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International Atomic Energy Agency
P2. Overview of the IAEA’s Project on
Safety Goals
Presented by: Irina Kuzmina, Safety Officer
Safety Assessment Section/ Division of Nuclear Installation Safety/
Department of Nuclear Safety and Security
Technical Meeting on Development of a TECDOC on
Development and Application of a Safety Goals Framework for Nuclear Installations
Vienna, Austria
July 8-12, 2013
International Atomic Energy Agency
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HIGHLIGHTS
■ Background
● IAEA Safety Standards
● INSAG report
■ Overview of the developments under the IAEA project
on Safety Goals
● TM in April 2011
● CMs
● Outputs
International Atomic Energy Agency
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RELEVANT STATEMENTS FROM THE SAFETY FUNDAMENTALS
The fundamental safety objective is
to protect people and the environment from
harmful effects of ionizing radiation
1) Risk associated with nuclear installations needs to be assessed
2) Guidance (criteria) for ‘unacceptable risk’ need to be
established
3) Relevant measures (design features and procedures) to be provided to control risk
Implications:
SAFETY GOALS
Principle 6: Limitation of risks to individuals
“Measures for controlling radiation risks must ensure that no individual bears an unacceptable risk of harm”
International Atomic Energy Agency
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Safety Margins
SAFETY
GOALS
Defense-in-Depth • Multiple barriers and
levels of protection
• Diversity and
redundancy within and
between safety
systems
• Single failure criterion
• Postulated initiating
events, etc.
QUALITATIVE
0.0E+00
1.0E-05
2.0E-05
3.0E-05
4.0E-05
5.0E-05
6.0E-05
7.0E-05
8.0E-05
9.0E-05
1.0E-04
PROBABILISTIC
QUANTITATIVE
Limits for
respective
RISK METRICS -
frequencies of
undesirable
consequences
(events/time unit)
International Atomic Energy Agency
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ILLUSTRATION OF THE CONCEPT OF NUMERICAL SAFETY GOALS
CONSIDERED IN INSAG-12 & NS-G-1.2*
* Comment: NS-G-1.2 is superseded by SSG-2, where such link is not included
0.0E+00
1.0E-05
2.0E-05
3.0E-05
4.0E-05
5.0E-05
6.0E-05
7.0E-05
8.0E-05
9.0E-05
1.0E-04CDF for
operating NPPs
CDF for new NPPs
0.0E+00
1.0E-06
2.0E-06
3.0E-06
4.0E-06
5.0E-06
6.0E-06
7.0E-06
8.0E-06
9.0E-06
1.0E-05LRF for operating
NPPs
Practical elimination of accident sequences
that could lead to large early radioactive
releases for new NPPs (NS-G-1.2)*
Core Damage Frequency (CDF) Large Release Frequency (LRF)
1/y
1/y
International Atomic Energy Agency
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IAEA TECHNICAL MEETING ON
SAFETY GOALS IN APPLICATION
TO NUCLEAR INSTALLATIONS
TM Objective
● Provide international forum for presentations and discussions on the current practices in establishing and use of Safety Goals for nuclear installations
● To contribute to outlining the way forward
TM Summary
● Some 40 attendees from 23 countries and 5 international organizations - regulators, operators, designers, consultants, and TSOs
● 30 presentations and papers
● Two working groups:
WG1: General Framework for Safety Goals and Methodologies/Processes for Compliance Assessment
WG2: Process of Derivation of Low-Tier Quantitative Safety Goals and Qualitative and Quantitative Safety Goals Specification
● Questionnaire on national framework for Safety Goals with 20 responses
International Atomic Energy Agency
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OUTPUT
A formal TM report has been produced
● Outputs of WGs
● Questionnaires responded
● Papers
● Conclusions and recommendations for IAEA activities
International Atomic Energy Agency
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OBSERVATIONS
■ Surveys show that there is a variety of approaches
relating to establishment and use of Safety Goals in
Member States, which often include qualitative
considerations and quantitative risk metrics
■ Recent international projects on Safety Goals being
pursued by different expert groups [e.g. MDEP, WENRA,
Nordic PSA Group (NPSAG)] produced recommendations
■ Growing importance of establishing a technically
consistent holistic framework for Safety Goals for NPPs
and other nuclear installations on the basis of synergetic
consideration of qualitative concepts and quantitative risk
metrics
International Atomic Energy Agency
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RECOMMENDATIONS
Five areas were recommended by the TM where IAEA should
consider producing guidance (the formal TM report):
1. Develop a hierarchical approach for Safety Goals
2. Clarify interfaces between the Fundamental Safety
Objectives, Safety Principles, Safety Requirements and the
proposed framework for Safety Goals
3. Develop a methodology to derive lower-tier goals in a
consistent and coherent manner
