ML20044B613
| ML20044B613 | |
| Person / Time | |
|---|---|
| Issue date: | 01/25/1993 |
| From: | Parczewski K Office of Nuclear Reactor Regulation |
| To: | Strosnider J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9302190149 | |
| Download: ML20044B613 (41) | |
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.E NUCLEAR REGULATORY COMMISSION I
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MEM0PANDUM FOR:
Jack R. Strosnider,Jr., Chief Materials and Chemical Engineering Branch 3
Division of Engineering, NRR
-1 FROM:
Kris Parczewski, Senior Chemical Engineer Chemical Engineering and Metallurgy Section Materials and Chemical Engineering Branch Division of Engineering, NRR THRU:
Robert A. Hermann, Section Chief Chemical Engineering and Metallurgy Section Materials and Chemical Engineering Branch Division of Engineering, NRR
SUBJECT:
MINUTES OF THE MEETING ON EROSION-CORR 0SION WITH NUMARC AND' EPRI, JANUARY 13, 1993 The subject meeting was held to discuss the issues related to implementation f
of the erosion-corrosion programs in nuclear plants. In introductory remarks Mr. Hermann outlined the problem facing the NRC when reviewing the erosion-corrosion programs in the licensees plants. Recent NRC audits have indicated that many utilities use different analytic-predictive methods or engineering i
judgment to select samples. for inspection rather than relying on the EPRI developed methodology.
This leads to some concerns for the NRC since these are sampling programs and there are no criteria for evaluating their effectiveness.
It would be very helpful if the industry under NUMARC guidance developed a set of guidelines which would describe acceptable methods to be used in developing erosion-corrosion programs.
Mr. Bindi Chexal presented EPRI work in erosion-corrosion. area.
He outlined historical development of the EPRI methodology resulting in producing CHECMATE Ji family of computer codes (CHEC,.CHECMATE, CHEC-NDE, CHEC-T and CHEXPERT). In addition to providing these codes to the industry and training utility personnel in their use, EPRI provides also assistance in solving different erosion-corrosion related problems by operating the CHECMATE Owner Group (CHUG) which provides a forum for exchanging ideas between its participants and EPRI cognizant personnel.
Currently, CHUG has 47 member organizations, including CANDU Owner Group and Naval Reactors. Mr. Chexal_ described future development of erosion-corrosion efforts at EPRI. These include development of an advanced predictive code CHECWORKS which would combine existing codes into one single code and thus facilitate prediction of erosion-corrosion.
Also, EPRI is in the process of preparing a document containing general recommendations for utilities on how to solve the erosion-corrosion problems.
These recommendations are of a general nature and are not limited to a specific application of the EPRI developed methodology. This document is in developing stage and will be available in the near future.
Finally, Mr.
Chexal discussed the answers to more common problems encountered by the CHECMATE users.
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9 J. Strosnider After Mr. Chexal's presentation, general discussion evolved around the role of industry in addressing the erosion-corrosion issues and the criteria for developing satisfactory erosion-corrosion programs.
NRC stated it was issuing an Information Notice informing that as a result of the recent audits and inspections of erosion-corrosion programs, NRC concludes that although the programs meet the intent of Generic Letter 89-08, there is a room for improvement.
Mr. Strosnider indicated that the industry should take the initiative in developing suitable criteria. NUMARC responded that although some effort could be made in that direction, it must be made clear that NUMARC could not be involved in developing criteria which could serve for plant inspections, because erosion-corrosion phenomena occur mostly in non-safety related portions of the balance of plant which are not covered by the NUMARC charter.
However, NUMARC indicated that following the issuance of an Information Notice by the NRC, it will act by informing the industry executives about the EPRI developed guidelines and the NRC concerns.
These guidelines will also be sent to the NRC (Strosnider), asking the NRC to provide its comments within one month.
After receiving the NRC comments, EPRI will issue these guidelines and, perhaps, NUMARC will endorse them. However, it will remain NUMARC's position that the guidelines are voluntary and, therefore, do not constitute a commitment of the industry.
