~U.S.NRC

United Suics Nuclear Regulatory Commisio~n

Protecting People and the Environment

Commission. Briefing on

Reactor Materials

Islsues0

April 28, 2008
Agend

* Introduction - Jack Grobe, NRR

S"Regulatory ActivitiesMichele Evans, NRR

* Research ActivitiesJennifer Uhle, RES

* Human Capital ResourcesJack Grobe

2
Introduction

* Pressurizer nozzle flaws

* New Code requirements

* Proposed vessel rule

* Extended operation workshop

* Proactive management NUREG

* NDE effectiveness research

3
Upper Head Background

* Oconee - Spring 2001

- Circumferential cracking

* Bulletin 2001-01 -Aug. 2001

* Davis-Besse - Spring 2002

-. Head corrosion

* NRC Order EA-03-009- Feb. 2003

- Revised in February 2004

4
Inspections for PWSCC in

Upper Head Penetrations

* All baseline inspections complE

• NRC Order EA-03-009 Inspectio

-.Susceptibility ranking

- 1 of ~ 1500 Low susceptibility

nozzles identified PWSCC

te

ns

5
Upper Head Replacement

* PWSCC resistant -materials

* Half replaced to date

* Anticipate all High and Moderate

susceptibility plants will replace

heads

6
Longer Term Approach

* ASME Code Case N-729-1

-Replace Order

* 10 CFR 50.55a revision to

include Code Case

- Final Rule- scheduled May 2008

7
PWSCC in Butt Welds

• PWSCC .in dissimilar metal (ODM)

butt welds since ,2000

* MRP-139 DM butt weld inspection

guidelines

* Staff monitoring MRP-139

Temporary Instruction

8
Longer Term Approach

- Staff req uested ASME Code to

develop inspection requirements

- Code case under development

- NRC will incorporate code case

in 10 CFR 50.55a

9
Recent Butt Weld Operating Experience

* Wolf Creek pressurizer welds

-Advanced finite element ...analyses

* PWSCC in two Babcock & Wilcox

plant drop line D! welds

* Retired pressurizer weld

inspection

10
RPV Embrittlement/Aging

* Management of RPV aging is

critical to ensuring plant safety

* Four key NRC rules/regulatory

guides establish regulatory

framework

11
Current Regulatory

Framnwr

*More, than adequate to maintain

nuclear safety

*Excess conservatism may impact

plant. operation and/or plant

operating life

12
Current & Future Actions

* Significant improvement made in

our understanding of RPV integrity

.issues

* Plan to implement improvements

through .ruleemaking

13
Extended Operation

Materials Issues

* NRC/DOE Workshop Feb. 2008

o Aging issues for long-term

operation beyond 60 years

.Industry development needs

* Integrated aging management

research plan

14
Proactive Management of

Materials Degradation

* PMMD allows for action before

degradation is safety significant

* NUREG/CR-6923

" Material susceptibility and

knowledge level

* Comparison to industry results

15
PMMD (continued)

o Review of current research

programs

* Collaborative programs with

industry but maintain

independence

* Enhance coordination

* Prioritize issue resolution

16
PMM.D Imp ementation

S.Database to facilitate updates

• Links to operating experience and

research findings

*Knowledge man agement tool

* International cooperation

17
Non-Destructive

Examination Techniques

. Resolution by prevention or

detection and repair/replacement

* industry initiatives to reduce inservice inspection (ISI) time

* Reliability and effectiveness of

NDE techniques are more .important

18
NDE (continued)

* Weld overlays

* High density polyethylene piping

* Program for inspection of nickelbased alloy components

* NDE and PMMD inform NRC's

review of Life Beyond 60

19
Materials Human

.Resources

* Human Capital

-Hiring/Retention

- Training/Knowledge

Management

-,Technical: Consistency

20
Acronyms

*PWSCC - Primary Water Stress

Corrosion Cracking

* MRP - Materials Reliability

Program

* NDE- Non-destructive

examination

* RPV- Reactor Pressure Vessel

*ASME - American Society of Mechanical Engineers

21
Acronyms

* PMMD- Proactive Management of

Materials Degradation

22
Briefing on Reactor Materials

Issues

Alexander Marion

Executive Director

Nuclear.Energy Institute

April 28, 2008
Industry Panel

n Introductions - Alex Marion, NEI

m Materials initiative - Jeff Gasser, SNC

- Chairman, Materials Executive Oversight

Committee

m Materials issues programs and operating

experience - Joe Hagan, FENOC.

