nei 03-08 overview · 2017-05-22 · nei 03-08, guideline for the management of materials issues...

© 2017 Electric Power Research Institute, Inc. All rights reserved.

Robin DyleEPRI Materials Programs

USNRC Materials Programs Technical Information Exchange Public Meeting

May 23, 2017

NEI 03-08 Overview

2© 2017 Electric Power Research Institute, Inc. All rights reserved.

OverviewPrimary system materials integrity is vital to plant

performance and reliabilityReactor components operate in a harsh environment - high

temperatures, cyclic stress, vibration, intense neutron fields, etc. Numerous materials and alloys exist in a plant’s systems

and the aging of these materials is complex and not always fully understoodRoutine surveillances, ISI, and replacements can mitigate

some of these factors; however, some failures can be expectedChallenge: To find the next material vulnerability and to

address it before any failures occur


Operating Experience through 2002

Reactor Internals components:– Core shrouds– Core spray piping– Jet pump beams– Jet pump inlet piping– Top guides– Steam dryers– BWR fuel support castings– PWR baffle bolts and split pins

Pressure boundary items:– BWR recirculation piping– BWR CRD stub tubes– Pressurizer heater sleeves– Primary system full penetration butt welds– PWR reactor vessel bottom mounted nozzles– PWR CRDM head penetrations


Forcing FunctionBWRs had programs dealing with IGSCC

– Piping covered by GL 88-01 and then BWRVIP-75– Reactor internals managed by BWRVIP program

A series of events in PWRs motivated industry executives to take broad generic action– Indian Point steam generator tube– V.C. Summer dissimilar metal weld leak– Multiple PWR head penetration leaks– Davis-Besse head wastage


Alloy 182/600304, 304L, or 347SS

Recirc. Inlet Safe

End and nozzle welds

Access Hole Cover

Steam Dryer

Recirc. Piping Welds

Jet Pump Riser Brace

Core Shroud Welds

Top Guide

Core Spray Piping

SRM Dry Tubes and

In-core Housing

CRD Stub Tube to

Housing Weld

Shroud-to-Shroud

Support Welds

Jet Pump Beams

Core Spray Safe End

to Nozzle Weld

Butters

Jet Pump Riser

Elbow

BWR Internal Components


PWR PWSCC Potential Impact

*Surge nozzle

-pipe welds

Spray nozzle-pipe weld

*Safety & relief

nozzle-pipe welds

*RV nozzle-pipe

weld

CRDM motor housing

*CRDM nozzles

to RV head welds

*Instrument tubes

Core support

block

Monitor tube

Head vent pipe*Heat transfer tubing

Tubesheet (TS) cladding

Tube-TS cladding weld

*Partition plate & welds

*Bottom channel head

drain tube & welds* Represents locations that have experienced cracking and or leakage at other PWRs are highlighted

in red.


The issues and expectation

What will fail next?When will it fail?Are replacement materials susceptible?

Industry must anticipate and stay ahead of these problems


1st Step - Self-Assessment

In August 2002 NEI Executive Committee directed industry to:– Get in front of material issues– Perform assessment of materials programs to identify strengths,

weaknesses, and make recommendations– ScopePrimary pressure boundary components in BWRs and PWRsMaterial issues related to nuclear fuelsNDE Chemistry/corrosion control programs

A Materials Assessment Working Group (MAWG) was formed with representatives from all industry groups dealing with materials issues


Key Conclusions from MAWG Assessment

Industry lacked a unified strategic focus and directionLimited coordination of industry efforts on materials issues Budget and funding challengesUnable to enforce and to verify implementation of industry

guidance Oversight of industry materials efforts was inconsistent Industry participation in materials issue programs lacking Implementation of materials tools inconsistent

Recommendation: Define an NSIAC Initiative to address materials aging management


What is a NSIAC Initiative?

Formal agreement among the utility Chief Nuclear Officers (CNOs) that form the Nuclear Strategic Issues Advisory Committee (NSIAC) to follow a defined policy

Requires 80% vote of the NSIAC for approval

Binding industry commitment at CNO level for full implementation– Not a formal regulatory commitment

– Provides regulatory credibility

– Deviation process involves an informal regulatory commitment


Materials Initiative Each licensee will endorse, support and meet the intent of

NEI 03-08, Guideline for the Management of Materials Issues– Purpose is to provide for

Consistent management processes

Prioritization of materials issues

Proactive, integrated and coordinated approaches

Objective is to assure safe, reliable and efficient operation of U.S nuclear power plants in the management of materials issues.

