plant life management and r&d activities in japan … · plant life management and r&d...

Plant Life Management and R&D Activities in Japan

after the Fukushima Daiichi Accident

Prof. Naoto Sekimura, Dr.

Vice President

Professor, Department of Nuclear Engineering and Management

The University of Tokyo

Associate Member of Science Council of Japan

Chairperson, Nuclear Reactor Safety Examination Committee, NRA Japan

Chairperson, Nuclear Safety Division

Chairperson, Nuclear Standard Committee

Atomic Energy Society of Japan

October 25, 2017

PLiM 2017, Lyon

Contents

1. Introduction

• Current Status of Nuclear Power Policy and NPPs in Japan

• Change in Regulatory Requirements

2. Ageing Management and Long Term Operation of NPPs

• Issues and Projects on Materials and Their Systems

• Decommissioning of Fukushima Daiichi NPPs

• Materials and Components from Decommissioning Reactors

3. Future R&D and Collaboration

• Research Roadmap

• Future International Collaboration

4. Summary

2

Current Status of Strategic Energy Plan in Japan

� 4th Strategic Energy Plan has been determined by the

Government on April 11, 2014, to provide basic lines

of energy policy for these 20 years.

� “Nuclear power is an important baseload

electricity source.”

� Long Term Plan on April 27, 2015

� Contribution of nuclear power in 2030

: 20-22% of total electricity source

� Operation of more than 30 nuclear reactors in Japan

� Long term operation

� Possible replacements3

Situations Surrounding the Use of Nuclear Power in Japan

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2025 2030 2050

Interim Storage

Reprocessing

MOX Fuel Processing

Fast Reactors

Electric Market Reform

Nuclear Power

Ov

ers

ea

s

Nu

cle

aP

ow

er

Nuclear Fuel

Cycle

Fukushima Daiichi

New RegulatoryRequirements

Related to Climate Change

Voluntary Efforts

to Improve Safety

Decommissioning

Strategic Energy Plan

Jap

an

New Regulatory

Standards

(July 8, 2013)

Accident at Fukushima Daiichi

Nuclear Power Station

(March 11, 2011)

Fuel Debris Removal

Completion of the Decommission

Mutsu Interim Storage Facility

Rokkasho MOX Fuel Processing Plant

Full Retail Competition

Legal Unbundling of Transmission and Distribution Sectors

Practical application of fast reactors

2nd commitment period of the Kyoto Protocol

Establishment of the Organization for Cross Regional Coordinationof Transmission Operators

Greenhouse gas reduction

Whole world: half

Developed counties: >80%

Rokkasho Reprocessing Plant

Practical Application of

Fast Reactors

Restart

Decommissioning of Reactors

Safety Improvement Evaluation

Submitting Intended Nationally Determined Contribution before COP 21

Total capacity of nuclear Power in the world :to grow by about 10 to 90% by 2030 about 10 to 190% by 2050 (IAEA)

and by about 60% by 2040 (IEA)

Establishment of Japan Nuclear Safety Institute (JANSI) (Nov. 15, 2012)

Proposals for Voluntary and Continuous Improvement of Nuclear Safety (May 30, 2014)

Establishment of Nuclear Risk Research Center (NRRC) (Oct. 1, 2014)

Basic line of Energy policy with a view to an energy supply-demand Structure for the Mid to Longterm (20 years)- - -4th Strategic Energy Plan (April 11, 2014)

Establishment of a Proper Risk Governance Framework

4

The NRA (Nuclear Regulatory Authority) implements new regulatory

systems stipulated in the amended Nuclear Regulation Act ;

�Regulation taking severe accidents into consideration

• Legally request severe accident measures to the licensees

� Introduction of back-fitting system : Regulation applying latest scientific/technical knowledge on safety issues to existing facilities

• Apply new technical requirements to existing licensed nuclear facilities as a legal obligation

� An operation limit of 40 years to deal with aged reactors

• As an exception, extension (<20 years) will be approved, only whencompliance with the regulatory standards by the Government Order is confirmed.

