Overview of IAEA's Projects on Safety Goals and … of IAEA's Projects on Safety Goals and Integrated Risk Informed Decision Making ... establishing and use of Safety Goals ... is

International Atomic Energy Agency

Overview of IAEA's Projects on Safety Goals and

Integrated Risk Informed Decision Making

Presented by: Irina Kuzmina, PhD, Safety Officer

Safety Assessment Section/ Division of Nuclear Installation Safety/

Department of Nuclear Safety

[email protected]

1st Consultants’ Meeting on the INPRO Collaborative Project:

Review of Innovative Reactor Concepts for Prevention of Severe Accidents and Mitigation of

their Consequences (RISC)

31 March – 2 April 2014, IAEA, Vienna, Austria


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HIGHLIGHTS

■ Safety Goals

● Background, status, high-level overview of the

contents

■ Integrated Risk Informed Decision Making

(IRIDM)

● Background, status, high-level overview of the

contents

� IAEA-TECDOC publication series


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Safety Goals


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WHAT DO WE MEANT BY SAFETY GOALS?

� Safety Goals for nuclear installations: characteristics aimed to assist in answering the fundamental question: “How safe is safe enough?”

� Generally, Safety Goals provide a measure of sufficiency/adequacy of safety provisionsembedded in the design of a nuclear installation and its operational process


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Safety Margins

CHARACTERIZATION OF SAFETY GOALS

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

QUANTITATIVE

Limits for

respective

RISK METRICS -

frequencies of

undesirable

consequences

(events/time unit)


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Safety

Assessment

SAFETY

GOALS

Safety

Provisions


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SAFETY FUNDAMENTALS (1/2)

The Fundamental Safety Objectiveis

to protect people and the environment from harmful

effects of ionizing radiation

� ‘Safety’ means the protection of people and the environment against radiation risks

�Ten safety principles have been formulated, on the basis of which safety requirements are developed and safety measures are to be implemented in order to achieve the fundamental safety objective


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SAFETY FUNDAMENTALS (2/2)

Principle 6: Limitation of risks to individuals

“Measures for controlling radiation risks must ensure that no individual bears an unacceptable risk of harm”

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) provided

Implications:

SAFETY GOALS


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INSAG-12

Basic Safety Principles for Nuclear Power

Plants, 75-INSAG-3 Rev.1, INSAG-12, A

report by the International Nuclear Safety

Advisory Group, IAEA, Vienna, 1999

� Revision of the original 75-INSAG-3

(1988)

� Qualitative safety concepts,

Defense-in-Depth emphasized

� Current reference IAEA publication

for probabilistic safety goals


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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 the consideration 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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CITATION FROM INSAG-12 ON SAFETY GOALS

25. For future NPPs, consideration of multiple failures and severe accidents will be achieved in a more systematic and complete way from the design stage. This will include improving accident prevention (for example, reduced common mode failures, reduced complexity, increased inspectability and maintainability, extended use of passive features, optimized human–machine interface, extended use of information technology) and further reducing the possibilities and consequences of off-site radioactive releases.

26. In the safety technology of nuclear power, overall risk is obtained by considering the entire set of potential events and their respective probabilities and consequences. The technical safety objective for accidents is to apply accident prevention, management and mitigation measures in such a way that overall risk is very low and no accident sequence, whether it is of low probability or high probability, contributes to risk in a way that is excessive in comparison with other sequences.

27. The target for existing NPPs L is a frequency of occurrence of severe core damage that is below about 10–4 events per plant operating year. Severe accident management and mitigation measures could reduce by a factor of at least ten the probability of large off-site releases requiring short term off-site response. Application of all safety principles and the objectives (of para. 25) to future plants could lead to the achievement of an improved goal of not more than 10–5 severe core damage events per plant operating year. Another objective for these future plants is the practical elimination of accident sequences that could lead to large early radioactive releases, whereas severe accidents that could imply late containment failure would be considered in the design process with realistic assumptions and best estimate analyses so that their consequences would necessitate only protective measures limited in area and in time.