Approved by Nuclear Strategic Issues Advisory Committee (NSIAC) in May 2003

Initiative was effective January 2, 2004


Materials Initiative (NEI 03-08) Expectations

The body of materials work conducted across the industry will be forward-looking and coordinated, resulting in fewer unanticipated issues that could consume an inordinate level of resources and divert focus from an orderly approach to managing materials

This initiative will enhance the issue programs’ ability to rapidly identify, react and effectively respond to emerging issues – OE is reported and industry responds

Every utility will fully participate in the implementation of the materials management activities applicable to its plants

INPO verifies implementation - excellence is target

NRC interactions routine and frequent – no surprises


NEI 03-08 – Guideline for the Management of Materials Issues

Documents the Materials InitiativeDefines scope of the InitiativeEstablishes policyIdentifies Issue Programs within scopeDefines roles, and responsibilities

– MTAG and MEOG– Issue Programs (IPs) – Utilities

Current version is Revision 3, effective March, 2017


Materials Initiative

The objective of this Initiative is to assure safe, reliable and efficient operation of the 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 is effective January 2, 2004. The purpose of this Initiative is to:

– provide a consistent management process – provide for prioritization of materials issues – provide for proactive approaches – provide for integrated and coordinated approaches to materials issues

Utility actions required by this Initiative include: – commitment of executive leadership and technical personnel – commitment of funds for materials issues within the scope of this Initiative – commitment to implement applicable guidance documents – provide for oversight of implementation


November 2008

Materials Management Policy

Initiative Policy Statement– “… the industry will ensure that its management of materials

degradation and aging is forward-looking and coordinatedto 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.”


NEI 03-08 Scope and Issue ProgramsScope

– Reactor internals– Primary system pressure boundary components– Related NDE, chemistry and corrosion controls– Other as directed by NSIAC

Issue Programs (IPs)– EPRIBWRVIPMaterials Reliability Project (MRP)Steam Generator Management Program (SGMP) Nondestructive Examination (NDE)Primary Systems Corrosion Research (PSCR)Water Chemistry Control (WCC)

– PWR Owners Group Materials Subcommittee (MSC)


NEI 03-08 Expectations for Owners

Utility responsibilities (shall)

– Maintain a RCS Materials Degradation Management Program

– Implement “Mandatory” and “Needed” IP guidance (see next slide)

– Participate in IPs

– Apply appropriate focus on materials issues

– Communicate materials OE


NEI 03-08 Implementation Requirements

NEI 03-08 guidance is classified as follows:– “Mandatory” - to be implemented at all plants where applicable– “Needed” – to be implemented whenever possible, but

alternative approaches are acceptable– “Good Practice” – implementation is expected to provide

significant operational and reliability benefits, but the extent of use is at the discretion of the individual plant or utility

In practice, “Mandatory” and “Needed” guidance is required unless a formal deviation disposition is processed (similar to a ASME Code Relief Request). The only difference for a deviation from “Mandatory” guidance versus one from “Needed” guidance is that deviating from “Mandatory” guidance requires independent 3rd party approval.


NEI 03-08 Expectations for Issue Programs

Materials IP responsibilities

– Identifying, prioritizing, and resolving issues

– Communicating

– Managing regulatory interface

– Developing guidance

– Reviewing deviations

– Self assessments and performance metrics

– Process for addressing emergent materials issues


Materials Organizational Structure

PMMP Executive Committee (EC)

Nuclear Power Council

Materials & Aging Action Plan Committee (MAPC)

Executive Chair:CNO/VP Level Executive

Technical Chair: VP/Director Level Executive

BWR Vessel Internals Program (BWRVIP)

Materials Reliability Program (MRP)

Steam Generator Mgmt Project (SGMP)

Primary System Corrosion Research

(PSCR)

BWRVIP Executive Committee

NDE Action Plan Committee*

Other APCs not shown

PWR Owners Group Materials Subcommittee (PWROG MSC)**

PMMP (EOC)

Welding & Repair Technology Center

(WRTC)

BWRVIP EOC

Water Chemistry Action Plan Committee

Long Term Operations

*NDE APC coordinates with Materials APC and PWR Owners Group **Materials Subcommittee has a representative on Materials APC


Initiative Accomplishments

Integrated industry strategic plan for materials Achieved a high level of industry integration, coordination, alignment,

and communication on material issues Established a process for prioritizing projects, budgets, and planning Predictable funding for materials R&D Engaged INPO as an active participant Defined expectations and protocols for industry actions upon discovery

of an emergent issue Established consistent process for deviations and communication with