� Special safety regulation in Fukushima Daiichi site

New Nuclear Regulation Systems in Japan Became Effective from July 8, 2013

5

6

Prevention of Core Damage

Seismic/Tsunami Resistance

Natural phenomena

<Previous Requirements>

Reliability of power supply

Function of other SCCs

Ultimate heat sink

Fire protection

Seismic/Tsunami resistance

Ultimate Heat Sink

Fire Protection

Function of other SCCs

Reliability of Components

Natural Phenomena

Prevention of CV Failure

Suppression of Release of Radioactive Materials

Specialized Safety Facility

Reliability of components Reliability of Power Supply

<Current Requirements>

Re

info

rce

dS

ev

ere

Acc

ide

nt

Me

asu

res

(Ne

w)

Re

info

rce

d

3rd Layer of DiD

Requirements for Beyond DBA

4th Layer of DiD

Current Regulatory Requirements in Japan

6

7

Regulatory Systems for Inspection, Periodic Safety Reviewand Ageing Management in Japan

Evaluation of Safety Improvements (Strengthened Periodic Safety Review)

5 Years 5 Years5 Years5 Years

Ageing Management Technical Evaluation (AMTE)before 30 years for Continued Operation

30 Years 10 Years 10 Years

Back Fitting / Regulatory Inspection (ROP)

Start of Commercial Operation

7

10 Years

40 Years

5 Years 5 Years5 Years5 Years

Re-evaluation Every 10 Years

Extended Operation Period

5 Years

Extension can be approved only once up to 60 yeas

8

0

200

400

600

800

1000

1200

1400

1600

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

BWR : 22 unitsPWR : 20 units

Decommissioning BWR

1F-1

1F-2 1F-3 1F-51F-4

1F-6

1F : Fukushima-Daiichi

H : Hamaoka

M : MihamaGCR ATR

H-1

H-2

Tsuruga-1

M-1

M-2

Shimane-1

Genkai-1 Ikata-1

Current Status of Nuclear Power Plants in Japan


Ele

ctri

cal

Ou

tpu

t (M

We

)

Decommissioning PWR

8

Sendai-1 Sendai-2 Ikata-3

Takahama-3,4

Takahama

Mihama

Ohi

DecommissioningUnit 1

Unit 1

Unit 1

Unit 2

Unit 2

Unit 2

Unit 3

Unit 3

Unit 3

Unit 4

Unit 4

30 years 40 years

2017

Status of PWRs in KEPCO

Beyond 40 years of operation

Under operation

Re-starting very soon

9

826MWe

826MWe

826MWe

340MWe

500MWe

870MWe

870MWe

1180MWe

1180MWe

1175MWe

1175MWe

� Special Inspections are required in addition to;

• Meet new regulatory requirements

• Ageing Management Technical Evaluation for every 10 years

and Maintenance Program

Special Additional Inspectionsfor Long Term Operation beyond 40 years up to 60 years

Regulatory Requirements of Special Additional Inspections

Components Current Inspection Additional Inspection

Reactor Pressure VesselUltrasonic Tests of

Welded Zone

100% UT Examination of Base

Metal in addition to Welded Zone

Primary Containment Vessel (Steel) Leak Rate Tests

Visual Test

(Appearance of coating film)

Civil Concrete Structure Visual Tests & NDT

Core Sampling

(Strength, Neutralization, Salt

intrusion, etc.) 10

RCS pipe nozzle corner

Core region of RPV

Safe end dissimilar metal joint

RPV head nozzle

UT (base metal)

VTDirect visual inspection from penetration OD

ECT (cladding)

UT (welds)

UT (base metal/welds)

SCC in 600 series Ni-base alloy →Replacement of RV head

SCC in 600 series Ni-base alloy → Apply Water Jet Peening (WJP)

UT (dissimilar metal joint)

Leak test

Special Additional Inspection of Pressure Vessel

BMI nozzle

Nozzle ID: ECTWelds: VT

(video camera)

Blue character ; Routine inspectionRed character; Special additional inspection

11

FY 2014 2015 2016 2017 2018 2019 2020

Takahama

1 & 2

Mihama

3・Reinforcement of SFP & SFP Re-racking

・Fire Protection Measures

・Replacement of Core Internals

・Replacement of Main Control Panels, etc.

・Installation of CV Upper Shielding

・Fire Protection Measures

・Replacement of Main Control Panels

・Relocation of Seawater Pipes in unit 2, etc.

