ML19248D371
| ML19248D371 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/16/1979 |
| From: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Mattson R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19248D372 | List: |
| References | |
| NUDOCS 7908150684 | |
| Download: ML19248D371 (1) | |
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UNITED STATES n
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7, NUCLEAR REGULATORY COT.lf.1tSSION 3.)kl'i-'5l) l$
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JEMORAliDUf! FOR:
Roger J. !'attson, Jirector, Division of Systems Safety, Cffice of Huclear Reactor Regulation F RO.M :
Nomar C. "oseley, Director, Division of Reactor Operations Inspection, Office of Inspection and Enforcer.ent S L'SJ ECT:
HPI ?bMP PEP.FCR."A:.'CE DURIi!G THE T."I ACCIDENT This is an interin respcose to your June 20, 1979 memorandum to V. Stello, subject above. Additional information will be supplied liter.
At the present time, anual starting difficulty for.ourp 13 sppears to be caused by " contact bounce." The anual starting switch has a pistol grip handle. hich is twisted or rotated to actuate the contacts.
Computer print-outs indicate on some occasions the occurrence of a series of coen and close cycles of a few milliseconds duration.
Since the operator could not have operated the switch this fast, it is assumed that some vibration Fechenism
.zas the cause (contact bounce).
Ne know that scr.e field.Todifications had been made on these suitches.
'le are now follo..iing up on what '..as done, Fow evaluated, by ahom, testing, quality considerations, etc.
Since this seems to be related to ranual starting, and failures have not been riorted in surveillance testing, it probably.ould not affect auto starting (Safety Injec tica)' hc'..ever, this Fas not yet been rult d out.
The ir'.astigation r port will attribute vost of the pur.p trips to operator action.
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.arman C. ioseley Di rector Division of Peactor C;erations Ins?cc'ica
'iffice of Inspecticn and Eniccce ant cc:
J. ". Allan, RI R. O.
'artin, RII 790815cG3
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