Aging Management and PLEX in Swiss Nuclear Power Plants

Swiss Utility Working Group

Aging Management and PLEX in Swiss NuclearPower Plants and Prioritisation of Safety Class 2 & 3

Components

AuthorsReinhard Fuchs, NPP LeibstadtJan Stejskal, NPP Muhleberg

GSKL-presentation lAEA-Training-course transparency 1

i


Contents

• Introduction of the Swiss Utilities

• General background

• Swiss Utility Working Group (GSKL)

• Status of Work:

>k Electrical Engineering

>!< Civil structures

>!< Mechanical Engineering

• Prioritisation Method

• Preview

• Conclusions


Swiss Utility Working Group.

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General Background

• Operating lifetime not restricted by time-limited licenses

• December 1991: The Swiss Federal Nuclear SafetyInspectorate (HSK) requested a ageing managementprogramme

• Joint approach of all Swiss Utilities

• 1999: SC1 systems reviewed

• Oldest plants 30 years of operation

• HSK: no technical reason against PLEX for 10 or 20 yearsour goal



GSKL goals

It has to be shown, that at any time operating the plant, thesafety margins will be untouched.

Aging management in accordance with the working groupprogramme shall provide satisfactory proof that for allsafety relevant components all known aging mechanismswill be taken into account in maintenance and qualityassurance, and that measures will be taken for anyomissions revealed.



GSKL „Ageing Management"-group

• Programme for Reviewing and Optimising AgingManagement Measures

• Catalogue of ageing mechanism (KATAM)

• Guidelines for preparing component "Steckbrief"-files

• Specimen "Steckbrief'-files for selected components

• Define responsibilities for the interfaces between thedisciplines


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J Swiss Utility Working Group

GSKL „Ageing Management"-group

• For all systems reviewed a special file, the "Steckbrief" wascreated (contains all important ageing data's)

• Three subgroups were formed for the ageing of electricaland mechanical components as well as civil structures

• AMP shall provide technical basis for:

optimising maintenance programme

improving reliability of components

>\< reduce costs

One important element of AMP is condition monitoring



Status Electrical Components

• Large numbers of electrical components

• Component groups formed (currently 30 groups) likecables, transmitters, motors,...

• The "Steckbrief" for each Component is broken into threeparts:

>\< Ageing mechanisms applicable to component group

* Potential diagnostic methods

>\< Plant specific review of the components in this group, including the

specialities and the experience from the maintenance programmes

part 1 & 2 are generic and done by the GSKL, part 3 by each utility



Status Electrical Components

• For all 30 groups part 1 & 2 are finished

• The specialists in the plants are currently working on part 3of these documents

• The experience so far shows, that the biggest part of theAMP is part of the preventive maintenance measures

• The group is currently focussing on three items:

>\< Maintenance rules

>l< Evaluation of the restlife of cables

>[<• Aging of polymers



Status Electrical ComponentsComponent Groups List Electrical ComponentsA General

The definitions correspond to R23 (HSK)Status: „Steckbrief in edition P (with edition number)

„Steckbrief" finished E (with date)

Date: 23.03.99

finished:in edition:

272

page 1 of 2*) Plant:

В = Beznau

G = GosgenL = LeibstadtM = Muhleberg

В List

1

1.1

1.1.1

1.1.2

1.1.3

1.1.4

1.1.5

1.1.6

1.1.7

1.1.8

1.1.9

1.1.10

1.21.2.1

1.2.2

1.2.3

1.2.4

1.2.5

Componentry, Instruments ; Status N f

S K L

Electromechanical and electrotechnical

Rotatinq electric machines

Motor drives for valves

Transformer, converter

Power circuit breaker

Electromechanical relay

Solenoid valves

Floatinq battery

Contactor & thermal overload protection

Hj-rekombiner

H2-ignition device

Electronic

Rectifier & inverter

Functional units (amplifier, logical units,

limiters)

Pressure-transmitters

Radiation monitors

Manometric switches

P 9 / E 14.12.94

P 14 E 15.09.94

P 50 E 03.12.96

P 49 E 03.12.96

P 4 E 21.02.95

P 5 E 28.04.95

P 4 8 / E 11.09.95

P 4 1 /E 13.05.97

P 7 4 / E 24.03,98

P 107/

P 46 E 13.05.97

P 4 5 E 26.11.97

P 6 / E 21.10.94

P 4 4 / E 03.12.96

P 108/

L 001

В 003

MOOS

L005

M001

В 002

G005

В 005

G 006

L 004

L003

M004

В 001

В 007

M 006

Rev.actual

0

1

0

0

0

0

0

0

0

0

0

0

0

0

0

used forpart 3Plant')

В

B/L

B/L

B/G

B/L/G

B/

Revised

Date name

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th

BP

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Sent to HSK (part 1 & 2) j

Rev.