Chairman, EPRI PWR Materials

Management Programs Executive

Committee

/ 2
Materials Issues Introductory

Comments

* Materials issues continue to be among the top

priorities for the nuclear industry

* Materials Initiative approved unanimously by

Chief Nuclear Officers in May 2003

- An NEI Initiative is an industry CNO commitment

to establish and implement a defined policy and

associated actions

- Commits the entire nuclear power industry

* Presenters will cover industry activities and

Utility specific experience

f 3
Materials Initiative

Jeff Gasser

Executive Vice-President and Chief

Nuclear Officer

Southern Company

April 28, 2008

1'
Overview

" Materials Initiative

" Guidance Documents

" Planning for the Future

* Results

" Summary

/ 5
Background

* NEI executive committee resolution in 2002

* Self assessment of materials programs

* Recommendations

- Use NSIAC Initiative to establish policy

- Establish oversight groups

- Enhance INPO role

- Enhance communications

- Provide funding

/f,

6
Materials Initiative

*Provides

- Consistent management process

- Prioritization of materials issues

-Proactive approaches

- Coordinated approaches

- Oversight of implementation

*Objective

-Safe and reliable operation
The Initiative is Working

* Industry Codes and regulatory requirements

provide high assurance of structural integrity

* Industry documents establish inspection

guidance beyond Code and regulatory

requirements

* Expectations communicated and understood

8
Industry Programs Aligned Under the

Materials Initiative

" Materials Reliability Project (MRP)

" PWR Owners Group Materials Subcommittee

(PWROG MSC)

" BWR Vessel Integrity Program (BWRVIP)

" Steam Generator Management Program (SGMP)

" Non-Destructive Examination (NDE)

" Water Chemistry Control

" Primary Systems Corrosion Research

/ 9
Industry Materials Organization

EOG)

orrIssu esogarnsij2

10
Industry Materials Issue Program Scope

Guideline development

-MRP

e PWR reactor vessel and primary system materials

- SGMP

* PWR steam generator tubing and tube inspections

- BWRVIP

* BWR reactor vessel and primary system materials

- PWROG Materials Subcommittee

* PWR primary system materials tactical and

operational issues

11
Industry Materials Issue Program Scope

Support and research

- NDE

* Non-destructive examination equipment and technique

development/demonstration

- Corrosion, Research

" Primary system component corrosion research

" Irradiation effects

- Water Chemistry Controls

9 PWR and BWR chemistry control limits and methods

e Stress corrosion cracking mitigation methods

12
NEI 03-08 Guideline

Applies to all programs involving primary

system materials.

- Defines expectations for management of

materials integrity

- Establishes policy

- Establishes oversight function

.- Defines roles, responsibilities, and

expectations

- Provides for an integrated approach

13
NEI 03-08 Addenda

Establishes standards for implementation

- Materials Management Program Guideline

- Emergent Issues Protocol

- Strategic Plan

- Implementation Protocol

- Performance Metrics

- Self Assessment Protocol

14
Strategic Approach

* Strategic plan defines the key priorities and

objectives

- Defines intermediate and long term strategic issues

- Identifies critical gaps

* Materials Matrix identifies materials

vulnerabilities and level of knowledge

* Materials Issues Management Tables identify

open items and establishes priorities

15
Materials Initiative Results

* Executive level commitment

" Structured assessment guides priorities

" Improved guidance

" Significant advancements in inspection

capability

" INPO review visits

- Primary system integrity

- Steam generator management

- BWR vessel integrity

/ 16
Materials Initiative Results

*$300M spent addressing materials integrity

since 2003

*No challenge to plant safety since the

Materials Initiative adopted

*Aggressive inspections finding problems

before structural integrity limits are

challenged

17
PWR Primary System Piping Inspections

PWR nickel-alloy butt weld inspection program

Spring 2008 - all plants complete overlays of pressurizer dissimilar

metal welds (DMW)