Safety screening review

against new regulatory

requirements

Review on extension of

operation period

Special

inspection

▼6/20 Approved

▼4/20 Approval of change in reactor installation license

▼6/10 Approval of construction plan

Additional Safety Measures

Pre

-serv

ice in

spectio

n

Resta

rt

Safety screening review

against new regulatory

requirements

Review on extension of

operation period

Special

inspection

▼11/16 Approved

▼10/5 Approval of change in reactor installation license

▼10/26 Approval of construction plan

Additional Safety Measures for Extended Operation

Pre

-serv

ice in

spectio

n

Resta

rt

Additional Safety Measures

12

Pressurizer

Reactor vessel

Concrete structures

Steam generator

Steam GeneratorIn response to the SG tube rupture accident at Mihama 2,

all the SG tubes were replaced with corrosion-resistant material tubes.Takahama 1: FY ‘95-’96, Takahama 2: FY ‘93-’94

Upper Head of RPV It was replaced as the preventive

maintenance against SCC at the upper head nozzle.Takahama 1: FY ‘95-’96Takahama 2: FY ‘96-’97

Refueling water storage tankIt was replaced as the long term maintenance

measure against chlorine type SCC caused by sea salt particles.

Takahama 1: FY ‘04Takahama 2: FY ‘03

CondenserThe tubes were replaced with corrosion resistant titanium tubes to prevent possible sea water leak.


Feed water pump

High pressure feed water heaterThe tubes were replaced with the stainless steel tubes to

improve water quality in the SG. Takahama 1: FY ‘02, Takahama 2: FY ‘00/’03

Low pressure turbineIt was replaced as the preventive maintenance

against SCC at the rotor.Takahama 1: FY ‘92-’94 Takahama 2: FY ‘93-’95

Generator(replacement of stator coil)

The stator coil was replaced as the preventive maintenance against possible degraded insulation.


Low pressure feed water heaterThe tubes were replaced with the stainless steel tubes to improve water quality in the SG.

Takahama 1: FY ‘02/’04Takahama 2: FY ‘03

Heavy Component Replacements in Takahama 1 & 2

KEPCO 13

Upper core

internals

Lower core

internals

・The whole core internals are replaced.

Major ImprovementsMajor Improvements

� Structural change of baffle・ Adoption of square type baffle, longer baffle former bolts, and bolts

with the under head shape modified to reduce stress, and

introduction of bolt cooling holes to lower temperatures, in order to

improve resistance to irradiation assisted SCC.

� Structural change of upper core internals・ To streamline the structure, the upper core support plate is replaced

with the steel circular plate attached to the cylindrical shell,

as adopted by the latest plant.

� Structural change of thermal shielding material・ To streamline the structure, the cylindrical type material is

replaced with the separate type, as adopted by the latest plant.

� Structural change of the radial support・ Adoption of a larger radial support improve the seismic resistance.

Replacement of Core Internals at Mihama 3

before CIR after CIR

KEPCO14

Existing main control panel Digital main control panel

New operating console

Main control panels are replaced with the state-of-the-art digital type

to improve maintainability.

Large display

Replacement of Main Control Panelsin Takahama 1, 2 and Mihama 3

KEPCO 15

Analog Digital

PWR Alliance Agreement (Oct. 19, 2016)

Western Japan 5-company Alliance

(Hokuriku, Kansai, Chugoku, Shikoku & Kyushu)

� Cooperation in the event of a nuclear disaster

� Cooperation in implementing decommissioning

measures, etc.

Mutual Cooperation between

Tokyo Electric Power HD

and Tohoku Electric Power

� Agreement on the Cooperation in

the event of a nuclear disaster

Mutual Technical Cooperation Agreement

(Hokkaido, Kansai, Shikoku, Kyushu)

� Information sharing on Voluntary

Safety Enhancement

� Cooperation to develop new

technologies for next generation light

water reactors and others

Cooperation Agreements for Nuclear Emergencies and

Continuous Improvement of Nuclear Safety Efforts

16

Nuclear EmergencySupport Center

Mutual Cooperation between Chubu, Tokyo and Hokuriku

Mutual Cooperation between Hokkaido and Tohoku

on April 22 and August 5, 2016

Code on Implementation and Review ofNuclear Power Plant Ageing Management Program

English version is

available

Atomic Energy Society of Japan (AESJ) has established the “Code on Implementation

and Review of Nuclear Power Plant Ageing Management Programs” (AESJ-SC-P005:

2008) in 2008 and continuously updated every year.