0

1

0

0

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Iplant

В

B/L

B/L

G

B/UG

DatumI

Dec. 95

Apr. 99

Dec. 97

Sep. 98

Dec. 95/96

GSKL-presentation lAEA-Tratning-course transparency 11

J Swiss Utility Working Group

Status Civil Structures

Guide manual:

>\< Provides general procedure for condition assessment

* Supplies the KATAM, inspection methods and classifying

conditions

• Inspection programme:

>\< Baseline or principle inspections on the outside and inside

Intermediate inspections

Special inspections


No measuresnecessary untilfollowing inspection

Required ConditionCharacteristics:- influence- Possible Damage- Resistance

Evaluation of Results / Damage

no unclear

Actual ConditionFindings:- investigations- Observations- Test Resuits

Difference is relevant for

Consequences

further Investigationsand / or specialexaminations



Status Civil StructuresGuide Manual forstructure-specificAMP-documentation(Steckbrief)

Procedures for reviewapproval, revision

Specimen forStructure-specificAMP-documentation(Steckbrief)

Structural materials

Interfaces tomechanical

— and electrical systems

Degradationmechanisms

Inspection methods

Conditionclassification criteria

PartiDocumentation of specific data:structure and environment

Part 2Specific degradation mechanisms

Part3Inspection plan

Visual InspectionsNon destructive inspections on site

- carbonation- concrete strength- coverage of steel bars- anchorage elements

Laboratory tests

- Inspections- Assessment- Prognosis


Swiss Utility. Working /Group'


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0.8

0.7

0.6

0.5

0.4

0.3

0.2

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—Example of_ .Owner- defined

intervention Limit

-Defined Condition Class

Safety Function Limit

Structural Degradationwith AM

Structural Degradationwithout AM

0% 100%

Engineered Life Cycle

GSKL-presentation IAEA-Train ing-course transparency 15



Plant

Beznau

Units 1 and II

Miihleberg

Gosgen

Leibstadt

Structures with AMP-documents

(Steckbriefe)

- Reactor buildings

- All safety related structures of

auxiliary buildings

Completed main (basic) inspections for condition

assessment

- Reactor building

inner and outer surface of shield building

basemat

internal structures

- Reactor building

all concrete structures

Ventilation stack

- Reactor building

all concrete structures

- Reactor building

inner surface of shield building

basemat



Status Mechanical Components

• All NPP's in Switzerland started with safety class 1 (SC1)related systems

• Assessments for the majority of the systems SC1 are doneand sent to the HSK (Swiss Nuclear Authority) for approval

• „Steckbriefe" = summary file with all important data'srelated to ageing of one system in concentrated form

• Basic documentation, contains additional information's forthe „Steckbrief"

-> High manpower to assess a system




• Example for RPV from Muhleberg NPP

>\< complex component

% many parts

% many materials involved

% varying mechanical and thermal loads

% radiological exposures

# component history, transients

% experiences from other plants



Status Mechanical ComponentsSystem

STECKBRIEFE:

Steamgenerator

Pressurizer relief / degasrfying

Pressurizer

Steamsystem: Steckbrief /basic documetation

Main Coolant Pipes

Main Coolant Pumps

Reactor Pressure Vessel

RPV-lnternals

Feedwatersystem: Steckbrief /basic documetation

Surge Line & DH-Spriihleitung

Recircsystem: basic documetation

Recirc Line Steckbrief /basic documetation

Recirc Pumps Steckbrief /basic documetation

Recirc Valves Steckbrief /basic documetation

Recirc Supports Steckbrief /basic documetation

Steelcontainment

Core-Spray

KKB

SK

1,21,3

1

2, UK

1

1

1

2,4

2, UK

1••••I 2

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KKB1

Report-Nr.

