COMMISSION BRIEFING SLIDES/EXHIBITS

BRIEFING ON PLANT AGING

AND MATERIALS DEGRADATION

NOVEMBER 8, 2004
NO&

-

Management Of

Materials Issues -

Chris Crane

President & Chief Nuclear

Officer, Exelon Nuclear

r'1EI

Materials Initiative

• Coordinates over $59.5M in

industry sponsored materials'

research & development

* Prioritization, management

and resolution of current and

future issues

* Accountability to assure

plant safety'and reliability

ME I

2
I

Management of

Materials Issues

• Background

• Industry Initiative

* Strategic Plan

• Deliverables

• Accomplishments

. Expectations

• Regulatory Process

IJ1

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

N1E:l

4 &
Backround

- Self-Assessment

. Identify barriers or gaps in

current materials programs

. Integrate industry programs

. SG Management (SGMP)'

. PWR Materials Reliability (MRP)

. BWR Vessel & Internals (BWR VIP)

* Fuel Reliability Program'(FRP)

. Chemistry, Corrosion and NDE

. NSSS Owners Groups E 1

......

Background

* Self-Assessment -Conclusions

. Limited coordination of industry efforts

on materials issues

Limited ability to enforce implementation

of industry guidance

. No verification of implementation

. Inadequate participation and support of

Issue Programs (IP)

NSIAC Initiative warranted

6
I I

Background

X 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

NE:I

7

Materials Initiative

* The objective is to assure safe,

reliable and efficient operation

of U.S. nuclear power plants in

the management of materials

issues.

* Each licensee will endorse,

support and meet the intent of

NEI 03-08, Guideline for the

Management of Materials

Issues. This initiative was

effective January 2, 2004. rJE I

x8
Materials Initiative

Purpose is to provide

. Consistent management process

. Prioritization of materials issues

. Proactive, integrated and

coordinated approaches

. Oversight of implementation

.%~

* . .

1. 111111-11 M

Materials Initiative

* Required actions

. Commitment of Executive

leadership and technical

personnel

. Commitment of funds for

materials issues "'within scope

. Commitment to implement

applicable guidance'

documents

10 .
I

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

E I ,,

NEI 03-08 Guideline

• Establishes two standing

committees

. Executive Oversight

. Technical Advisory

X Establishes policy

• Defines roles,

responsibilities and

expectations

• Provides for an integrated

approach rsIEI
ffnm BONN

Policy CommitmentPolicy Statement

*... the industry will ensure that its management of

materials degradation and aging is forward-looking and

coordinated to the maximum extent practical.

Additionally, the industry will continue to rapidly identify,

react and effectively respond to emerging issues. The

associated work will be managed to emphasize safety and

operational risk significance as the first priority,

appropriately balancing long term aging management and

cost as additional considerations. To that end, as issues

are identified and as work is planned, the groups involved

in funding, managing and providing program oversight will

ensure that the safety and operational risk significance

of each issue is fully established prior to final

disposition." "'E I

13 &1:

Materials Issue Programs Governed by the Initiative

* EPRI

. BWRVIP

. MRP

. SGMP

. Fuel Reliability Program (as impacted

by materials management strategies)