A list of attendees and a copy of handouts are enclosed.
Originnt signed by:
K. I. Parczewski Senior Chemical Engineer
Enclosures:
- 1. List of Attendees
- 2. NRC Presentation
- 3. EPRI Presentation cc:
J. Richardson B. D. Liaw R. Hermann J. Davis J. Medoff DE:EMCB M DE:F)+CM/
cFFICE s-g y NAME KParczewski RHermann
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OFFICIAL RECORD COPY FILENAME: G:\\PARCZEWS\\NUMARC1. KIP
ATTENDEE 1 January 13, 1993 Meeting i
Alex Marion NUMARC Morris Schreim NUMARC Bindi Chexal EPRI Kris Parczewski NRC/NRR/DE/EMCB Jim Davis NRC/NRR/DE/EMCB Harold Gray NRC/ Region I Kevin Graney SERCH LICENSING /BECHTEL B. D. Liaw NRC/NRR/DE Jim Medoff NRC/NRR/DE/EMCB Jack Strosnider NRC/NRR/DE/EMCB Bob Hermann NRC/NRR/DE/EMCB h
a AGENDA FOR THE JANUARY 13, 1993-NRC - NUMARC EROSION / CORROSION MEETING-One White Flint North, Room 1-F19-10:00 am 5
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Introduction NRC Concerns and Issues Discussion Conclusions I
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CURRENT EROSION / CORROSION ISSUES i
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- 1. In response to Generic Letter 89-08 all licensees have implemented erosion / corrosion (EC) control programs.
- 2. Not all programs based on CHEC/CHECMATE or other predictive models.
- 3. Programs based primarily upon engineering judgnient may not be sufficient enough to predict susceptible locations.
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CURRENT EROSION / CORROSION ISSUES l
4.
Some inconsistencies with the use of CHEC/CHECMATE as predictive models:
improper selection of component geometry codes
. when opting to revalidate CHECMATE with inspection data - improper selection of Toir l
- 5. A lack industry guidelines / criteria for balance of plant l.
systems and components:
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for operation of degraded components for repairs /replacments u
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CURRENT EROSION / CORROSION ISSUES 4
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- 6. Higher than expected wear reported in safety-related, carbon steel piping:
Class 1 (BWR) feedwater system Class 2 (PWR) feedwater system t
Class 3 portions of main steam system (PWR)
- 7. For ASME Code class components, a Section XI repair / replacement required when acceptance criteria are exceeded.
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4 EPRl/NPD Summary ~of EPRI
& CHUG Activities in Flow-Accelerated Corrosion 1
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Presented to U. S. Nuclear Regulatory Commission l
January 13,1993 Bindi Chexal Electric Power Research Institute l
NSD DPM 55PP 1/5/931
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Background
(continued)_
Result was CHEC family of codes
- CHEC: Predicts FAC. wear rates & identifies-the most susceptible fittings in single phase lines
- CHECMATE: Predicts FAC wear rates in single.& two phase lines
- CHMMDE: Imports, displays, &. mang' ~
NDE!?i,6spection data
- CHEC-T: Structural evaluation of worn fittings
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CHEXPERT: Intelligent guidance
.EPRl/NPD
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Implementation Several publicized piping failures in 1990 & 1991 highlighted importance of implementation Industry has. responded aggressively
- Focus through CHUG & EPRI
-Two letters from Chairman of EPRI NPD Advisory Committee (W. Conway, VP APS) with l
self assessment questionnaires
- Training
- Financial. commitments
- Extensive plant modeling completed in 1992 &-
- in progress
EPRl/NPD (continued) 1
.47. members in 1992 representing 40.of 44' nuclear utilities
-5 consultants providing services in FAC
-Candu Owner's Group
- Naval nuclear. program; Participation from foreign utilities & vendors 4
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[- EPRl/NPD Typical Inspection Process 1
4 Reveiw system design & operation - identify susceptible systems Obtain design, as-built, & operating data Perform predictive analysis {CHECMATE)
Review predicted wear rates &Lremaining lifetime for each component t
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Typical Inspection Process (continu'ed) i L
- - Add inspection locations based on:
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- Industry experience-l-
- Plant experience L
L Conduct inspections: Use industry standards for
- Type of inspection (usually UT)
- Extent of gridding & inspection <
Size of grids Determine measured wear:: Standard methods
