GerhardProehl

Safety Standards
for theManagement ofRadioactive Waste

IAEA: International Atomic Energy Agency
Founded in 1957 by the United Nations
Article III, Functions
Paragraph A.6.
“ To establish or adopt, in consultation and, whereappropriate, in collaboration with the competent organs of
the United Nations and with the specialized agencies
concerned,

standards of safety for protection of health andminimization of danger to life and property (including suchstandards for labour conditions), andto provide for the application of these standards toits own operation as well as to the operations making useof materials, services, equipment, facilities, andinformation made available by the Agency …; “Statute 1957

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IAEA Safety Standards Categories
Fundamental Safety Principles

Requirements: What to do?

Safety Fundamentals
Safety Requirements

Safety Guides

Best Practice to meet
Requirements: How to do?

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IAEA Safety
requirements
and standards

Safety Standards on Safety Assessment

5Radioactive Waste Management
All administrative and operational
activities involved in• Handling• Pre-treatment• Treatment• Conditioning• Transport• Storage and• Disposal of radioactive waste.

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! Storage is only a temporary solution• Storage is not sustainable in the long term

− Requires active controls for safety and security− On-going responsibilities and costs (e.g. for maintenance, refurbishment,monitoring, security)• Events and developments with impact on the safety of storage− Human-induced• Wars and terrorism• Urban growth• …

− Natural:• Storms and floods• Earthquakes• Volcanic eruptions• …
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• Overview of geological disposal andits implementation• Legal and organizational
infrastructure• Safety approach• The safety case* and safetyassessment• Elements in a stepwise approach to
the development of a geologicaldisposal facility*Safety Case: A comprehensive evaluation of the safety assessment• Findings of a safety assessment and a statement of confidence in thesefindings.
• Addressing weak points of the safety assessment and how to overcomethemTimeline of the development of a geologicaldisposal facility (IAEA Safety Standard SSG-14)

Requirements for safe disposal• R15-19 Steps in disposal:−Site characterization… to support a general understanding of
the characteristics of the site and how the site will evolve overtime−Design… the facility shall be designed to provide operational
and post-closure safety−Construction… the facility shall be constructed in accordancewith the design in the safety case
−Operation… the facility shall be operated in accordance with thelicence, relevant regulatory requirements and Waste AcceptanceCriteria−Closure… the facility shall be closed to provide the safetyfunctions shown in the safety case to be important for safety
10Safety assessment• Evaluating the overall performance of adisposal system, including−Host rock−Confinement area−Overlaying rock−Biosphere• Systematic assessment of radiation
hazards−Quantifying its potential radiological impact−both in operation and after closure.

11IAEA Specific Safety Guide 14 (SSG-14)

Geological Disposal Facilities for Radioactive Waste

BIOSPHERERiver
GEOSPHERE

Isolation
DISPOSAL

Transport
limitation
Seals

EXCAVATED DAMAGED ZONEWASTE PACKAGES

Confinement

MatrixOverpack

Well

Safety Assessment –A complex document

Biosphere in the post-closure period of adisposal facility
BIOSPHERERiver
GEOSPHERE

Isolation
DISPOSALEXCAVATEDDAMAGED ZONE

Transport
limitation
Seals

WASTE PACKAGES

Confinement

MatrixOverpackWell

Radiation protection in the post-closure period
Safety objectives− The safety objective is• to site, design, construct, operate and close a disposal facility• so that protection after its closure is optimized, social and economic factors
being taken into account.

− A reasonable assurance also has to be provided• that doses and risks …. in the long term will not exceed the dose constraints or
risk constraints that were used as design criteria.

Criteria− The dose limit for members of the public for doses from all planned exposure
situations is an effective dose of 1 mSv/a.
• This criteria should not to be exceeded in the future.
− To comply with this dose limit, the calculated dose or risk …. does not exceed adose constraint of 0.3 mSv/a or a risk constraint of the order of 10–5 peryear

Sweden• Risk constraint: 10-6 per year (ca. 20 µSv /y)*Criteria innational
disposalfacility
projects*Exposure from natural
background: 2.4 mSv/y• Time frame after closure− First 1000: Quantitative assessments− > 1000 y: Sequence of possible developments− Assessment as long time as barrier functions arerequired, but at least 10 000 y• Finland− Dose criteria• Dose to the most exposed people …. below of0.1 mSv/y• Average doses to other people shall remain
insignificantly low.
− Time frame after closure• Several 1000 y• Then: constraints on radioactive releases tothe environment• Releases can be averaged over one 1000 years.

France• Risk constraint: 0.25 mSv/a• Time frame after closure

Criteria innational
disposalfacility
projects(cont.)− 10000 years for safety demonstration

Germany• Dose criteria for HLW disposal facility− 10 µSv per year (still under discussion)• Time frame after closure (still underdiscussion)− 10 000 years: Detailed assessment− 1 million (!) years: A more stylizedassessment

Safety Guide
SSG-14
Appendix II:
Post-Closure
SafetyAssessment• Radiation exposure is the major safety
issue− Develop confidence in modelling− Reasonable conservatism• Any approach to make that acceptanceeasier will be a long term benefit− Acceptance can be the most difficult aspectof an assessment• An approach which balances− simplicity, conservatism and realism
is likely to be the best starting point forassessments.

Compliancewith safety
objectivesand criteria• In estimating doses to individuals in the future
due to a disposal facility,− …. people will be present locally,− ….People make some use of local resourcesthat may contain radionuclides originatingfrom the waste in the disposal facility.
• It is not possible to predict the behaviour ofpeople in the future with any certainty,− Its representation in assessment models isnecessarily stylized.

• The rationale and possible approaches to themodelling of the biosphere and the estimation ofdoses arising from waste disposal facilities havebeen considered in the IAEA BIOMASS Project.

Assessment of potential exposures after closure of the facility

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The IAEA
BIOMASS
Project(1998-2003)

Conclusions• IAEA has developed Safety Standards onthe disposal of radioactive waste• The safety assessment for a waste disposal
facility has to cover all components andaspects of a facility−Host rock, waste packages in theconfinement, geology and hydrology,
exposures to people in the biosphere• Radiological criteria in the post-closure
period−Well below 1 mSv/a−Time frame to be considered up to amillion years• IAEA developed a methodology to set up
assessment models for exposures in thefar future