4. Develop guidance on methods and approaches to assess the
degree of compliance with the full spectrum of Safety Goals and
a comprehensive review methodology
5. Develop an approach to using Safety Goals
International Atomic Energy Agency
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CONTINUED WORK AFTER TM APRIL 2011
■ A series of consultant meetings (2012-2013) to develop a draft TECDOC -
“Development and Application of a Safety Goals Framework for Nuclear Installations”
■ Overall Objective: to promote a greater harmonization of the use of Safety Goals in Member States
■ Specific Objectives: to provide guidance for establishing a formal framework for Safety Goals and compliance assessment
______________
■ Drafting TECDOC - CM participants: • Irina Kuzmina (IAEA)
• Andy Ashworth (AECL, Canada)
• Heinz Peter Berg (BfS, Germany)
• Nigel Buttery (EdF Energy, UK)
• Michael Knochenhauer (Lloyd’s Register Scandpower, Sweden)
• Geoff Vaughan (ONR, UK)
• See-Meng Wong (NRC, USA)
International Atomic Energy Agency
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OUTLINE
1. INTRODUCTION
2. DISCUSSION ON OBJECTIVES AND BENEFITS OF INTRODUCING A
SAFETY GOALS FRAMEWORK
3. CONCEPTS RELATED TO THE SAFETY GOALS FRAMEWORK
4. A GENERAL FRAMEWORK FOR SAFETY GOALS
5. DERIVATION OF SAFETY GOALS WITHIN THE HIERARCHY
6. Section 6 APPLICATION OF THE SAFETY GOAL STRUCTURE AND
COMPLIANCE ASSESSMENT
7. CONCLUSIONS
APPENDIX 1 GLOSSARY
APPENDIX 2 SPECIFIC EXAMPLES OF SAFETY GOALS FRAMEWORK
APPENDIX 3 DEVELOPMENT OF USNRC SAFETY GOALS FOR LIGHT
WATER REACTORS
International Atomic Energy Agency
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DEVELOPMENT OF A SAFETY GOALS HIERARCHY
Considers work within
the CM teams as well
as the hierarcies of
Safety Goals
suggested in the
MDEP and NPSAG
projects on safety
goals
International Atomic Energy Agency
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DEVELOPMENTS BY MULTINATIONAL DESIGN
EVALUATION PROJECT - MDEP
The MDEP work attempted to set
out a hierarchical approach
● Top level = Fundamental Safety
Objective of the IAEA of protecting
people from radiation risks
● Second tier is based partly on the
basic defence-in-depth approach,
probably still to some extent
technology independent
● From the upper levels the
intention is to develop lower-level
goals, eventually technology
specific
Top
Level
Safety Goal
High Level Safety Goals
(DiD and Risk Goals)
Lower Level Safety Goals and Targets
(Deterministic and probabilistic)
Technology Specific Safety Targets
Within MDEP, a group was tasked with considering how to harmonise Safety Goals
International Atomic Energy Agency
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HIERARCHY SUGGESTED IN NORDIC PSA GROUP
PROJECT - NPSAG
As part of the NPSAG project on probabilistic Safety Goals, a hierarchy was suggested
There are four levels :
● Society level (legislation expressing high-level requirements)
● Intermediate level (interpretation of legal requirements in a way that allows quantification)
● Technical level (quantitative requirements)
High level (corresponding to PSA Level 1, 2 and 3)
Low level (corresponding to safety systems and functions)
International Atomic Energy Agency
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SUGGESTED HIERARCHY OF SAFETY GOALS (2/5)
Level Formulation Description
Top Level
Primary Safety Goal
Protecting people and the environment from harmful effect of ionizing radiation
Primary safety goal as set out in SF-1 and society level safety goals as defined in national legislation or regulations
International Atomic Energy Agency
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SUGGESTED HIERARCHY OF SAFETY GOALS (3/5)
Level Formulation Description
Upper Level
Adequate Protection
Ensuring adequate protection in all operational modes of all facilities and installations at the site
Interpretation of the top level safety goal in risk terms. This is often done by comparison with the levels of risks coming from other involuntary sources of risk
International Atomic Energy Agency
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SUGGESTED HIERARCHY OF SAFETY GOALS (4/5)
Level Formulation Description
Intermediate Level
General Safety Provisions
Providing necessary safety provisions including technical and organizational measures based on proven approaches and good practices to ensure adequate protection
Proven approaches and good practices to achieve the higher level safety goals as well as definition of general requirements on site level
International Atomic Energy Agency
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SUGGESTED HIERARCHY OF SAFETY GOALS (5/5)
Level Formulation Description
Low Level
Specific Safety Provisions
Providing necessary specific safety provisions for all facilities and installations at the site