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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

■ Producing guidance on

establishing and use of

Safety Goals recommended


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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

� Hierarchical structure


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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 (1/2)

1. INTRODUCTION

2. DISCUSSION ON THE BACKGROUND AND BENEFITS OF A SAFETY GOALS

FRAMEWORK

● Safety Goals Definition

● A Framework for Safety Goals

● Relationship to IAEA Safety Standards

● Global Harmonisation

● Public Understanding and Communication

● Use of Safety Goals by Stakeholders

● Safety Goals Framework and Safety Performance Indicators

3. CHARACTERISTICS AND ASPECTS OF A SAFETY GOALS FRAMEWORK

● Considerations from the Technical Meeting, April 2011

● Safety Goals and IAEA Safety Standards Framework

● Safety Goals Framework Characteristics

● Aspects to be Considered in Developing a Safety Goals Framework

● Communication


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OUTLINE (2/2)

4. A GENERAL FRAMEWORK FOR SAFETY GOALS

● Basic Types of Safety Goals

● Hierarchical Approach to Safety Goals

5. DERIVATION OF SAFETY GOALS

● The Roles of Stakeholders Involved in the Definition of Safety Goals

● Safety Goals within the Framework

● Organising the Safety Goals defined within the Framework

6. APPLICATIONS OF A SAFETY GOALS FRAMEWORK

● Compliance Assessment

● Regulatory and Licensee Applications

● Use of the Safety Goals Framework in Integrated Risk Informed Decision Making

7. CONCLUDING REMARKS

APPENDIX 1 GLOSSARY

APPENDIX 2 SPECIFIC EXAMPLES OF SAFETY GOALS FRAMEWORK


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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


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HIERARCHICAL LEVELS OF SAFETY GOALS (1/4)

Level Formulation Notes

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 (or 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

Qualitative safety goals interpreting what is needed to ensure adequate protection

Includes interpretation of the top level safety goal in risk terms for accident conditions. 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

Technology-neutral site-wide safety goals based on proven approaches and good practices to achieve the upper level safety goals (e.g. definition of general requirements at 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 that all nuclear installations/ facilities at the jointly meet the respective intermediate 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 • Society & site-wide

• Technology-neutral

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

INTERMEDIATE LEVEL SAFETY GOALS:


• Site-wide


Qualitative

O1-Q1 Management, leadership and safety culture

Deterministic quantitative

O1-D1 To meet ICRP

criteria for workers by providing adequate radiation protection

measures

K K K L Qualitative

A1-Q1 Maintaining effective

defence-in-depth


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 for

land, site-level

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

LOW LEVEL SAFETY GOALS: Providing necessary specific safety provisions for all facilities and installations at the site • Technology-specific

• Facility and installation-specific

K K K K Deterministic quantitative

A1-Q2-INST1(D1) – max fuel clad

temp. for INST1

A1-Q2-INST1(D2) – K for INST1

----------------------------------


temp. for INST2



• LERF for each installation:

A1-P1-INST1(LERF),

A1-P1-INST2(LERF),

• Supplemental goals on CDF as applicable:

A1-P1-INST1(CDF ),

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 K

Vital area identification at

facility level


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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 • Site-wide


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

INTERMEDIATE LEVEL SAFETY GOALS:


• Site-wide


Qualitative

O1-Q1 Management, leadership and safety culture


O1-D1 To meet ICRP

criteria for workers by

providing adequate radiation protection

measures

K K K L Qualitative

A1-Q1 Maintaining effective

defence-in-depth


A1-D1 Maintaining

allowed doses for

workers in DBAs


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 for land, site-level

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

LOW LEVEL SAFETY GOALS: Providing necessary specific safety provisions for all facilities and installations at the site • Technology-specific

• Facility and installation-specific

K K K K Deterministic quantitative


temp. for INST1


----------------------------------


temp. for INST2



• LERF for each installation:

A1-P1-INST1(LERF),

A1-P1-INST2(LERF),

• Supplemental goals on

CDF as applicable:

A1-P1-INST1(CDF ),

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 K

Vital area

identification at facility level


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RECENT ACTIVITIES

■ Second Technical Meeting to review the preliminary draft TECDOC08-12 July 2013, Vienna, Austria

