P2. Overview of the IAEA’s Project on -...

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

[email protected]

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


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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


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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”


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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)


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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* Comment: NS-G-1.2 is superseded by SSG-2, where such link is not included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


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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


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OUTPUT

A formal TM report has been produced

● Outputs of WGs

● Questionnaires responded

● Papers

● Conclusions and recommendations for IAEA activities


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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


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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


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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)


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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


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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


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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


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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)


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SUGGESTED HIERARCHY OF SAFETY GOALS (1/5)


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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


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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


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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


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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


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BASIC TYPES OF SAFETY GOALS


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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


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


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


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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


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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.


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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


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THANK YOU FOR YOUR ATTENTION

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