12/31/08 - inspect or mitigate DMW in piping > 4" and <14" in

diameter and exposed to hot leg temperatures

- 12/31/09 - inspect or mitigate DMW in piping > 14" in diameter and

exposed to hot leg temperatures

- 12/31/10

" inspect or mitigate DMW in piping exposed to cold leg

temperatures

" inspect DMW > 2" and < 4" in diameter and exposed to

temperatures equivalent to the hot leg or serve an ECCS function

" inspect DMW > 1" and < 4" in diameter without a requirement for

UT exam

18
Expectations for Industry

" Continue proactive approach

" Implement integrated materials plan reflecting

Strategic Plan priorities

" Implement applicable Issue Program guidance

" Support materials Issue Programs

- Support funding

" Perform periodic self assessments

/19
Summary

*Industry executive commitment to ensure

structural integrity

*Resolving. challenges while maintaining

- Safety

- Reliable operation

* Improving performance

" Sharing operating experience

* Communicating effectively with NRC

20
Materials Issues Programs &

Operating Experience

Joe Hagan

President and CNO

FirstEnergy Nuclear Operating Company

April 28, 2008

L
Overview

" EPRI PMMP

" Materials Issue Programs

* Operating Experience

22
EPRI Materials. Organization

Nuclear Power Sector

Nuclear Power

Council

Other EPRI Issue

Programs:

BWRVIP*

NDE

Water Chemistry

Corrosion Research

*- Separate Executive

Oversight Committee

-1~najgepfi'0htro'gram~

K ~~PMM)

23
Future Priorities

* Planned

- Effect of RCS environment on the performance of

materials

Damage initiation processes and development of

predictive models

Mitigation

- Inspections and Evaluations

- License Renewal beyond 60 years

* Emergent

- New plant materials issues, collaboration with

ANT

- Materials degradation operating experience from

domestic and foreign plants

24
Materials Initiative Expectations for

Operating Experience

* Clear expectations for communicating

operating experience

- NEI 03-08

* Industry protocols in place for responding

to emergent issues

25
Operating Experience

Summary

26
Davis Besse

Decay Heat Nozzle

* FENOC rescheduled Davis Besse's 2008 refueling to

December 2007

Pre-emptive weld overlay project included 16 reinforcement

welds; 14 on Pressurizer system, two on Decay Heat

-During automated weld overlay process on Decay Heat

nozzle, through-wall leakage discovered

- Weld process halted

- Problem Solving/Decision Making (PS/DM) Team formed

* Prompt contact with Nuclear Regulatory Commission

- Consulted with

* Electric Power Research Institute (EPRI)

" Institute of Nuclear Power Operations (INPO) and

" Nuclear Energy Institute (NEI)

27
Davis Besse

Decay Heat Nozzle

*Confirmatory Ultrasonic Testing (UT)

discovers 1.3 Inch axial flaw

-Experts attribute flaw to primary water stress

corrosion cracking

*Resolution plan process a dopted:

-Portion of exposed weld material ground away

-Automated welding proceeded with nine layers of

,overlay weld

-UT exams and Penetrant Testing were

successfully completed to verify weld quality and

ensure structural integrity

28
Davis Besse

Decay Heat Nozzle - Lessons Learned

* Prior review of weld history

* Communications protocol

- Inform all stakeholders promptly

- Material Reliability Project briefing sheet

- EPRI, NEI, INPO involvement upfront

- Direct & repeated dialog with NRC

- Mutual agreement on going-forward plans

* Industry engagement

- EPRI Non-Destructive Examination Center support

29
St. Lucie

Pressurizer Nozzle

* Studying nozzle from pressurizer replaced in 2005

- Industry and NRC collaborative research project

* Performed preliminary NDE to determine value for

further study

- Indications considered potential challenge to

structural integrity basis

* Industry responded to concern

* Advanced ultrasonic NDE verified fabrication

induced defects

- Further verified with traditional radiography

/" 30
St. Lucie

Pressurizer Nozzle - Conclusions

* Two separate approaches - NDE and

analytical

- Finite element analysis method remains valid

- Defects not structurally significant

Same conclusion: no safety concern exists

* Rapid and thorough industry response

considered a strength

31
SAFETY NOZZLE 'A'

Sketch showing nozzle

flaws after encoded UT.

The initial flaw profile

after manual phased

array NDE is shown by

the red line.

LOOKING INTO HEAD

LI 32
Farley Nuclear Plant

" SNC committed to proactively address nickelalloy materials issues

" Replaced steam generators 2000=2001

" Replaced reactor vessel heads 2004-2005

* Capital replacement projects improve plant

safety and reliability before significant problems

can occur

33
Farley Nuclear Plant Chemical

Mitigation

* Both Units have continuously added zinc since 1999

to mitigate PWSCC

Farley Unit I was first commercial PWR to add zinc to

primary side in 1994

Farley 2 was the only one of five plants with material

heat M3935 in reactor vessel head penetrations

that did not experience cracking

- Materials from the Farley 2 and Davis Besse replaced

heads are being tested in an Owners Group program

to demonstrate zinc addition effectiveness in

mitigating PWSCC

/7 34
Farley Nuclear Plant Unit 2 Pressurizer Surge

Nozzle

" April 2007 - First PDI manual UT exam of surge nozzle

identified an axial indication.