NRC Executive level interactions between industry and senior NRC

management Successful at closing materials issues and gaps Fewer unexpected materials related transients


Latest updates


Background

As a part of the delivering on the nuclear promise initiative, NEI 03-08 issue programs (IPs) have developed a document screening process to be used in conjunction with the topical report review and approval process– Reduces resource expenditures on low value reviews, speeds utility

implementation of new guidance– Not intended to be prescriptive, IPs may choose to use the topical

report review and approval process where warranted, even in cases where the guidance revisions would pass document screening

Analogous to 50.59 process - includes initial “applicability evaluation” and more detailed “screening evaluation”Process is intended to guide NEI 03-08 IPs, does not (and

cannot) replace or supersede plant-specific limitationsContained in Appendix C of NEI 03-08 Rev. 3


Key Elements (1 of 2)

Applicability Evaluation– Intended to be simple to use– Used to determine when further

document screening is applicable– Screening only applicable for

reports containing IP controlled aging management guidance that have been previously approved by NRC safety evaluation

(1c)Prior guidance approved by NRC via SE or is credited to meet a specific IP commitment to NRC?

(1a)Topical report revision / replacement or new topical report contains implementable aging management guidance?

(1d)Does the guidance represent a technical change to NEI 03-08 Mandatory or Needed elements?

(1e)Could implementation of the guidance result in a change to aging management elements other than the inclusion of new elements?

Perform screening evaluation of new / revised aging management guidance.[Go to Fig. 2, box (2a)]

YES

YES

No EPRI IP controlled implementation elements. Screening not applicable.

Document may be generically released by the IP for implementation without NRC approval.

NO

NO

YES

(1b)Implementable aging management guidance elements are applicable to safety-related SSCs or to nonsafety-related SSCs generically subject to aging management for license renewal?

YES

YES

Guidance relevant to asset preservation only and may be generically released for implementation without NRC approval.

NO

NO

NO

“APPLICABILITY EVALUATION” PROCESS


Key Elements (2 of 2)

Screening Evaluation– Allows implementation without

topical review and approval for: Revisions that are consistent with

NRC precedent / prior NRC approval Determinations based on

qualitative risk evaluations, using methods consistent with those previously approved Determinations based on

quantitative risk analyses with results meeting established acceptance criteria “SCREENING EVALUATION” PROCESS

(2c) – Prior Acceptance of Similar Methodologies

Direct Precedent:Are the guidance changes consistent with either direct NRC precedent associated with analogous applications?

OR

Analysis Method Precedent:Are guidance changes directly supported through application of improved analytical methods that use inputs, evaluation methods, and margins on acceptance criteria essentially the same as those previously approved by NRC for similar applications?

NRC approval of change(s) required prior to generic release for implementation.

(2e)Are the evaluation results sensitive to new OE or R&D results?

Release change(s) for generic implementation without NRC approval.

(2a) – Component Safety Function(s)Is the proposed change predicated on conclusions based on revised component safety function or consequence of failure assessment(s)?

(2b) – Impact on Availability of Future OEDoes the proposed change recommend complete elimination of future examinations for any distinct component location previously subject to periodic inspection?

NO

(2d) – Change in Risk

Qualitative Risk Assessment:Are the changes directly and clearly supported by a generic qualitative assessment of risk (e.g., FMEA) that concludes the proposed changes are, as a minimum, risk-neutral?

OR

Quantitative Risk Assessment:Are the changes directly and clearly supported by generic risk-based analyses that demonstrate the proposed changes have a negligible impact on level of safety using bases previously accepted by NRC?

NO

NO

YES

NO

(2f)Can bases for reevaluation to address new data be established and included as a condition of release for implementation?

NO

YES

YES

NO

YES

YES

YES


Limitations on Document Screening Process Use

Two general limitations on use of document screening are included

Reasonable constraints to ensure appropriate and conservative application of document screening by IPs:1) Process cannot be used to screen out guidance changes based on

new or revised component safety assessments or consequence of failure assessments

2) The impact on generation of appropriate OE to identify adverse performance trends must be considered


Plant-Specific Implementation Limitations

Documents “passing” document screening are “generically released for implementation” by the IP

However, prior to use of revised guidance generically released through screening, each plant must ensure that there are no plant-specific limitations that must be resolved prior to implementation

Examples:– License renewal commitments to implement specific revisions of

aging management guidance

– ASME Section XI relief requests crediting BWRVIP exams in lieu of performing ASME Section XI examinations of core support structures


Review and Documentation IP Review and Approval

– For documents screened out based on applicability evaluation (simple evaluation), no formal review and approval required. Screening is performed by IP and the result documented in the letter transmitting the report for committee review.

