ML20129H809

Informs That Encl Engineering Evaluation Rept AEOD/E508 Re Operating Experience Involving Sys Disturbances Has Potential Significance to Resolution of Unresolved Safety Issue A-46 on Seismic Qualification of Equipment

ML20129H809
Person / Time
Issue date:	05/24/1985
From:	Seyfrit K NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Kniel K Office of Nuclear Reactor Regulation
Shared Package
ML20129H813	List: ML20129H809 ML20129H844 ML20129H865
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR AEOD-E508, NUDOCS 8506070664
Download: ML20129H809 (2)

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May 24, 1985 HEHORANDUM FOR: Karl Kniel, Chief Generic Issues Branch Division of Safety Technology Office of Huclear Reactor Regulation FROM:

Karl V. Seyfrit Cnief Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data

SUBJECT:

PLANT OPERATittG EXPERIENCE HAVING POTEriTIAL SIGilli'ICANCE TO THE RESOLUTION OF USI A-46 AE00 has recently completed an engineering evaluation concerning nuclear plant operating experience involving system disturbances caused by bumped electro-mechanical components. Our engineering evaluation report on this subject, which has been enclosed for your infonaation, found that enclosed switches, relays, transmitters and possibly relays in circuit breakers are among the most sensitive electro-mechanical devices in a nuclear plant.

A physical disturbance will frequently change the output states of these conponents.

Bumped components have resulted in reactor scrams, safety systen isolations, trips and initiations, and loss of power to safety systeas. Follow-up investigations of several bumped components which tripped or disabled a safety systea, found that the component did not appear to meet current seismic qualification standards in all cases.

The data collected indicates that enclosed switches, relays, transmitters and possibly relays in circuit breakers would be among the most sensitive (i.e., most likely to change state) electro-mechanical components in a plant during a major seismic disturbance.

Based on our review and evaluation, we would suggest that the results of this study be considered by the nenbers of your staff responsible for the resolution of USI A-46, " Seismic Qualification of Equipment in Operating Plants."

In particular, as noted in the report, we would suggest that the aforementioned classes of components, and their potential for causing unacceptable system transients or conditions, be considered by the HRC staff during the Phase 11 review of the proposed resolution of USI A-46.

8506070664 850524 PDR QTECI QSCA-46 PD.'t

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If you or any memkrs of your staff have any questions regarding this matter, please contact Stuart Rubin (X24436) of my staff.

l-g Karl V. Seyfrit, Chief Reactor Operations Analysis Branch Office for Analysis ard Evaluation of Operational Data

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