" Due to complex geometry phased array UT was used to

size the indication.

" The axial indication was confirmed and a separate

circumferential indication was identified.

* Removal of a boat sample was considered but precluded

by the existence of a thermal sleeve, the location and

shallow depth of the indications.

" ASME Code analysis showed the as-found nozzle was

acceptable through the completed operating cycle.

" Weld overlay of the surge nozzle was performed.

/35
Farley-1 Pressurizer Heater Sleeves

* October 2007 visual inspection identified very small

(pinhead size) white residue at the heater sleeve to

bottom head annulus on two heaters

" -Physical characteristics of the residue were not like a

typical boric acid deposit

- chemistry sample indicated boron and cesium-137

" Heaters were removed, NDE performed to verify no

through wall defects

" New heaters were installed

" Contingency plan developed for future heater exams

1/ 36
Hatch-1

Control Rod Drive Return Line Nozzle

* Performed weld NDE data review as a

result of operating experience

- Resulted in additional weld examination

* Indication on one control rod drive return

line nozzle weld

* Circumferentially oriented defect

* NDE Center confirmed

* Weld repaired with overlay

/~ 37
SNC Lessons Learned

* Pro-active response to operating

experience

* Conservative decision making

* Prompt communications with industry

* Prompt communications with NRC

* Document operating experience

* Follow through with lessons learned

/" 38
Overall. Summary and Conclusions

Industry response to ongoing and

emergent issues is effective

* Conservative decision making evident in

field applications

* Proactive sharing of experience and

lessons learned

* Experience input to industry guidance

documents and program priorities

/" 39
Acronyms

" NEI_- Nuclear Energy Institute

" NSIAC - Nuclear Strategic Issues Advisory

Committee

" RCS-- Reactor Coolant System

" PWR - Pressurized Water Reactor

m BWR - Boiling Water Reactor-

* DMW - Dissimilar Metal Welds

40
Acronyms

" BWRVIP -Boiling Water Reactor Vessel Internals

Project

" MRP - Materials Reliability Project

" NDE - Non-destructive Examination

" SGMP - Steam Generator Management Program

" APWG - Action Plan Working Groups

" ANT - Advanced Nuclear Technology

" UT - Ultrasonic Testing

* PDI - Performance Demonstration Initiative

41
Back-up Slides

9,

42
Background

* NEI Executive Committee

Resolution

- Fully support industrywide effort to

improve management of materials issue-

* Self-Assessment of Materials

Programs

- Driven by recent plant events

- Develop a more proactive process

43
Backround

* Self-Assessment

- Identify barriers or gaps in current

materials programs

- Integrate industry programs

* SG Management (SGMP)

e PWR Materials Reliability (MRP)

* BWR Vessel & Internals (BWR VIP)

* Fuel Reliability Program (FRP)

* Chemistry, Corrosion and NDE

* NSSS Owners Groups

/

44
Background

* Self-Assessment Conclusions

- Limited coordination of industry efforts on

materials issues

- Limited ability to enforce implementation of

industry guidance

- Limited verification of implementation

- Inadequate participation and support of Issue

Programs (IP)

- NSIAC Initiative warranted

45
Background

* Self-Assessment

Recommendations

- Create executive-level and technical

oversight groups

- Establish policy on the management

of materials issues

- Use the NEI Initiative Process

- Expand INPO's role

- Enhance communications

Define regulatory interface

7 46
Materials Initiative

" Approved by NSIAC in May 2003

" Each licensee will meet the intent of

NEI 03-08, Guideline for the

Management of Materials Issues

* Initiative effective January 2, 2004

Includes $12M for 2004-2005 to fund high

priority materials issues in addition to the

$47.5M currently budgeted by Issue

Programs for 2005

,1 47
Materials Executive Oversight Group

(MEOG)

" Jeff Gasser (Chairman)

- Southern Company

" Joe Sheppard - STP

" Chris Crane - Exelon

" Joe Donahue -

Progress Energy

" Mano Nazar - AEP

" Joe Hagan - FENOC

" Mike Robinson - Duke

" Greg Wilks- NEIL

" Jim Klapproth - GE

" Nick LiparuloWest.

" Gary Mignogna -

AREVA

" Rick JacobsINPO

" Dave Modeen -

EPRI

" Alex Marion - NEI

/

1' 48