ML20043H076
| ML20043H076 | |
| Person / Time | |
|---|---|
| Issue date: | 06/15/1990 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Hutchins T AUTOMATIC VALVE CORP. |
| Shared Package | |
| ML20043H077 | List: |
| References | |
| NUDOCS 9006210546 | |
| Download: ML20043H076 (2) | |
Text
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JUN 151990 Mr. Todd Hutchins Automatic Valve Corporation 41144 Vincenti Court Novi, Michigan 48050
Dear Mr. Hutchins:
Subject:
preliminary Case Study Report on Solenoid Valve problems at U.S. Light Water Reactors A preliminary AEOD case study report, " Solenoid Valve problems at U.S. Light Water Reactors," is enclosed. The study analyzes and evaluates operational uperience and safety implications associated with failures and degradations of solenoid-operated valves (SOVs) at U.S. LWRs.
It focuses upon the vulnerability of safety-related equipment to comon mode failures or degradations of SOVs..
The report presents information on more than 25 events in which comon-mode failures or degradations of over 600 SOVs were affected, or had the potential to affect, multiple safety systems or multiple trains of individual safety systems. Although plant safety analyses do not address such comon-mode failures or degradations of safety systems, operating experience presented in the report indicates that they have occurred and are continuing to occur.
A number of events in which safety systems have been adversely affected by degradations or f ailures of SOVs are gonsidered significant precursors. The case study notes that 50V problems permeate almost all U.S. nuclear power plants, and that they encompass many aspects of the 50Vs' design, maintenance, and operation. The case study also notes that individual SOV manufacturer's practices regarding guidance with respect to testing and maintenance contribute towards the observed problems. The report presents six recomendations which, if implemented, should reduce reactor accident risks by reducing the likelihood for comon-mode failure or degradation of SOVs affecting multiple safety systems or multiple trains of individual safety systems.
In accordance with our " peer review" process, prior to the finalization and distribution of our case study reports, we are providing you and other vendors who provided input to the case study with a copy of the preliminary report for review and coment.
We request that you focus your review primarily on the accuracy and completeness of the technical details (i.e., coments are being solicited on the technical accuracy of the report). The findings, conclusions, and recomendations are provided for your information in order that you may understand the significance we place on these events and, therefore, obtain a more complete picture of the total report. Changes to the findings, conclusions, and recomendations will be considered only if the underlying information concerning the details of plant design or systems operation is in error. We ask that coments be provided in writing, f34 ac m e-em 9006210346 900613 PDR opg g
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L Mr. Todd Hutchins
-P-Since we wish to finalize and issue the report shortly, we ask that any comments be received by us within 30 days from receipt of this preliminary report.
If you require additional time beyond that point, please let us know.
If you or your staff have any questions regarding this study, please feel free to contact me or Dr. Hal Ornstein at (301) 492-4439.
Sincerely, Original cigned by:
[h"oEff N."R6Nik, Direstor Division of Safety Programs Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated Distribution:
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