– For documents screened out based on a detailed screening evaluation, the evaluation details are subject to the same committee review and approval processes as the topical report itself.

Documentation– The introduction section of all reports containing NEI 03-08 mandatory or needed

guidance will state the implementation status

– Where applicability evaluation (simple evaluation) was used, the guidance document introduction section will note this conclusion

– Where detailed screening evaluation was applied, the guidance document introduction section notes the conclusion and provides a reference to the screening evaluation details

Ensures that program owners implementing the report guidance can access the screening evaluation details

Evaluation details may be documented either as appendix to the topical report or in separate IP correspondence


NRC Communication

Formal notification– Each NEI 03-08 IP must provide an annual “information only”

notification to NRC regarding application of the screening process

– Notification must include:

Listing of reports previously approved by NRC via SE that have been revised or replaced using document screening

Summary statement regarding the screening basis used

– Evaluation details may be provided to NRC upon request

Informal communication– All NEI 03-08 IPs will continue to communicate with NRC in a

transparent manner, including use of document screening process


The Materials Degradation Matrix and

Issue Management Tables


NEI 03-08 Integrated Materials Issues Strategic Plan

Provides Systematic Approach to Managing Materials Issues– Identify vulnerabilities

– Assess condition (inspect & evaluate)

– Mitigate degradation initiation and propagation mechanism

– Repair or replace as required

Approach Used:– Degradation Matrix and Issue Management Tables

Degradation Matrix and Issues Management Tables to be maintained as living documents with annual updates


Industry Materials Degradation and Issue Management Table Approach

Develop a fundamental understanding of the degradation phenomena/mechanisms

Perform operability and safety assessments Develop Inspection and evaluation guideline Evaluate available mitigation options Develop repair & replace options Monitor and assess plant operation experience Obtain regulatory acceptance

Materials Degradation Matrix (MDM) and Issue Management Tables (IMT) are effective materials aging management tools in support of industry’s Materials Degradation and Issue Management Initiative

MD

MIM

Ts


Materials Degradation Matrix (MDM)

MDM provides a comprehensive listing of potential degradation mechanisms for existing LWR primary system componentsAssesses the extent to which applicable degradation

mechanisms are understood Evaluates the state of industry knowledge worldwide

associated with mitigation of applicable degradation mechanisms Documents the results of an expert elicitation processProactively identifies potential challenges to avoid surprises Identified Strategic Long Term Operation (LTO) Issues in

Materials Degradation Current Revision 3, 2013 (EPRI document 3002000628)


Color Chart Presentation of MDM Results

Blue lack of data to establish degradation applicability

Green well characterized, little or no additional research is needed

Yellow ongoing R&D efforts to resolve uncertainties in near-term time frame

Orange insufficient R&D to resolve uncertainties in a near-term time frame


MDM Results – BWR Pressure Boundary


MDM Results---- BWR Reactor Internals


MDM Results – PWR Pressure Boundary


MDM Results – PWR Reactor Internals


MDM Results - Steam Generator Tubes


The Issue Management Tables


Example IMT – BWR Reactor Pressure Vessel


Example Gap Description – BWR


Example IMT – PWR Reactor Pressure Vessel


Example Gap Description - PWR


Available at http://epri.com

EPRI Materials Degradation Matrix, Revision 3 (EPRI Report 3002000628)

BWR and PWR Issue Management Tables have been updated to reflect MDM extension to 80 years and beyond– BWR-167NP, Rev. 3 (EPRI Report 3002000690)– MRP-205, Rev. 2 (EPRI Report # 1021024)


Latest update


Materials Degradation Matrix (MDM) Revision 4

EPRI tool for capturing knowledge gaps associated with age-related degradation of primary system materials Identified in NEI 03-08 as

key element in proactive management of materials degradationPeriodically reviewed and

revised as appropriate


Revision 4 Objectives

Update state of knowledge as appropriate based on completed R&D and recent operating experience – No new issues identified

Improve ease of use through:– Elimination of “LTO tags”– Simplification of explanatory notes– Relocation of engineering-related issues in the MDM to appropriate

Issue Management Tables (IMTs)

Additional objective of Revision 4 is update of results for CANDUs and addition of results for VVERs


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