ML20033H108
| ML20033H108 | |
| Person / Time | |
|---|---|
| Issue date: | 04/06/1990 |
| From: | Richardson J Office of Nuclear Reactor Regulation |
| To: | Tipton T NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| NUDOCS 9004180181 | |
| Download: ML20033H108 (5) | |
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Mr. Thomas E. Tipton, Director Operations, Management and Support Services Division Nuclear Management and Resources Council Suite 300 1776 Eye Street, N.W.
Washington, D.C.
20006-2496
Dear Mr. Tipton:
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SUBJECT:
MOTOR-0PERATED VAL C PERFORMANCE PREDICTION PROGRAM PROPOSED BY THE ELECTRIC POWER RESEARCH INSTITUTE On March 22, 1990, the NRC staff held a public meeting with representatives of the Nuclear Management and Resources Council (NUMARC) and the Electric Power Research Institute (EPRI) to discuss the motor-operated valve (MOV) performance prediction program proposed by EPRI.
The MOV performance prediction program is being planned to enable the industry to respond in a coordinated manner to the concerns regarding the operability of MOVs under design-basis conditions. These concerns led the NRC to issue Generic Letter 89-10. " Safety-Related Motor-0perated Valve Testing and Surveillance," which requests holders of nuclear power plant operating licenses and construction permits to establish programs for testing, l
I inspecting, and maintaining MOVs in safety-related systems to provide assurance of their operability.
In tne generic letter, the staff reccmends that licensees and permit holders test MOVs in situ under design-basis con-ditions, where practicable, because of the uncertainty associated with current analytical techniques for demonstrating the operability of MOVs under those conditions.
For those MOVs where such testing is not practicable, licensees l
and permit holders will need to develop alternative methods of demonstrating l
MOV operability under design-basis conditions. The difficult task of justifying those alternatives may exceed the available resources of individual licensees or permit holders. Therefore, it is important that the industry work together to develop justifiable alternatives to testing MOVs in situ under design-basis conditions.
The primary objective of the EPRI program is the development of a validated M0V performance prediction methodology that (1) can be used, in combination with a static or reduced differential pressure test, to predict MOV o
performance at design-basis conditions, and (2) will provide a technically defensible alternative to testing of MOVs in situ under design-basis conditions.
In our view, a performance prediction program will provide the only viable path for most nuclear utilities to respond to Generic Letter 89-10. The staff is encouraged by the activities that EPRI is undertaking to address this serious issue. Although the program is in the early stages of development, the staff believes that, on the basis of the presentation, EPRI has made a credible effort at planning the proposed program. As discussed in d- '3 the enclosure, several points should be considered during the continuing
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Mr. Thomas E. Tipton 2
If fully developed and completed, the EPRI program will constitute a significant step toward ensuring the proper performance of MOVs. Other aspects of the T V performance issue, such as guidance for the establishment of comprehensive MOV programs at nuclear power plant sites and for the training of personnel involved in MOV activities, also need to be addressed by the industry. The staff recognizes that it may be more appropriate to address those aspects of the MOV issue apart from this EPRI program.
We appreciate the opportunity to review the MOV program proposed by EPRI. As the planning process continues, we would like periodic updates on its progress so that we may provide coments or pertinent information from operating experience. These future meetings would help ensure that the EPRI program establishes a methodology for demonstrating that MOVs will operate under design. basis conditions that is acceptable to the NRC staff.
If you have any questions on our comments, please contact me at (301) 492-0821 or Ledyard B. Marsh, Chief of the Mechanical Engineering Branch, at (301) 492 0902.
Sincerely.
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James E.yk... tlchiVds'o'n,'T"fr~ector
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n Division of Engineering Technology Office of Nuclear Reactor Regulation cc: John Hosler, EPRI Clive Callaway, NUMARC
Enclosure:
As stated Distribution:
Central Files:
TScarbrough Valve Distribution List PDR TScarbrough CHRON EMEB RF ESullivan DET RF LBMarsh
- See previous concurrence
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- 4/4/90
- 4/5/90
- & /b/90 (Dy phone) 0FFICIAL RECORD COPY Document Name: SCARBROEPRILETTER l
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Mr. Thomas E. Tipton
-2 If fully developed and completed, the EPRI program will constitute a significant step toward ensuring the proper performance of MOVs. Other aspects of the MOV performance issue, such as guidance for the establishment of comprehensive MOV programs at nuclear power plant sites and for the training of personnel involved in MOV activities, also need to be addressed by the industry. The staff recognizes that it may be more appropriate to address those aspects of the MOV issue apart from this EPRI program.