Technology and facility specific safety goals aimed at assuring the nuclear installation meets the higher level safety goals
International Atomic Energy Agency
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An Example of Hierarchy of Safety Goals for Nuclear Installations
TOP LEVEL - PRIMARY SAFETY GOAL: To protect people and the environment from harmful effects of ionizing radiation Society-wide
UPPER LEVEL SAFETY GOALS: Ensuring adequate protection in all operational modes of all facilities and installations at the site
Operational states Accident conditions
O1 To protect workers, the public and the
environment
O2 To provide
design features for
security
O3 To minimize radioactive
waste
O4 To provide
design features to facilitate
decommis-sioning
A1 Risk to life and health of people from the facilities and installations
located at the site should be low comparing with risk from other sources to which an individual is generally exposed
A2 Large off-site releases leading to land
interdiction should be practically eliminated
A3 Safety-security
interface should be addressed
A4 Emergency
response should be provided
Site-wide
Technology-
neutral
INTERMEDIATE LEVEL SAFETY GOALS:
Providing necessary safety provisions including technical and organizational measures based on proven approaches and good practices to ensure adequate protection
Qualitative
O1-Q1 Management, leadership and safety culture
Deterministic quantitative
O1-D1 To meet ICRP criteria for
workers by providing adequate radiation
protection measures
… … … … Qualitative
A1-Q1 Maintaining effective
defense-in-depth
Deterministic quantitative
A1-D1 Maintaining
allowed doses for workers in DBAs
Probabilistic quantitative
A1-P1 Overall L(E)RF for the site for all events and
hazards
Qualitative
A2-Q1 Providing effective
SAM design features and SAMG
at the site level
Probabilistic quantitative
A2-P1 Probabilistic
interpretation of practically eliminated
A3-Q1 Vital area
identification at the site level
A4-Q1 Detailed
emergency plan
O1-D2 To meet ICRP criteria for
discharges to the environment by providing adequate measures for
controlling the discharges
A1-Q2 Maintaining sufficient
safety margins
A1-D2 Maintaining
allowed discharges to the environment in
DBAs
A1-P2 Frequencies of external hazards/ magnitudes for design of site protective
features
A2-P2 Food ban
radioactivity levels and accepted frequency
A4-D1 Food ban levels
A1-Q3 Providing sufficient
redundancy and diversity to comply with single failure criterion
A1-D3 Containment
withstanding the crash of a
specified size aircraft
A2-P3 Habitation
radioactivity levels and accepted frequency
A4-D2 Habitation
radioactivity levels
Site-wide
Technology-
neutral
LOW LEVEL SAFETY GOALS: Providing necessary specific safety provisions for all facilities and installations at the site
… … … … Deterministic quantitative
A1-Q2-INST1(D1) – max fuel clad
temp. for INST1
A1-Q2-INST1(D2) – … for INST1
----------------------------------
A1-Q2-INST2(D1) – max fuel clad
temp. for INST2
A1-Q2-INST2(D2) – … for INST2
Qualitative
A2-Q1-INST1(SAMG)
A2-Q1-
INST2(SAMG)
Providing effective SAM design
measures and SAMG at the facility
level
A3-Q1-INST1
A3-Q1-INST12 …
Vital area identification at
facility level
A1-Q3-INST1 - required three trains of safety systems
Probabilistic quantitative
LERF for each installation:
A1-P1-INST1(LERF),
A1-P1-INST2(LERF),
Supplemental goals on CDF as applicable:
A1-P1-INST1(CDF ),
A1-P1-INST2(CDF), …
Instantaneous risk limit
Technology-
specific
Facility and
installation-specific
International Atomic Energy Agency
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ANTICIPATED REMAINING WORK TO DEVELOP TECDOC
■ Second Technical Meeting to discuss draft TECDOC 08-12 July 2013, Vienna, Austria
■ CM July 15-19, 2013 Addressing recommendations of the 2d TM, finalization of the TECDOC
International Atomic Energy Agency
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ISSUES NEEDING FURTHER CONSIDERATION
‘Quantification’ is asked by Member States for the terms :
■Extremely unlikely
■High level of confidence
What should be the basis for these?
Practically eliminated:
The possibility of certain conditions occurring is
considered to have been practically eliminated if it is
physically impossible for the conditions to occur or if
the conditions can be considered with a high level of
confidence to be extremely unlikely to arise.
International Atomic Energy Agency
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SUMMARY
■ Following the recommendations of Member States, the
IAEA is developing a TECDOC aimed at:
• Suggesting an approach for establishing a robust framework
for Safety Goals for nuclear installations, and
• Providing guidance on compliance assessment
■ The TM will review and further develop the TECDOC
• High interest
• Important topic
■ Publishing the TECDOC is anticipated end 2013 – beginning
2014