17

Major input to IAEA

IGALL knowledge-base

Proposal for

Updates

Updating Knowledge-base for Ageing Management in Japan

Operators

of NPPs

(Utilities)

Expert Meeting

from All the

Utilities (JANSI)

Academic

Society

(AESJ)

Regulator

(NRA)

Maintenance

ProgramAgeing Mechanism

Management Charts

Summary Sheets of

Ageing Mechanisms

Endorsement of

the AESJ Code

for Regulatory

Activities

Details of Inspection

and Maintenance Plan

and Activities

Additional Information

including consumables

Operational Experience

AMTE Report

Expert Meeting

Subcommittee for

Plant Life

Management

Evaluation of

Maintenance

Effectiveness Participation

Research for Ageing Management

AMTE : Ageing Management Technical Evaluation before 30 years for Continued Operation

JANSI : Japan Nuclear Safety Institute, AESJ : Atomic Energy Society of Japan

Regulatory Review

18

19

0

200

400

600

800

1000

1200

1400

1600

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010


Decommissioning BWR

1F-1

1F-2 1F-3 1F-51F-4

1F-6


H : Hamaoka

M : MihamaGCR ATR

H-1

H-2

Tsuruga-1

M-1

M-2

Shimane-1

Genkai-1 Ikata-1



Ele

ctri

cal

Ou

tpu

t (M

We

)

Decommissioning PWR

19


Takahama-3,4

Roadmap for Decommissioning of Fukushima Daiichi

20

Estimation of Fuel Debris Distribution in Units 1, 2 and 3

T. Fukuda, NDF (Nuclear Damage Compensation & Decommissioning Facilitation Corporation), presented at ICAPP2017 20

Strategy for Risk Reduction in Fukushima Daiichi

21T. Fukuda, NDF (Nuclear Damage Compensation & Decommissioning Facilitation Corporation), presented at ICAPP2017

Technical Requirements for Fuel Debris Retrieval

in Fukushima Daiichi

• Safety during Fuel Debris Retrieval Work– Establishment of Containment Function

– Maintenance of Cooling Function

– Criticality Control

– Structural Integrity of PCV and R/B

– Dose Reduction during Operation

– Work Safety

• Fuel Debris Retrieval Method– Development of Equipments/Devices

– Establishment of Access Route

– Establishment of Retrieval Systems and their Space

22T. Fukuda, NDF (Nuclear Damage Compensation & Decommissioning Facilitation Corporation), presented at ICAPP2017

23

0

200

400

600

800

1000

1200

1400

1600

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010


Decommissioning BWR

1F-1

1F-2 1F-3 1F-51F-4

1F-6


H : Hamaoka

M : MihamaGCR ATR

H-1

H-2

Tsuruga-1

M-1

M-2

Shimane-1

Genkai-1 Ikata-1



Ele

ctri

cal

Ou

tpu

t (M

We

)

Decommissioning PWR

23


Takahama-3,4

Sampling of RPV Materials and Concrete Structure

from the Decommissioning Reactors

計算精度の検証用

ストリーミング等

の影響確認用

中性子束が小さい

箇所の計算精度を

確認する箇所

コアボーリングで

サンプリング

(深さ

1ｍ程度

)

911

28

4

12

3

56

7

8

16

17

1012

13

1415

18

1920

22

2 3

25 24

27 26

31

30

29

33 32

34

3635

37

39

38

44

45

4849

5153

50

52

5455

56

57

58

21

21

21

For confirming calculation

accuracy


accuracy


accuracy at locations with small

neutron flux

Sampling with core boring

(about 1m in depth)

Instrumentation nozzle

Nut

Vent

RPV top lid

Stud

Guide rod

Flange

Fuel exchanger bellows

Steam dryer

Steam separator

Feedwater inlet nozzle

CRD water return nozzle

Core spray

Shroud lower bracket

PLR water outlet nozzle

CRD guide tube

CRD penetration

Reactor internal structure schematic diagram

Core instrumentation

penetration

RPV support skirt

Support leg

Core pressure differential detector and standby liquid

injection nozzle

Support ring plate

Jet pump instrumentation nozzle

PLR water inlet nozzle

Heat insulator support

Jet pump liner

Core shroud

Shroud head

Heat insulator supportCore spray nozzle

Stabilizer bracket

Steam dryer skirt


Steam outlet nozzle

Leakage detection tap

Modification approval

Oct 22, 1971


Vent


Target for IAEA CRP

Target-1(RPV)

