CTD)DECOMMISSIONING (CTD)• ‘As built’ drawings are often not accurately ‘as built’

and other documentation may be lacking

• Time is money – tackle a problem with the biggest equipment space constraints allow to be used

• Facility maintenance is a critical activity also for eventual decommissioning. What is good for maintenance and repair is also good for D&D

• Do not overlook the issues of:• Groundwater contamination• Soil contamination• Know what is underground• Hence: waterproof coatings on floors and walls



DECOMMISSIONING (CTD)DECOMMISSIONING (CTD)• Evaluate options for large intact component removal

versus size reducing larger items

• Understand the packaging and disposal requirements even at the design stage

• Make provisions to maintain detailed and accurate records on the contents of your waste packages


Decommissioning wasteDecommissioning waste

• Large items

FrancePWR Vessel Head, lAube, France

US Ecology, Richland



DECOMMISSIONING (CTD)DECOMMISSIONING (CTD)• Closely evaluate (cost/benefit analysis) any and all

opportunities to decontaminate material for release or to recycle/reuse decommissioning projects

• Be ready to face changes of:the reference decommissioning strategy;the future destination of the site.

• Be ready to face the evolution of:the legal framework;the financing of the decommissioning project;the waste fees.


Case Study No. 1: the preliminary Case Study No. 1: the preliminary decommissioning plan (PDP) : how good is good decommissioning plan (PDP) : how good is good

enough?enough?• The PDP is to prove that end-of-life decommissioning

can be done in a safe, cost-effective and timely manner• The PDP should be in place at the design and

construction stage• The PDP should be a living document: it should evolve

in detail until the final, ready-for-action plan is implemented

• Prime goal of the PDP: collecting decommissioning funds during operation, hence funding mechanisms to be described in the PDP

• What more contents? How should the PDP evolve? Who should be in charge? What may change the assumptions of the PDP?


Case study No. 2: Identifying decommissioning Case study No. 2: Identifying decommissioning stakeholdersstakeholders

• A stakeholder is a person or entity that affects / is affected by decommissioning

• Traditional stakeholders: operator & regulator• D&D stakeholders: contractors, funding

bodies, Ministries and other policy-makers• Other stakeholders: local communities, trade

unions, shareholders• More stakeholders?• How to involve stakeholders?


Website on IAEA activities http://goto.iaea.org/decommissioning/

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