- Pointito aoint, blanket method, band method NSD l
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4 EPRl/NPD Keys to a Successful Frogram Corporate commitment I
Implement a well developed engineering approach Participate in experience sharing Education &; training Long term strategy to reduce high wear rates Update program as technology develops 4
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[ EPRl/NPD Development Activities
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CHECWORKS
-Third generation technology
-Integrate & ultimately replace the CHEC family of codes l
-Implement provisions of ASME Section XI, Subsection IWH
- Reverify predictive model L
-Expand modeling capabilities
-Better methods to determine wear
- Addition of advanced amines to chemistry. module
- Future releases.to address cavitation:& droplet impingement s
DPMSSPP 1/5/93 18
EPRl/NPD Training In-depth training classes Three day duration Free of charge to CHUG members and NRC 210 attendees in 1991 &~1992
- 28 NRC personnel DPM 55PP 159316
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EPRl/NPD Sharing of Industry Experience CHUG meetings & workshops
- Recent plant experiences
- Promote engineering approach
-Information on.CHEC family of codes
- Coordination with EPRI NDE Center d
- Related ASME! code activity
- Remedial & preventive measures-
- Repair & replacement issues T
.UT & RT inspection experiences
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- Related degradation measures-DPM SSPP 1/5/9314 c.
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v EPRl/NPD Some commonly asked questions and answers about industry's program on FAC k
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Q1.
What is the, recommended process for FAC inspections?
Is the process docymented?
A1.
The process is summarized in EPRI's "Recommenda,tions" document and in the training materials.
Q2.
How should inspection locations be chosen?
A2.
A combination of
-- predictive analysis-(CHECMATE) industry experience plant experience J
526PNKCAel 171/8S3.
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Is judgement alone adequate for choosing inspection locations?
A3.
No. This is not EPRI's recommendation.
t Q4.
Should safety.related systems be excluded from-the inspection program?
t A4.
No Nuclear Safety;
' 526PNKC,kel 18 1/8/93
s EPRl/NPD l
QS.
How widely is CHECMATE being used? Why isn't everyone using it?
AS.
Most plants now have CHEC or CHECMATE models of most major systems, or are in the process of developing i
them. Utilities typically budget 1+ years in advance, and CHECMATE models needed to be considered with other plant needs.
A few utilities still rely on experience based' programs.
The number of experience based programs. shrunk.
significantly.in 1992.
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Q6.
Should CHEC models be converted to CHECMATE?
A6.
This is EPRI's recommendation.
i Q7.
What is being done to make CHECMATE easier to use?
A7.
In the near term user support is provided by the training classes, hotline services, newsletters, and the Recommendations document.
i For the longer term, CHECMATE will be replaced by CHECWORKS which..has been designed to be more user.
friendly.
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Q8. What is being done to address OA issues?
A8. The " Recommendations" document contains a series of i
i checklists which the utility can use to document the plant l
evaluation.
Q9. We have noticed errors in.the CHECMATE models and input data. What is being done to eliminate such errors?
A9. Several approaches are being used
- EPRI is recommending that analyses be reviewed
-frequent training classes are offered
-the checklists from the " Recommendations" document should help i
-The tiered inspection approach should minimize effect-of errors:
- predictive analysis
- industry experience
- plant experience 526PNKCAel 21 1/8/93
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EPRl/NPD Q10. Determination of wear from inspection data seems to be t
a problem area. What is being done to help?
A10. Most problems involve the determination of initial component thickness when there is no baseline data. As more multiple inspection data becomes available,.this problem will significantly lessen.
In addition:
- CHEC-NDE has helped significantly l
- Use of the new " blanket method" to determine wear is more accurate than the band method and should help make analyses and inspection more consistent.
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