Target-2(Concrete)

Target for IAEA CRP

24

Hamaoka Unit 1

Through Wall Distribution of RPV Embrittlement

Cladding

Distribution of initial T41J

Fast Neutron Fluence

Charpy shift, ΔT41J

due to irradiation

Distribution of T41J

after the irradiation

Base Metal

RPV beltline

Curve not incorporated

initial T41J distribution

(Current Surveillance)Curve with initial

distribution incorporated

Location in thickness

direction of RPV

AESJ 2017 fall meeting (C000596) September 13th, 201725

26

Operation Periods

Comprehensive Soundness Evaluation Methodon Compressive Strength of Concrete

(A-1) Core Sampling

(A-2) Nondestructive Testing

Str

en

gth

Ra

tio

(B)Analysis Results

Data from Aged Structures by Core Sampling and NDT

Cement Hydration Strength of

Concrete

Analysis Conditions of Reactor Building• Material Properties (cement, aggregates etc. )• Mix Proportion, Dimensions of Members• Operation History (temp., humidity, flux, dose rates

Strength of Cement

Paste

Data from Lab Tests

30ys 38ys10ys

(A) Data Collection from Core Sampling and NDT (C) Validation of Analysis Approach

� Core Sampling� Nondestructive Testing� Numerical Analysis Approach

� Assessment of Concrete StrengthStrength Evaluated >= Fc

(D) Comprehensive Soundness Evaluation

Aging Variation of Compressive Strength

Strength ofConcrete during

Operation

(B) Numerical Analysis Approach

Effects of Operation History

Chubu Electric Power Co., Inc. All rights reserved26

Integrity Evaluation of Concrete Structures

Material Basis Evaluation(Strength)

System Member Basis Evaluation (Stress)

Structure Basis Evaluation(Dynamic Properties)

Integrity Evaluation of Concrete Structures

Earthquake

Drying

ShrinkageDecreasing

Trend

Na

tura

l Fre

qu

en

cy

Time

Review of Materials

Properties

Evaluation of Seismic Integrity

of Structures

Microtremor Observation

Forced Vibration test

Core

Sample

Schmidt

Hammer

Strength Evaluation

(Core, NDE, etc.)

Measured>Design

Yes

No

Evaluation of Actual

Load Bearing Capacity

Evaluated>Design

Yes

No

Upgrade

Repair

Seismicity OK?

Yes

No

Upgrade

Repair

Ultra Sonic

Wave

Strength Distributions of

Member Sections

Design

Strength

Axial Forces

Shear Forces

Moments

“IAEA New Coordinated Research Project”, ORNL Meeting ( July 30, 2013) , Osamu Kontani, Kajima Corporation, 27

R&D Strategic Roadmap

for Reactor Safety Technology and Human Resource

[Long-term Objectives of the R&D Roadmap

Safety Foundation

Imp

rov

em

en

t o

f

Ris

k M

an

ag

em

en

t

Ca

pa

bil

ity

Lessons Learnt from the Fukushima Accident,

Current Technology and Human Resources

Continuous

improvement

and progress

A B C D E

Latest Knowledge

and New Findings

in Other Countries

and Related Fields

Nuclear power plants are continuously utilized

as important energy resource to fulfill 3Es,

ensuring safety with the trust from the people

Co

nti

nu

ou

s

En

ha

nce

me

nt

of

Sa

fety

Fo

un

da

tio

n

Tru

st f

rom

th

e S

oci

ety

an

d C

oe

xis

ten

ce

Inte

rna

tio

na

l

Co

op

era

tio

n &

Co

ntr

ibu

tio

n

Tech

nic

al

an

d S

oci

al

Ap

pro

ach

to

wa

rd

Tre

atm

en

t a

nd

Dis

po

sal

of

Ra

dio

act

ive

Wa

ste

s

Sharing and

expansion of

safety foundation

Energy security

Economic efficiency

Environment

3E

28

R&D Strategic Roadmap

for Reactor Safety Technology and Human Resource

Advisory Committee for

Natural Resources and Energy

AESJ’s Special Committee on

Nuclear Safety Research Roadmap

WG on Voluntary Improvement of Safety,

Technology and Human Resource

• IndustriesThe Federation of Electric Power Companies of Japan

Plant Manufacturers

• AcademiaUniversities, JAEA

• Government as observerAgency for Natural Resource and Energy in METI

• Nuclear

Regulation

Authority

(NRA)

