Fourth International Conference on Nuclear Power Plant Life Management, Lyon 23–27 October 2017

Naam:

Functie:

Datum: datum maand jaartal

Volledige naam

Functietitel

From LTO assessment to

living ageing management

André de Jong

Rob Bollen

NPP Borssele

The Netherlands

2

Topics

Introduction of NPP Borssele

Changing LTO Horizon

LTO requirements overview

License Renewal Process

• LTO assessment project

From a static assessment to living ageing management

3

NPP Borssele

Siemens/KWU 2-loop

PWR

515 MWe (485 MWe net)

Original design lifetime:

40 years

Long Term Operation: 60

years

Every 10 years a PSR

3707 GWh production

(2012)

4

PWRs in Europe (connected before 1980)

Facility Process Mwe net Current status Start Year Owner Location

Beznau-1 PWR 365 Operating 1969 Nordostschweizerische Kraftwerke (NOK)

Switzerland

Beznau-2 PWR 365 Operating 1971 Nordostschweizerische Kraftwerke (NOK)

Switzerland

Borssele PWR 452 Operating 1973 N.V. Elektriciteits-Produktiemaatschappij Zuid-Nederland (EPZ)

Netherlands

Biblis-A PWR 1167 Shut Down 1975 RWE Power AG Germany

Doel-1 PWR 392 Operating 1975 Indivision Doel (EBES, INTERCOM, UNERG)

Belgium

Doel-2 PWR 392 Operating 1975 Indivision Doel (EBES, INTERCOM, UNERG)

Belgium

Ringhals-2 PWR 870 Operating 1975 Swedish State Power Board Sweden

Tihange-1 PWR 962 Operating 1975 Electrabel Belgium

Neckarwestheim-1 PWR 785 Shut Down 1976 EnBW Kraftwerk AG Germany

Biblis-B PWR 1240 Shut Down 1977 RWE Power AG Germany

Fessenheim-1 PWR 880 Operating 1977 Electricite de France (EdF) France

Fessenheim-2 PWR 880 Operating 1978 Electricite de France (EdF) France

Bugey-2 PWR 910 Operating 1979 Electricite de France (EdF) France

Bugey-3 PWR 910 Operating 1979 Electricite de France (EdF) France

Bugey-4 PWR 880 Operating 1979 Electricite de France (EdF) France

Goesgen PWR 970 Operating 1979 Kernkraftwerk Switzerland

Unterweser PWR 1345 Shut Down 1979 EON Kernkraft GmbH Germany

5

Changing LTO horizon

• 1973: NPP Borssele in commercial operation; no end date

• 1994: political agreement on closing NPP Borssele in 2003

• 1994-2006: political discussions and lawsuits on closing date:

NPP Borssele has no end of license date!

• 2004: feasibility study on LTO (60 years): positive business case

• Covenant on June 16th 2006:

• Long Term Operation to 2034

• Borssele should be amongst the

Top 25% safest Western LWRs

• Sept. 2013 application for License Renewal

• March 2013: LTO-license signed, fought against by NGOs but

High Court rejected the objections: February 2014 irreversible

license!

6

Changing LTO horizon

7

Requirements for safe LTO

License Renewal Process: change of Safety Report (FSAR) to

comprise operation until 2034 based on:

• LTO assessment according to IAEA guidelines (SRS57)

• Assessment on organizational/human issues

The plant is among the 25% safest Western LWRs:

• To be judged periodically by the Borssele Benchmark

Committee

Not specifically related to LTO but necessary:

Further improving nuclear safety with the fourth PSR (2010-213)

Implementing measures based on stress test (Fukushima)

RPV inspection to rule out ‘hydrogen flakes’

8

License Renewal Process

Regulatory framework:

• Nuclear Energy Act (Kernenergie wet)

• Nuclear Safety Rules (NVR), based on IAEA Safety Standard Series

• Original NVRs provide no guidance on LTO

• PSR every 10 years

• Unlimited license (but agreement to shutdown before 2034)

• Safety Report: design life 40 years (Time Limited Ageing Analyses)

• Basis by IAEA LTO guidelines

• IAEA Safety Report No. 57 (Safe Long Term Operation of Nuclear Power Plants)

• IAEA Safety Guide No. NS-G-2.12 (Ageing Management for Nuclear Power Plants)