J We appreciate the opportunity to review the MOV program proposed by EPRI. As the *1anning process continues, we would like periodic updates on its progress so U.at we they provide comments or pertinent information from operating experience. These future meetings would help ensure that the EPRI program establishes a methodology for demonstrating that MOVs will operate under design. basis conditions that is acceptable to the NRC staff.
If you have any questions on our comments, please contact me at (301) 492-0821 or Ledyard B. Marsh, Chief of the Mechanical Engineering Branch, at (301) 492 0902.
Sincerely, James E. Richardson, Director Division of Engineering Technology Office of Nuclear Reactor Regulation i
cc: John Hosler, EPRI Clive Callaway, NUMARC Enclosure 1
Distribution:
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DATE
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- Y/4/90
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Enclosure NRC STAFF COP 91ENTS ON i
THE PROPOSED MOV PERFORMANCE PREDICTION PROGRAM PRESENTED BY EPRI ON MARCH 22, 1990 1
1.
A wealth of experience with the operation of motor-operated valves (MOVs) exists in the nuclear utility organizations.
Because of the complex phenomena associated with MOV operation under various conditions. EPRI should also ensure that individuals who have significant experience in valve design participate in the development of the program.
2.
Certain individuals and organizations within the Federal Republic of Germany have considerable experience in the design, testing, and operation of MOVs. Consequently, EPRI should attempt to incorporate information and guidance from those individuals and organizations into its program. For example, KWU and Bechtel-Siemens have been involved in the development of.a valve calculational-predictive model.1That model was used to predict stem forces needed to close the valves-during the-recent MOV blowdown tests performed by Idaho National Engineering Laboratory (INEL) and was found to require refinement.
3.
EPRI should carefully review the results of the NRC research on MOV operat?on, such as INEL " phase one" blowdown test results reported in NUREG/CR-5406 (October 1989) and INEL " phase two" blowdown test results that will-be discussed at the public meeting on April 18. This information should be incorporated into the EPRI program plan. This will enable EPRI to avoid duplication of effort and to focus its program on those areas of MOV operation that are not well understood.
4.
During its presentation, EPRI estimated the number of MOVs "potentially applicable" to the recent tests conducted as part of the NRC research on MOV operation.
Based on operating experience, the number of applicable MOVs estimated by EPRI may be understated.
EPRI should reconsider this estimate following the April 18 public meeting on the recent MOV tests.
5.
The MOV performance prediction methodology to be developed by EPRI should accommodate aging' effects where 4ta from the testing of an MOV are to be applied to an MOV that has seen more severe or longer service.
6.
The EPRI testing should be conducted under a documented quality assurance (QA) program. Among the aspects to be addressed by the QA program are data collection and test equipment calibration.
7.
Based on experience with NRC research activities, the EPRI estimate of $12 million to complete the proposed program may be low.
For example, the EPRI proposal to test 60 MOVs under design-basis conditions (with only 10 to be tested under hot water or steam conditions) is likely to be insufficient to validate the applicability of the EPRI methodology to a large percentage of the MOVs within the industry.
In addition, the EPRI approach relies to a 4
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f significant degree on the development of a analytical-calculational methodology early in the program. EPRI may need to rearrange the schedule to provide test data for use during development of this model with the performance of later tests for model validation and qualification. These additional tests are important to reduce the uncertainty in the model's stem force predictions.
If that uncertainty is excessive, it might not be possible to set the MOV operator switches so as to bound the uncertainty and, at the same time, to remain within the mechanical and electrical capability of the valve. Further, while EPRI. indicated that valve design and tolerances would be evaluated to identify anomalous MOVs, additional testing may also be needed to reveal valves that exhibit anomalous behavior during various pressure and flow conditions.
so ensure that the EPRI methodology will be applicable in an acceptable manner to a large fraction of the MOVs within the scope of Generic Letter 89-10, EPRI should consider establishing a more extensive test matrix for model development validation and qualification.
In addition,-EPRI should develop the program su,ch that guidance is provided to the industry as important portions of the program-are completed.
8.
Peer review of the MOV performance prediction methodology, when completed, would facilitate wide acceptance. For example, the national laboratories could provide valuable comments regarding the acceptability of the EPRI methodology. This peer review might be accomplished in cooperation with a national engineering organization. With respect to the distribution of the program results for peer review, we understand that EPRI may be concerned about the proprietary nature of its work.
If EPRI discovers safety problems during its activities, however, Part 21 of Title 10 in the Code of Federal Regulations requires that the staff be alerted to those problems which may affect the proprietary status of the information. To facilitate the wide availability and peer review of the EPRI program results. EPRI should encourage all utilities to participate in this joint effort. Such participation may be particularly important for most licensees in that they likely will not be able to respond completely and adequately to Generic Letter i
89-10 without the benefit of an industry-wide effort, i
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