. Corrosion Research

. Chemistry Control

. NDE

14 &JE I

14
I

Materials issue Programs Governed by the Initiative

NSSS Owners Group

Subcommittees

. Materials

. Chemistry

. RPV

. NDE

. Steam Generators

Strategic Plan

* Comprehensive, integrated view of

materials issues

• Framework for planning,

coordinating and directing efforts

* Contains elements for an effective

management program

M E:I

I .
Strategic Plan

* Defines high priority materials

issues and short and long term

technical gaps-

* Used as industry guidance for

prioritizing materials issues

• Revision 0 Issued in March

* Revision I planned for. Early 2005

Degradation'Matrix and Issue

Management Table

ISEI

17 &

I

DEGRADATION MATRIX

* Lists all materials within scope

of the Materials Initiative

* Identifies potential degradation

mechanisms for applicable

materials

* Information obtained from

materials experts, laboratory

R&D, and operating experience

, , , ,H _ ' ' '' 'r JE I

18 L«
Issue Management Tables

• Addresses significance of

material degradation on

applicable materials

. Defines where materials are used

and consequences of failure

X Identifies existing programs/guidance available for

effective management

Assessment, inspection/evaluation, mitigation, repair/replacement

19EI

Deliverables - Implementation Protocol

• General guidance for

implementation of IP work products

• Mandatory, Needed & Good

Practice implementation categories defined

. Deviations from Mandatory &

Needed action will be tracked in

Corrective Action Program

i Executive concurrence required for . Mandatory & Needed elements

. Deviations from Mandatory and NeedeN E I

20 &
Deliverables - Emergent Issue Protocol

Oversight and Coordination

. MTAG phone call when emergent

issue occurs

. Lead and support roles defined and

communicated

. IP will lead technical resolution and

NRC interface strategy

Keep MTAG informed of status and

NRC interactions

. MTAG I MEOG support if needed

21 1

111 -1-11 1111M 11111 1

Deliverables

. SG Management

License Change Package

. MRP Inspection and Evaluation

Guidelines

* RPV head and bottom mounted

instrument nozzles

. Primary system butt welds

• WOG

* Pressurizer heater sleeves

* Boric Acid Corrosion Control Guidelines

22
I

Deliverables

n BWR VIP

. Steam Dryers

n Fuel Reliability

* AOA Guideline Revision I

a Performance Metrics

* Overall coordination with

ASME

M E: I

23 b

Proposed Performance

Metrics

• Unexpected materials related NRC

generic correspondence

• New materials degradation operating

experience

• Lost capacity or unplanned/extended

outages due to materials issues

• INPO materials program related AFIs

X Corrective action program effectiveness

• Issue Program products related to

Strategic Plan technical gaps r E I

24
Materials Initiative

Funding

20 projects approved for $9.2 million

. 7 NDE projects for $3M

. 5 MRP projects for $2.4M

* 3 BWRVI P projects for $1 M

* 2 Corrosion Research projects for $600K

. 1 Fuels Reliability project for $1.2M

* I SGMP project for $61 5K

. 1 Chemistry, Control project for $350K

25

-I -I I 1-1 II NBMNM

Accomplishments

* NEI Initiative

NEI 03-08

• Strategic Plan

. Protocols

. Funded projects

26
p

Future Activities

• Complete the Issue Management

Tables and revision I of the Strategic

Plan

. Develop industry performance metrics

and self assessment guidance

• Monthly MTAG phone calls - materials

issue oversight & coordination

* Quarterly meetings with the NRC

. Complete self assessment and report

results

FE I

27 b

Expectations for Industry . Adopt a proactive approach to

materials issues . Communication of OE with IP I NEI

• Develop an integrated materials plan that reflects industry's Strategic Plan

priorities

• Be prepared to fully implement applicable IP recommendations

• Support materials IPs and their need

for technical and leadership personnel

* Support funding to address materials

issues

• Self assessment of activities fI E: I

28 &
MMMEMEN

Changes to Expect

* Industry guidance from IPs will

have mandatory and needed actions

. Improved communications on

materials issues and related

interactions with the NRC

* Improved integration/coordination

among IPs

. Improved industry performance

relative to materials degradation

. Successful transition to a proactive

approach for materials issues

29

---- -9

I ___

Regulatory Process

* Implementation of mandatory

and needed actions that fall

within the scope of 10 CFR 50

* Primary system components

. Subject to NRC inspection

* Performance-based approach

* Areas of Concern

* Unnecessary duplication

. Diversion of resources

30
I

Conclusion

n Actions Taken by Industry

. Proactive, integrated and

coordinated

. Focus to assure plant safety

and reliability

.. Continuous improvement and

feedback

E:l

31 &$

Mimi=

Additional Background

r P1l

32 faz
ACRONYMS

AFI - Area For Improvement

AOA - Axial Offset Anomaly

ASME - American Society of Mechanical Engineers

BWR - Boiling Water Reactor

BWR VIP - Boiling Water Reactor Vessel & Internals

Program

CFR - Code of Federal Regulations

EPRI - Electric Power Research Institute

FRP - Fuel Reliability Program

INPO - Institute of Nuclear Power Operations

IP- Issue Program

NDE - Nondestructive Examination a Er 1

33 -

amn9whou

ACRONYMS

NEI - Nuclear Energy Institute

NSIAC - Nuclear Strategic Issues Advisory Committee

NSSS - Nuclear Steam Supply System

MEOG - Materials Executive Oversight Group

MRP - Materials Reliability Program

MTAG - Materials Technical Advisory Group

OE - Operating Experience

R&D - Research and Development

RPV - Reactor Pressure Vessel

SG - Steam Generator

SGMP - Steam Generator Management Program

WOG - Westinghouse Owners Group rN E I

34
materuaus executive Oversight Group (MEOG)