Science Council of

Japan

Architectural

Institute of Japan

Japan Association for

Earthquake Engineering

IAEA

OECD/NEA

Organization in

Other countries

Nuclear Standards

Committee of JEA

The Public

Safety Technology and

Human Resource Roadmap

International Community

Nuclear Energy Subcommittee

METI

AESJ : Atomic Energy Society of Japan

Original Plan of

the Roadmap

Request to draft

the Roadmap

Basic Energy Plan in Japan

Positioning of Nuclear Power in Energy Policy

29

Su

b-C

om

mit

tee

Maintenance and

Plant Life Management

Review countermeasures against facility ageing based on

operational experiences and plant maintenance as well as the

challenges related to safe operation.

Safety Improvement

through DesignReview the challenges related to safety improvement through

design activities for fuels, materials, thermal hydraulics, etc.

Accident

ManagementReview the challenges related to accident management.

Earthquake Resistance

and External Events

Review the challenges related to long-term durability of

buildings and structures with taking into account external

events such as earthquakes tsunamis and external events.

Decommissioning (*)Review the challenges related to the processes of safe

decommissioning of the existing reactors and handling of large

wastes, etc.

Nuclear SecurityReview the challenges related to nuclear non-proliferation and

nuclear security as nuclear energy is widely used in

international community.

Sub-Committees in AESJ’s Special Committee on

Nuclear Safety Research Roadmap

* Technology Development related to Decommissioning of TEPCO’s Fukushima Daiichi

NPS is not included in this Roadmap. 30

Milestones in the R&D Strategic Roadmap

for Reactor Technology and Human Resources

(Medium term)

Stage 2(Medium term)

Stage 3(Long Term)

(Short term)

Stage 1(Short term)

2050 1. Innovative Technology to Reduce Risks of Nuclear Power Plant System

associated with Radiation Exposure and Release of Radioactivity

2. Innovative Technology to Reduce the Volume and Toxicity of

Radioactive Waste

3. Global Sharing Latest Knowledge and Technology on Nuclear Safety

2030

2020

1. Nuclear Power as Stable Energy Source with Cost Competitiveness

through Continuous and Risk Reduction of and Trust from the People

2. Advanced Plant Design Technology and Management for Further

Safety Improvement

3. Establishment of International Framework to Cooperation to Share

Human Resources and Technology

1. Voluntary Efforts of Operators with Prime Responsibility to Nuclear Safety and

Dialogue with all the Stakeholders

2. Effective Decision Making to Reduce Risk by both Regulator and Operators

3. Systematic and Harmonized Approach for Disaster Prevention in Japan where

Natural Disasters may induce Large Contribution of Risk

4. Sharing Lessons Learnt from the Fukushima Accident in addition to contribute

Technology Transfer and Knowledgebase for Nuclear Safety 31

Risk

ide

ntifica

tion

Ma

na

ge

me

nt

Human Resource Develop-

ment

Short-Term (S) Medium-Term (M) Long-Term (L)

Asse

ssme

nt o

f

Ex

tern

al E

ve

nt R

iskP

rev

en

tion

of A

ccide

nt P

rog

ressio

n

Comprehensive risk identification and assessment methodology for external events (SI02,SI03,SI13)

Development of systematic earthquake risk assessment framework including ground motion, tsunami, fault displacement and slope failure (SI02,SI14,SI15)

Application of countermeasures against severe accident for existing plant to advanced power plant design (MIII11,MIII12, MIV02)

Development of monitoring & observation framework for natural hazards (SI16)

Application of advanced analysis codes and evaluation tools for risk reduction of existing power plant (including large-scale disaster) (MI01, MIV01)

Development of concept of nuclear

power plant system with enhanced

accident tolerance (LI06, LI08,LII06,

LIII01)