AM-M-1001.6

AM-M-1001.8

AM-M-1001.7

AM-M-1001.1

AM-M-1001.5

AM-M-1001.3

AM-M-1001.4

AM-M-1001.2

•1

KKB2

Report-Nr.

-

AM-M-2001.8

AM-M-2001.7

AM-M-2001.1

AM-M-2001.5

AM-M-2001.3

AM-M-2001.4

AM-M-2001.2

Hi

KKG

SK

1,2

1

1

2, К

1

1

1

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Report-Nr.

AQP-M-006

AUP-M-004

AUPM-001

AUPM-002

AUP-M-005

AUP-M-003

KKL

SK

1,2

•1

2

1,2

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1

1

1

1

2

1,2

Report-Nr.

•H

BET/97/032BET/97/005

ШШШ••1BET/98/0163SA-025.028

BET/98/014BET/98/015

BET/97/129BET/97/078

шшшштBET/96/092

BET/96/098BET/96/093

BET/96/124BET/96/119

BET/96/224BET/96/222

BET/96/225BET/96/223

BET/99/001BET/99/002

KKM

SK

1

Report-Nr.

I3SA-024.225 1ALT-NT-02-MS

3SA-024.188ALT-NT-02-RDB

NEDC-32777ALT-NT-02-INT

3SA-024.224ALT-NT-02-FW

штшшшшщ1 I3SA-O24.207 I

ALT-NT-02-RC•••

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3SA-024.201ALT-NT-16-CONT

3SA-024.226ALT-NT-14-CS




Result of all ageing mechanisms considered:

# intercrystalline corrosion cracking

% stress corrosion cracking

^ fatigue corrosion

# fatigue caused by service transients

% neutron embrittlement

Results documented in "Steckbrief"

• Assessment shows, that the RPV is in a condition toperform its safety function for more than 40 years




• After finishing work on SC1 we have to consider the workson SC2&3

• It is planned to reduce the efforts for these systems, but:

# Higher number of systems with more components in SK 2/3

# For same level of details as for SC1 more work for the assessmentwould be required

• For a reduction we need to find a valid section method,which will be approved by our authority



Prioritisation Method

• Identify all safety significant components

• Get approval by the authority

• Get considerable reduction of manpower

• Use existing data's

• Easy to use




• Use PSA data's to identify the most safety significantcomponents

• Get input from system engineers

• Get input from radiation engineers

• Get input from operation engineers

• Look at the main function of the system

• Finally a walkdown will be performed




• Performed several technical meetings with the HSK

• Made ranking's for pumps, valves, HX, fans andsuperchargers with PSA:

FV > 1 E-3 high importanceFV < 1 E-3 & RAW > 2 medium importanceFV < 1 E-3 & RAW < 2 no importance

The components ranked in the red groups are implementedin the AMPThe ones in the green group are not




• Lists with all components for each SC2 & 3 system

• P&ID's

• Get the inputs from the engineers

• Mark all identified components

• Put it in a network (including all the pipes necessary to fulfilits function)

• Look at the offgoing pipes (10 % of the main pipe)

• All components (inclusive pipes) will be put in the AMP

• Reduction in the range of 80% with a pilot project


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Preview

• Additionally we plan to make another generic documents:

# Identify all materials used

^ Identify all operational conditions

-^Limited number of materials and operational conditions

% make assessments for all materials under all conditions anddocument it in a generic "Steckbrief

• On basis of this generic "Steckbrief' we have only to addspecific informations of components with potential ageingmechanisms on any relevant part (maintenanceexperience,..)



Conclusions

• The main work spent was on the assessments of thesystems, procedures for the implementation in themaintenance programmes necessary

• The Swiss AMP is basic for a PLEX

• All assessments so far have shown good conditions of theSwiss plants



Conclusions

• Swiss utilities discuss to operate the plants longer than 40years

• The current license situation in Switzerland gives us achance to succeed

• The Swiss authority has also given us statements that themain reason for a plant license is to fulfil the safetyrequirements

• PLEX is a considerable option (deregulation, reduction ofcosts)

• The Swiss utilities want to go for PLEX


Documents

Aging Management and PLEX in Swiss Nuclear Power Plants