* Chris Crane

(Chairman) - Exelon

* Jim Levine (ViceChairman) - APS

* Garry Randolph -

AmerenUE

* Joe Sheppard - STP

* Bryce Shriver - PPL

* Art Stall - FPL

* Gary Taylor - Entergy

* David Mauldin - APS

* Rodney Webring -

Energy Northwest

* Jim Klapproth - GE

* Nick Liparulo -

West.

* Gary Mignogna -

AREVA

* Mark Reddemann -

INPO

* Dave Modeen -

EPRI

* Alex Marion - NEI

N E: I

35

Materials Technical

Advisory Group (MTAG)

* Chairman - David Mauldin - APS

* Vice Chairman - Bill Eaton -

Entergy

* BWRVIP/BWROG - Robin Dyle -

SNOC

* MRP - Mike Robinson - Duke

* SGMP - Forrest Hundley - SNOC

* FRP - Charles Turk - Entergy

* WOG/CEOG - Greg Gerzen -

Exelon

* BWOG - Dave Whitaker - Duke

* EPRI NDE - Mike Turnbow - TVA

* EPRI Chem - John Wilson -

Exelon

* EPRI Corrosion - Craig

Harrington - TXU

* At Large Members

. Joe DonahueProgress Energy

* Dennis Weakland

- FENOC

* Bob Hardies -

Constellation

* Ralph Phelps -

OPPO

* MTAG Support

* EPRI - Chuck

Welty

* INPO - Steve

Johnson

* NEI - Jim Riley

rJE1

36
Z

Degradation Matrix

a

37 JEI1

Issue Management Table

a Draft example of -- ;

component evaluation

ME: I

38 &
Materials Degradation Matrix

Level I

Level 2

Reduction in Toughness

PWR RiT

Component

Material

'Subdivision-k

SCC

SCC

Corrosion/Wear

C&W

Fatigue

Fat. -

Aging Irradiation

PWR

Pressurizer

(Including

Shell, Surge

and Spray

Nozzles, Heater

Sleeves and

Sheaths,

Instrument

Penetrations)

C&LAS

C&LAS

Welds

Wrought

Ss

SS Welds &

Clad

I

Wst2 Pit Wear FAC HC LC/Th Env Th Emb VS

N

e,.17

SR I Th. Fl

eO16

Y N N Y N Y Y Y N/A N/A N/A N/A N/A

eO04 eO05 eO06 e007 eO08

Y N N Y N Y Y Y N/A N/A N/A N/A N/A

eO04 e005 e006 e007 eO08

N N N N N Y Y N N/A N/A N/A N/A N/A

eO14 e015

N N N N 4 IeO15 e N N/A / /AN/A

N N N N Y Y Y N N/A N/A N/A N/A N/A

eO14 e014 eO15

N N N N N Y Y N N/A N/A N/A N/A N/A

eO14 eO15

Wrought N I'N'' N

Ni Alloys

Ni-base

Welds &

Clad

N

t02

Level 3

eO30 Corrosion-assisted fatigue is a known phenomenon on secondary side (e.g., in the vicinity of girth welds in steam generator shells

and in the region of feedwater nozzles) and is not like environmental fatigue described in other areas of this DM. Environmental

fatigue research relevant to this specific phenomenon is not ongoing within MRP Fatigue ITG, and is a potential gap.

1 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved.

co"
Materials Degradation Matrix

4.3 Fatigue Degradation Mechanisms and Mitigation Options

Fatigue is the structural deterioration that can occur as the result of repeated stress/strain cycles

caused by fluctuating loads or temperatures. After repeated cyclic loading, if sufficient localized

micro-structural damage has been accumulated, crack initiation can occur at the most highly

affected locations. Subsequent cyclic loading and/or thermal stress can cause crack growth.