• KFD-review

• IAEA SALTO peer reviews

• GRS: review of all LTO reports

9

License Renewal Process

(continued)

Additional Requirements:

Dutch regulator KFD:

• IAEA SALTO peer review 2009:

- Verification of preconditions

- Active Components

• Include IAEA PSR Safety Factor 10

(Organisation and Administration) and PSR

Safety Factor 12 (Human Factor) in LTO

license change application

10

LTO assessment: the principle

• Structures and components of an NPP are subjected to

material degradation

• Task of the LTO assessment is to show that the NPP

safely can and will be operated despite (potential)

physical ageing of structures and components important

for safety

11

LTO assessment project (technical

part)

LTO “bewijsvoering”

KCB

Feasibility (3.1)

Verification of

preconditions (3.2)

Scoping (4.1)

Screening (4.2)

Check of existing

plant programmes

TLAAs (6)

RPV

EQDBA

LBB

Fatigue

Mechanical

Electrical

Documentation of basis

for LTO

IAEA Safety report Nr 57

Safe Long Term Operation of

Nuclear Power Plants

IAEA NS-G-2.12 (ch 6)

Ageing Management for Nuclear

Power Plants

Mechanical A

(barrier concept)Electrical Civil / structuralMechanical B

Implementation of plant

commitments for LTO

ActiveAMR (5)

Passive

Regulatory

framework

IAEA

guidelines

Phase prior to LTO

assessment

(SR57, fig1)

Phase LTO

assessment

(SR57, fig1)

Phase LTO

approval &

implementation

(SR57, fig1)

Civil / structural

VROM

Regulatory

Oversight

12

LTO assessment project (technical part)

• KCB project LTO “bewijsvoering” based on IAEA Safety Report 57:

• Feasibility and verification of preconditions;

• Scoping, screening and Ageing Management Reviews;

• Revalidation of the following TLAAs:

• Reactor Pressure Vessel (RPV);

• Fatigue;

• Leak Before Break;

• Qualification of Design Base Accident resistant electrical Equipment.

• Assessment of active components;

• Documentation for LTO basis;

• Regulatory oversight and the KCB implementation of plant commitments.

• The outcome of the project LTO “bewijsvoering” was submitted to the authority

for a license change procedure for long term operation of KCB until 2034.

LTO “bewijsvoering”

KCB

Feasibility (3.1)

Verification of

preconditions (3.2)

Scoping (4.1)

Screening (4.2)

Check of existing

plant programmes

TLAAs (6)

RPV

EQDBA

LBB

Fatigue

Mechanical

Electrical

Documentation of basis

for LTO

IAEA Safety report Nr 57

Safe Long Term Operation of

Nuclear Power Plants

IAEA NS-G-2.12 (ch 6)

Ageing Management for Nuclear

Power Plants

Mechanical A

(barrier concept)Electrical Civil / structuralMechanical B

Implementation of plant

commitments for LTO

ActiveAMR (5)

Passive

Regulatory

framework

IAEA

guidelines

Phase prior to LTO

assessment

(SR57, fig1)

Phase LTO

assessment

(SR57, fig1)

Phase LTO

approval &

implementation

(SR57, fig1)

Non technical requirements

IAEA Draft Safety Guide No. 426

Periodic Safety Review of Nuclear

Power Plants

SF 10 & 12

Civil / structural

VROM

Regulatory

Oversight

13

Overall schedule LTO-project

limited scope full scope follow-up

2014 201520132008 2009 2010 2011 2012

Scoping

SALTO peer reviews

Screening

Ageing Management Review of passive Structures & Components

Revalidation of Ageing design:Time Limited Ageing Analyses; Environmental Qualification

Formal License approval proces

License appl.

regulator review (GRS)

Verif. plant programmes

Active Components Assessment

Licensesigned

Additional measures and verification

Regulatory review of implementation license requirements

14

‘Going towards coordinated

Ageing Mgt’

Assessment on Ageing Management

System taking into account several

performed reviews on Ageing Management

(self, regulator and peers)

Basis: NVR NS-G-2.12 IAEA Safety

Guide ‘Ageing Management of Nuclear

Power Plants’ 2009

Currently three pillars on Ageing

Management:

1.Maintenance, Surveillance and Inspection

Process

2.Ageing Management Experience Feedback

Procedure

3.Ageing Management Reviews

LTO “bewijsvoering”

KCB

Feasibility (3.1)

Verification of

preconditions (3.2)

Scoping (4.1)

Screening (4.2)

Check of existing

plant programmes

TLAAs (6)

RPV

EQDBA

LBB

Fatigue

Mechanical

Electrical

Documentation of basis

for LTO

IAEA Safety report Nr 57

Safe Long Term Operation of

Nuclear Power Plants

IAEA NS-G-2.12 (ch 6)

Ageing Management for Nuclear

Power Plants

Mechanical A

(barrier concept)Electrical Civil / structuralMechanical B

Implementation of plant

commitments for LTO

ActiveAMR (5)

Passive

Regulatory

framework

IAEA

guidelines

Phase prior to LTO

assessment

(SR57, fig1)

Phase LTO

assessment

(SR57, fig1)

Phase LTO

approval &

implementation

(SR57, fig1)

Non technical requirements

IAEA Draft Safety Guide No. 426

Periodic Safety Review of Nuclear

Power Plants

SF 10 & 12

Civil / structural

VROM

Regulatory

Oversight

15

From a static LTO assessment to

living ageing management

• Ageing Management has

proven to be adequate

and largely consistent

with NVR NS-G-2.12 and

up-to-date

• Need for improvement on

coordination and

traceability

• Decision to implement a

specific SSC oriented

ageing management

process strongly based

on the LTO AMR

• Consistent with BBC

requirement

16

SSC based AM Strategy

• Ageing degradation mechanisms for SSC are determined

• Shows on a high level how these

ageing degradation mechanisms

are to be managed at KCB

• Based on AMR project documents

• Provides the basis for the low-

level plant programs (AMPs)

• IGALL based document format

• KCB-specific implementation

• Provides link to (existing) activities

• Scope verification by mechanism matrix in

AM strategy documents

• Enables traceability and auditability

17

Example Steam Generator (PU-N12-50-302)

Steam generators

1. Introduction

• Scope

2. Component description

• Primary/secondary design description

• Design analyses

• Materials

• Operating conditions, media, water chemistry

3. Operational experience

Internal, including modifications

External

Relevant IAEA - IGALL documents

4. Ageing management of applicable mechanisms

5. Roles and responsibilities

6. Results matrix

18

Scope Steam generators

Primary side of both steam generators (YB)

• Primary chambers

• Tubesheet

• Division sheet

• Manholes primary side (including nozzle, -

sealing plates and covers)

• Tube bundle

• In- and outlet nozzles (YA)

• Dewatering primary chambers

• Dewatering manhole nozzles

Secondary side of both steam generators(YB)

• Shell

• Downcomer annulus

• Feedwater ringline

• Feedwater nozzle (RL)

• Steam outlet nozzle (RA)

• Nozzles for blowdown line (RY)

• Tube bundle support (straps, camconstruction,

distance strips)

• Manhole secondary side (including nozzle, -sealing

plate and cover)

• Handholes secondary side (including nozzles, -

sealing plates and covers)

• Instrumentation nozzles, level control

• Instrumentation nozzles, temperature control

• Instrumentation lines up until1st isolation valve

• Supports, welded to the outside of the steam

generator

19

Matrix of mechanisms Steam Generator, primary side

Age

ing

me

chan

ism

Bo

ric

Aci

d C

orr

osi

on

(P

U-N

12

-50

-46

1)

Inte

rcry

stal

line

SC

C

(PU

-N1

2-5

0-4

70

)

Pit

tin

g (P

U-N

12

-50

-46

3)

Stre

ss r

ela

xati

on

(P

U-N

12

-50

-44

0)

We

ar/f

rett

ing

(PU

-N1

2-5

0-4

30

)

PW

SCC

(P

U-N

12

-50

-46

2)

Cre

vice

co

rro

sio

n

(PU

-N1

2-5

0-4

63

)

The

rmal

Age

ing

(PU

-N1

2-5

0-4

10

)

Tran

scry

stal

line

SC

C

(PU

-N1

2-5

0-4

75

)

Fati

gue

(P

U-N

12

-50

-45

0)