Development of nuclear reactor instrumentation ability under severe accident conditions (SI04,SV01,SII02)

Countermeasures for severe accident (application of risk assessment, mobile equipment, training, etc.) (SI01,SI05, SII01, SIII02, SIV08, SV03)

Development of advanced drill for nuclear accident & disaster (SII01)

Development of advanced analysis codes and evaluation tools for severe accident (SI06,SIV06)

Development of advanced nuclear reactor instrumentation system under any conditions including severe accident conditions (MIII07,MIV03)

Review and reconstruction of organizational structure to cope with critical accident condition (MII03)

Updating and enhancement of monitoring & observation framework for natural

hazards

Continued efforts on research and development of risk assessment framework for rare

natural events for uncertainty reduction of predicted risk (including unidentified events)

(SI02,MI02,LI07)

Building Disaster Resilient Society

Org

an

izat

-ion

etc.

Leadership Education and Human Resource

Development for Accident Management (SII01)

Development of human resources to lead a cross-organizational role for accident and disaster management (MI03)

Development of human resources to fulfill an international role in the area of accident and disaster management (LI08)

Increase of the Human Resources who can apply Scientific Knowledge such as Natural Hazard to Nuclear safety (SII12)

Development and Continuous Attraction of Human Resources who conduct rare event researches on various large scale disasters and also have a motivation to make a contribution for Nuclear Safety (MI02,LI07)

・・・・・・・・・

Examples of the R&D Roadmap : External Risk Assessment and Severe Accident Management

32

• Change in regulatory requirements to extend the reactor operation beyond 40 years is strict enough to make decisions to shutdown some reactors before 40 years of operation.

• Additional inspection and replacement of important components are currently performed for continuous operation.

• Utilization of materials and components from decommissioning reactors in Japan is one of the major topics for international research collaboration.

• Decommissioning activities in Fukushima Daiichi site include many challenging issues on materials and their systems for many years.

• Knowledge management for all the aspects of nuclear technology can be effectively performed through the construction of Strategic Research Roadmap which includes human capacity building after the Fukushima Accident.

• Knowledge management and knowledge transfer for safety of huge complicated systems like nuclear power plants require additional basis for knowledge-base such as “Resilience”.

Summary

33

Thank you very much for your attention.

We are ready to host next PLiM conference in Japan !

See you again in PLiM 2022.

Additional Slides

35

Resilience of Complex Systems

ANL/DIS-12-1 Resilience: Theory and Applications (Jan. 2012)

Relationship between Components of Resilience and Resilience-enhancing Measures

Crisis

Fu

nct

ion

ali

ty

Time

New Equilibrium

Recovery

Response

Preparedness

Mitigation

36

Resilience and Safety for Knowledge Management

SafetyAccident and

Incidents

ResilienceEveryday Actions and Outcomes –

Risks as well as Opportunities

Erik Hollnagel, “Safety-I and Safety-II” p. 148 (2014, ASHGATE Publishing)

Safety-II

Safety-I

37

Change in Safety Requirements

38

• Regulatory limit,

acceptance criteria,

margin changes:

� Decrease in the previously

proven design safety margin

� Revalidation of original design

basis (e.g., external events)

� Additional research for

justification/confirmation

38Arif Nesimi Kılıç (IAEA, Feb, 2017)

Change in DBE Spectrum

39

Design Basis

Events

Severe Accidents

Beyond Design

Basis Events

Design Basis

Events

Severe Accidents

Beyond Design

Basis Events

� New design basis or

margin for external events

� Updated PSAs

� Regulation of SAM

� “Not beyond” design basis

definition


Additional / Reclassified Equipments

40

• Classification/Qualification and

Maintenance of SSCs:

�New design basis for external events

�SBO equipment

�Requirements for PAM

�SFP cooling/inventory equipment,

instrumentation

�Portable/stored equipment

�Permanent structures


Cost and Schedule

• Initially, ~ € 200M / NPP unit

attributed to the measures considered

upon Fukushima accident.

– Those measures include additional tanks,

pumps, diesel generators, safety and non-

safety equipment upgrades, hydrogen re-

combiners, and emergency support

centres/teams, etc.

– They do not really include permanent

design changes (new BUUHS etc.)


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