A brief description of the relevant fatigue-related degradation mechanisms is provided below.

43.1 Hfigh-Cycle Fatigue

The most 'classical' fatigue-related degradation mechanism is high-cycle (HC) fatigue. HC

fatigue involves a high number of cycles at a relatively low stress amplitude (typically below the

material's yield strength but above the fatigue endurance limit of the material). High cycle

fatigue may be:

I

3.2 Material Compositions and Properties

A large variety of welding materials and welding processes are used to join carbon and low-alloy

steels, and it is not practical to show typical material compositions and material specifications.

Section NB-243 1.1 of Section 111, Division I of the ASME Code requires that weld materials

have tensile strength, ductility and impact properties that match those of either of the base materials being welded, as demonstrated by tests using the selected weld material and the same or

similar base materials. Section NB-2432.2 of Section ItI, Division I of the ASME Code requires

that the chemical composition of the welding material be in accordance with an appropriate

ASME Code welding specification (in Section It.C of the Code), but leaves the choice of the

specific material up to the manufacturer.

The most common weld processes used to join carbon steel and LAS parts include submerged

arc welding, shielded metal arc welding (SMAW), and gas tungsten arc welding (OTAW). Postweld heat treatment is generally required per ASME Code rules after welding of the carbon and

lowtalloy steels used for reactor coolant system service. Copyright© 2004 Elec tric Power Research Institute, Inc. All rights reserved. I-0=IaI

Ceo-z-
4.3 Fatigue Degradation Mechanisms and Mitigation Options

Fatigue is the structural deterioration that can occur as the result of repeated stress/strain cycles

caused by fluctuating loads or temperatures. After repeated cyclic loading, if sufficient localized

micro-structural damage has been accumulated, crack initiation can occur at the most highly

affected locations. Subsequent cyclic loading and/or thermal stress can cause crack growth.

A brief description of the relevant fatigue-related degradation mechanisms is provided below.

4.3.1 High-Cycle Fatigue

The most 'classical' fatigue-related degradation mechanism is high-cycle (I IC) fatigue. HC

fatigue involves a high number of cycles at a relatively low stress amplitude (typically below the

material's yield strength but above the fatigue endurance limit of the material). Ihigh cycle

fatigue may be:

3.2 Material Compositions and Properties

A large variety of welding materials and welding processes are used to join carbon and low-alloy

steels, and it is not practical to show typical material compositions and material specifications.

Section NB-243 1.1 of Section 111, Division I of the ASME Code requires that weld materials

have tensile strength, ductility and impact properties that match those of either of the base materials being welded, as demonstrated by tests using the selected weld material and the same or

similar base materials. Section NB-2432.2 of Section III, Division I of the ASME Code requires

that the chemical composition of the welding material be in accordance with an appropriate

ASME Code welding specification (in Section II.C of the Code), but leaves the choice of the

specific material up to the manufacturer.

The most common weld processes used to join carbon steel and LAS parts include submerged

arc welding, shielded metal are welding (SMAW), and gas tungsten arc welding (GTAW). Postweld heat treatment is generally required per ASME Code rules after welding of the carbon and

low-alloy steels used for reactor coolant system service.

3 Copyright @ 2004 Electric Power Research Institute. Inc. All rights reserved. I'I ZI
Draft BWR Issue Management Table

Equipment Material Failure Consequences Mitigation Repair/ I & E Gaps Priority & Responsible

Mechanism of Failure Replace Guidance Basis Program(s)

BWR SS (Ic and SCC, Leakage, Yes, chemical and Yes, replace pipe Yes, Low - BWRVIP,

Recirculati hc), fatigue forced outage stress or weld overlay BWRVIP. solution WCC

on piping Inconel improvement 75 available

o pipin n g w elds_ _ _ _ _ _ __ _ _ __ _ _ _ _

BWR Cs/las, ss IGSCC, LOCA - loss Yes - HWC, Yes - nozzle Yes - covers Low - BWRVIP