� A formal report produced

� The suggested structure is seen adequate + recommendations

� Helpful for developing countries (holistic view) & benchmarking the existing safety goals frameworks

� Wider informing the international community is useful

■ CMs: July 15-19, December 2-6, 2013� Addressing recommendations of the 2d TM

� Updated final draft soon


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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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Integrated Risk Informed Decision Making

• INSAG-25

• Guidance (TECDOC)


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� The Integrated Risk Informed Decision Making (IRIDM)

process is a structured process in which all the

insights and requirements relating to an operational,

safety or a regulatory issue are considered in reaching

a balanced and optimized decision

� The main goal of IRIDM is to ensure that any decision

which might affect nuclear safety is optimized without

unduly limiting the conduct of safe operation of the

nuclear power plant

IRIDM PROCESS


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EXAMPLES OF IRIDM APPLICATIONS

� An integrated approach can be applied to making decisions on operational and safety issues of a nuclear power plant

� These typically include

● Hardware Modifications & Procedural Changes

� Plant modifications and backfittings

� Emergency operating procedures

� Accident management measures, etc.

● Changes to Tech Specs (Operation Limits and Conditions)

� Optimization of on-line maintenance practices

� Changes to allowed outage times

� Optimization of testing intervals & arrangements

� Plant configuration management, etc.

● Exemptions from Tech Specs, etc.


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INSAG-25

INSAG-25 published in 2011

• Identifies the basic framework

• Sets out the principles for

application

• Define the key elements of

IRIDM


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IRIDM FRAMEWORK (INSAG-25)

Logical, reproducible, verifiable,

uncertainties addressed


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� Improved safety

● By taking each factor influencing safety into account in a

decision and its implementation

� Increased installation performance, operational

flexibility, cost effectiveness of operations

� Reduced radiation exposure

● By focusing maintenance on more risk-significant areas and

reducing unnecessary activities in high radiation areas

� Etc.

IRIDM BENEFITS


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TECDOC “IRIDM GUIDANCE”

� Objective: to suggest approaches to integrate the

results of DSA and PSA as well as other important

aspects to make sound, optimum, and safe decisions

● Follows the main principles presented in INSAG-25

● Provides detailed information/guidance on the key

elements of IRIDM and their integration

● Provides examples illustrating how the decisions can be

made or have been made using a structured IRIDM

process

● Explain issues not elaborated in the INSAG-25� Establishment of the IRIDM process

� Integration of inputs

� Treatment of uncertainties, etc.

� IAEA technical lead – A.Lyubarskiy, SAS/NSNI ([email protected])


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IRIDM FRAMEWORK (NEW TECDOC)

Examples (annexes)

Discussion on uncertainty


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IRIDM FRAMEWORK (NEW TECDOC)

Examples (annexes)

Discussion on unceratinty


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STRUCTURE OF THE TECDOC

1. INTRODUCTION

2. GENERAL OVERVIEW OF THE IRIDM PROCESS

3. DESCRIPTION OF THE IRIDM WORK FLOW

4. PREPARATION FOR THE ASSESSMENT OF THE INPUTS

5. ASSESSMENT, INTEGRATION AND DOCUMENTATION

6. APPROVAL, IMPLEMENTATION AND QUALITY ASSURANCE

7. SETTING UP A FORMAL IRIDM CAPABILITY

8. REFERENCES

ANNEXES 1 to 8 – EXAMPLES & DETAILED GUIDANCE


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SECTION 7: SETTING UP FORMAL IRIDM CAPABILITY


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SUMMARY

■ SAS/NSNI is currently developing two publications in

the IAEA-TECDOC series:

1. ‘Development and Application of a Safety Goals

Framework for Nuclear Installations’ and

2. ‘Integrated Risk Informed Decision Making Guidance’

■ Provide a structured, comprehensive and logical

framework and a process to promote making more

transparent and justifiable decisions to achieve

adequate protection of people and the environment

against radiation risks

■ Advanced development stage (publishing ~ end 2014)


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THANK YOU FOR YOUR ATTENTION

Documents

Overview of IAEA's Projects on Safety Goals and … of IAEA's Projects on Safety Goals and Integrated Risk Informed Decision Making ... establishing and use of Safety Goals ... is