Component

Outside area steam generator BCD ABC

Primary cambers and nozzles ABC A

Division sheet ABC A

Tube bundle ABC I A

Tube sheet AD FGH

Rolled plugs I

Explosion formed plugs ABC A A

Welded plugs AD

Manhole cover ABC DJ

Nozzle dam bolts ABC A

Dewatering lines ABC ABC A

Closure bolting BCD BC E F

A Water chemistry

B Leakage

walkdowns

C Leak monitoring

D ISI

E Preventive

tensioning

F Fatigue analysis

G Managing

transients

H FAMOS

I Loose Parts

monitoring

J Preventive

replacement

20

Example AMP for FAC (PU-N12-50-460)

Ageing Management Plan: Flow Accelerated Corrosion

Table of Contents

1. Introduction

2. Evaluation and Technical Basis

• Scope of the ageing management programme

• Preventive actions to minimize and control ageing

degradation

• Detection of aging effects

• Monitoring and trending of aging effects

• Mitigating ageing effects

• Acceptance criteria

• Corrective actions

• Operating experience feedback and feedback of

R&D results

• Quality management

3. References

4.Appendices

History of relevant KCB based events

History of pH value

Inspections

21

Continuous improvement

Improved coordination

Ownership

Review by specialist in SC working groups

Interface with existing ageing experience

feedback procedure

Cooperation with integral Equipment Reliability

process

22

Thank you for your attention

N.V. EPZ Zeedijk 32, 4454 PM Borssele Telephone +31 113 - 356000 epz.nl werkenbijepz.nl

EPZ: one GigaWatt of electricity!

23

Scope AMP for FAC

Scope of the AMP is based on expert

knowledge of the FAC mechanism

Scope determined during project with AREVA in 1988

Refined over the years due to operational experience

• E.g. areas with extremely low Oxygen content after Mihama

accident (Japan, 2004)

Scope laid down in FAC AMP

Scope not confined to SSC that are important for

nuclear safety or SSC whose failure may impact SSC

important to safety

- back -

24

Preventive actions

Preventive actions to minimize and control FAC

Ensure that plant is conductive to optimized water chemistry

• E.g. replacement of CuNiFe condensors with Titanium units

Maintain high pH levels, at KCB not below 9,3 since1978

Maintain water chemistry to support Magnetite (Fe3O4) protective

layer (Redox potential)

• Validated by replacement

of RK condensate line

section in 1990

- Back - 9

9.1

9.2

9.3

9.4

9.5

9.6

9.7

9.8

9.9

1073

75

77

79

81

83

85

87

89

91

93

95

97

99

01

03

05

07

09

11

13

pH

Jaar

pH in main condensate system

25

Detection of ageing effects

Main effect of FAC/EC is wall thinning at susceptible areas

• Determine susceptible areas by analysis

• Measure wall thickness by Ultrasonic Testing at representative areas

Visual inspection may also be performed in suitable

systems

• Large bore piping (1000 mm)

• Heat exchangers

Inspection frequency in line with operational experience to

prevent unacceptable extent of wall thinning

• Safety

• Code compliance

- Back -

26

Monitoring and Trending

Currently, monitoring and trending is based on engineering

judgment:

• Evaluation of FAC analysis

• Interpretation of UT test results by expert judgment (RTD and ISI

expert)

• Results show generally stable conditions

Application of COMSY in preparation

• Analysis of areas under suspicion (e.g. feedwater nozzle on SG)

• Verify current analyses

• Trending of inspection results

Pipe sections that are hard to analyse:

• At least a once-off UT inspection to provide insight in actual condition

- Back -

27

Mitigating Ageing Effects

Control of water chemistry:

• pH

• Oxidation / reduction potential

Repair or replacement

• Where possible using less FAC/EC susceptible materials

Investigation of other mitigating measures:

• Increase wall thickness of new components

• Reduce flow velocity by changing pipe configuration

- Back -

28

Acceptance criteria

Currently by conservative engineering judgment

• RTD inspection report

• Visual inspection

Prognosis of remaining number of operating cycles if

inspection results show degradation

Currently in preparation of implementing COMSY

• Conservative estimation of required ISI interval

• Verification of current prognoses

- Back -

29

Corrective Actions

Short term:

• Detailed evaluation

• Repair or replacement

Long term:

• Changes to operational conditions

• Design changes with regard to material selection or geometry

Design changes

• Where feasible, apply materials with higher Cr content

• Pay sufficient attention to downstream components after any design

change

- Back -

30

Operating Experience and

R&D feedback

Ageing related notifications:

• Application of VOB procedure PU-N12-19:

- Operational feedback by WANO, INPO, VGB, AREVA

- Internal experience (SWG – Failure analysis workgroup)

Active contribution to maintaining current with state-of-the-

art developments:

• Participation in relevant forums (VGB AK-KOM for component

integrity, VGB AK-ROHR specialized forum on piping systems)

• Attending applicable conferences by EPZ specialists, e.g. 3-yearly

International Conference on Flow Accelerated Corrosion, France

- Back -

31

Quality Management

EPZ Quality, process and document configuration

management procedures are applicable

The Ageing Management Process PU-N12-50 and its

supporting documents such as the Ageing Management

strategies and Ageing Management Plans form part of

EPZ’s Integral Management System.

Purpose of the EPZ Integral Management System is to

provide support for:

• Obtaining operational targets

• Risk management

• Compliance with legislatory and regulatory requirements

- Back -

32

Inspections

AKS Omschrijving Component deel Aspect Inspectie interval (Jaar)

PMID PMRQ Scope

RA000Z007 LEIDENDE LEIDING Bocht 1 UT-W 12 4882 3 FAC

RA000Z008 LEIDING Bocht 18 UT-W 12 4883 2 FAC

RA000Z011 LEIDING T-stuk 3 UT-W 12 4885 2 FAC

RA000Z020 LEIDENDE LEIDING UT-W 10 4886 1 FAC

RB001Z003 Leiding waterafscheider-herverhitter VT 8 5206 3

RL000B001 VOEDINGSWATERONTGASSER Stomp 20 RP021S009 UT-W 4 5345 1

RL010Z001 T-stuk UT/W Eenmalig 2004 FAC

RL011Z001 LEIDENDE LEIDING T-stuk 3 UT-W 4 5345 3

RL011Z001 LEIDENDE LEIDING T-stuk 9 UT-W 12 5429 2

RL011Z001 LEIDENDE LEIDING Verloop 10 UT-W 12 5429 2

RL011Z003 LEIDING Bocht 3 UT-W 12 5431 2 FAC

RL011Z008 LEIDING T-stuk 2 UT-W 5 5432 1 FAC

RL011Z008 LEIDING Verloop 1 UT-W 5 5432 1 FAC

RL012Z001 LEIDENDE LEIDING Verloop 10 UT-W 12 5478 3

RL012Z009 LEIDENDE LEIDING T-stuk 1 UT-W 5 5482 1

RL013Z007 LEIDENDE LEIDING Verloop 10 UT-W 5 5531 1 FAC

RL023Z009 LEIDING Bocht 4 UT-W 8 5603 1

RL023Z009 LEIDING T-stuk 1 UT-W 8 5603 1

RL031B001 HD VOORVERWARMER Wand t.p.v. RF-stomp UT-W 4 5646 4

RL031B001 HD VOORVERWARMER Wand t.p.v. RP-stomp UT-W 4 5646 4

RL031Z001 T-stuk UT/W Eenmalig 2004 FAC

RL032B001 HD VOORVERWARMER Wand t.p.v. RF stomp UT-W 4 5658 4 FAC

RM020Z001 LEIDENDE LEIDING Reduceer naar RM023Z001 UT-W 6 5965 8 FAC

RM020Z001 LEIDENDE LEIDING T stuk aansluiting RM020Z005 UT-W 6 5965 5 FAC

RM023Z001 LEIDING Bochtstuk na RM020Z001 UT-W 6 5983 1 FAC

RN021Z003 Leiding na meetflens RN021F001 UT/W Eenmalig 2004 FAC

RT000Z002 LEIDENDE LEIDING Verloop 1 UT-W 10 6488 1 FAC

RU000B002 LD-ONTSPANTANK UT-W 10 6550 1 FAC

RY010B002 SPUIKOELER UT-W 8 6621 4 FAC

SD013B003 Standpijp "C" DN 1000 VT 6 6980 1 FAC -Back-

33

Integration in operations

34

Closing the loop

- Back - - End -