Vessel clad, welds IASCC, of asset NMCA repair embrittleme solution

TGSCC, nt and weld available

FIV, Th & degradation

Env Fatigue,

Emb, Tb

aging,

Fluence

BWR Ss, cass, cs, IASCC, Core Yes - some, work Yes - shroud and Yes High - BWRVIP,

Internals welds, Inc TGSCC, configuration needed top-guide, costly (interim) - existing and WCC, FRP, FIV, Wear, _ work needed 13 BWRVIP potential Corrosion

EF, Emb. I&E unresolved Research

Fluence - Guidelines - issues

R&D work needed

needed

Core Stainless IGSCC, This is a. Hydrogen Water The repairs to BWRVIP Fracture High BWRVIP

Shroud Steel IASCC, function of Chemistry at date have been has - toughness priority with the Reduction in location. moderate levels mechanical' developed a decrease items for the Assessment

Toughness Vertical weld can protect the clamps that series of with shroud still Committee

flaws have shroud at lower replace some or inspection increasing exist. leading

minor levels and some all of the guides that fluence Initially was

significance benefit is available circumferential have been and there the number

unless the at higher levels in welds, This is combined is limited one priority.

intersecting some plants. accomplished by into one data to With

circumferential When augmented. developing high overall - help the programs in

weld is flawed with Noble compressive document industry place for

through-wall. Metals, more loads on the (BWRVIP- understan inspection,

Very flaw shroud protect is shroud which 76). This d long the needs for

.1.

I
tolerant for

circumferential

flaws.

Significance of

circumferential

weld flaws is

based on

location of the

weld.

Limiting

accident

scenario is

main steam

line break

coupled with

an earth quake.

Even then,

shroud

circumferential

welds were

shown to

perform -

adequately

with 90%

through wall

flaw, 3600 in

circumference.

It is worth

noting that

should a flaw

develop for the

full

circumference,

the shroud

would lift

enough to

"burp" itself

possible due to the

need for les

hydrogen due the

to the catalyst

effect of the noble

metals. Plantspecific

assessments are

needed to

determine the

exact level of

protection. Other

methods of

protection are

being

investigated/consi

dered such as

water jet peening

etc.

negates the need

for the

circumferential

welds. This

provides

significant

redundancy since

no

circumferential

welds to date

have come near a

360 degree

through-wall

flaw. Repair by

welding is very

limited in

prospect due to

difficulty in

welding on

highly irradiated

stainless steels.

document

includes '

inspection

criteria for

circumferent

ial and

vertical

welds, and

support ring

welds, The

criteria also

address both

repaired and

unrepaired

shrouds

including

repair

hardware.

The

evaluation

criteria exist

for all

locations

and is based

on long

standing

ASME

criteria

including

safety

factors.

Evaluation

methods

also' account

for the

changes in

crack

term

issues.

Work is

underway

to develop

additional

data prior

to the:

shrouds

reaching

fluence

levels of

concern.

Similarly,

work is

underway

to

properly

understan

d and

characteri

-ze crack

growth

behavior

in highly

irradiated

stainless

steels.

the shroud

are reduced.

I

2
and provide growth rate

and provide

operators with

an indication

of a problem

and allow safe

shutdown.

growth rate

and fracture

toughness 

a

irradiation

damage

increases.

The methods

also allow

for crack

growth to be

adjusted

based on

water

chemistry,

residual

stresses,

changing K

values, etc. .1. & S .1. _ l 

l

.

3
SPA REG(J4

MIATERIALS

DEGRADATION

ISSUES

Jim Dyer, Director NRR

Dr. Carl Paperiello, Director RES

November 8, 2004
Acronyms

* ASME:

* BWR:

* CCDF:

* IASCC:

* IGSCC:

* ISI:

* NRR:

* PIRT:

* PWR:

* PWSCC:

* RCS:

* RES:

* RPV:

American Society of Mechanical Engineers

Boiling-water reactor

Conditional core damage frequency

Irradiation-assisted stress-corrosion cracking

Intergranular stress-corrosion cracking

Inservice inspection

Office of Nuclear Reactor Regulation

Phenomena identification and ranking table

Pressurized-water reactor

Primary water stress-corrosion cracking

Reactor coolant system

Office of Nuclear Regulatory Research

Reactor pressure vessel

2
Reg u-atory Overview

* Regulatory framework

* Historical issues with materials

degradation

* Current challenges

* Future goals

3
Regulatory Framework

* Regulations

-ASME Code requirements for

design and inspection

* Technical Specifications

- Leakage monitoring

* Bulletins and Orders - short term,

emergent issues

4
Regulatory Framework

(continued)

* Integration of Research for

degradation management

programs

* Industry actions and initiatives

5
Regulatory Framework

(continued)

* Regulatory Oversight

-Baseline ISI

- Temporary Instructions

- Follow up interactions with

licensees

- Reactor Oversight Process

indicators and findings

6
Historical Issues With

Matereals

* Radiation

embrittlement of

RPVs

* IGSCC in BWR

piping

* BWR internals

cracking

Degradation

* PWSCC in PWRs

* Boric acid

corrosion

* IASCC in PWRs

* Vibratory fatigue

* Thermal fatigue

* Erosion/corrosion

* Steam generator

tube degradation

7
Current Challenges

* PWSCC of penetration nozzles in

reactor and other vessels, nozzle

welds

-Addressed through Bulletins and

Order

* PWSCC in dissimilar metal butt

welds of RCS piping

- Regulatory action being

considered

8
Current Challenges

(continued)

* Extended power uprate adverse

flow effects

- Steam dryer cracking

- Feedwater probe failure

- Staff monitoring industry

actions

9
Current Challenges

(continued)

* Steam generator degradation

-Active NRC oversight

- Implementing new regulatory

framework through technical

specifications

10
Future Goals

* Return to more stable regulation

* Increase reliance on industry

* Proactive oversight

* Operating experience monitoring

* Independent NRC research

11
Proactive Materials

Degradation Assessment

* Research input into regulatory

activities

* Approach

* Short-term program

* Longer term program

* Implementation schedule

* Utilization of results

12
Research Input Into

Regulatory Activities

* Environmentally assisted cracking

- BWR pipe cracking

- Internals cracking

* Steam generator integrity

* Nondestructive Examination

* Pressure vessel integrity

13
Approach

* Some of the materials

degradation in nuclear power

plant components experienced in

the past has surprised both NRC

and industry

* NRC & industry pursuing proactive

approach to materials

degradation

14
Approach

(Continued)

* Identify components of interest to

ensure reliability

* Coordinate research for effective

implementation of proactive

materials degradation management

15
Approach

(Continued)

* Activities to identify components

- Information on degradation that

has been experienced - shortterm results

- Phenomena identification and

ranking table (PIRT) for potential

future degradation - longer term

results

16
Short-term Program

* Identified components that have

already experienced degradation

* Evaluating inspection and leak

monitoring techniques and

requirements

* Provide input to conditional core

damage frequency (CCDF)

* Probabilities of failure for

probabilistic risk assessments

17
Longer Term Program

* PIRT process

- Expert elicitation

* International in scope

* Bounded - important plant systems

being addressed

18
Longer Term Program

(Continued)

* Background information provided to

expert panel members - Component's environment and

operational experience

* Experts identify and rate

degradation mechanisms, assess

knowledge levels, and provide

bases for decisions

19
GROUP 1: RCS Cold Leg Piping

(Covers worksheets RCS-CL - I thru 28)

Q Thff"Awan dabtb

\N.10

~REAUBOR =OLANTfr FPUWM!

vEASItL

® Larg8 BoTe Brmch nozz!c (~:3')

Q Small Bore Brwnch nozulei (43')

Q"~ cacurnator A5-dog.A'ngle nozzle (10')

®~ 3' x i142' reducer aftac1.ed to brancft nozzles

20
Implementation Schedule

* First two PIRT meetings on PWR

reactor coolant system and

emergency core cooling system completed

-Potential future degradation being identified

* Six more meetings to complete PWR and BWR evaluations

* PWR report - June 2005

* BWR report - December 2005

21
Utilization of Results

* Lists of components susceptible to

future degradation, bases for calls,

and knowledge levels

* Input to cooperative integrated

research programs

* Technical basis for effective

proactive materials degradation

management by NRC and industry

22