ML19338C997
| ML19338C997 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/07/1975 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | |
| References | |
| 473-75, NUDOCS 8009150563 | |
| Download: ML19338C997 (2) | |
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/[j]'-], / One First IEGonal Plaza, Ch2 ago, thinois commd=salth Edison (5
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j Chicago, Illinois 60690 Regulatory QCy.
BBS Ltr. #4'73-75 Dresden Nuclear Po.cer Station R. R. #1 Morris, Illinois 60450
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17 z-Mr. James G. Keppler, Reginnal Director c' 'O,,,
l%;U,,.,t Directorate of Regulatory Operation-Regie III s$-i.
U. S. Nuclear Regulatory Comission
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799 Roosevelt Road IeN N/
Glen Ellyn, Illinois 60137
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SUBJECT:
REPORT OF UNUSUAL EVEtf? PER SECTION 6.6.C OF THE TECHNICAL SPECIFICATIONS FAILUME OF CORE SPRAY VALVE MO-CS33 TO OPERATE g3M i 'i,y.S
References:
- 1) Regulatory Guide 1.16 Rev. 1 Appendix A g
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- 2) Drawing Number M-595
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Report Number: 50-10/75-11
@d-AUG 191975 6
s Report Date: August 7, 1975
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,g cw Occurrence Date: July 23, 1975 gi 1 Facility: Dresden Nuclear Power Station, Morris, Illinois IDENTIFICATION OF OCCURRENCE Core spray valve MD-CS33 failed to open during the monthly core spray valve operability surveillance.
I CONDITIONS PRIOR TO OCCURRmCs t
i Unit-1 was at a steady-state power Jevel of 475 wt and 136 we.
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DESCRIPTION OF OCCURRENCE At 0530 hours0.00613 days <br />0.147 hours <br />8.763227e-4 weeks <br />2.01665e-4 months <br /> on July 23, 1975, while performing the core spray valve operability surveillance, MO-CS33 failed to operate from the contm l room.
l Valve MO-CS32, the redundant valve, was i= mediately verified to be operable.
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- y August 7, 1975 Fe. James G. Ke er - a t
DESICHIATION OF APPAREtTP CAUSE OF OCCURRDICE (Crud Accu:ralation)
It was discovered that an An operator was sent to investigate the problem.
"open" signal from the control room woulcf automatically open the valve t
when the operating lever was engaged. The operator then opened the valve k
nanually. There was no indication of binding, An inspection of the valve revealed an accumulation of e n d on the valve stem section traversed by the driving nut. The crud was lodged in the threads, ea W 7 the stem to bind.
ANALYSIS OF OCCURRDICE The failure of valve MO-CS33 had no safety implications since the redundant valve MO-CS32 was operable at all times. The health and safety of the public were not jeopardized by this occurrence.
CORRECTIVE ACTION I:rediate corrective action was to inspect and clean MO-CS33 Further action will be to inspect and, if necessary, clean MO-CS32. Protective covers have been installed on both valve stems to help prevent a recurrence of this proble=.
FAILURE DATA A failure of this nature has never occurred before at Dresden.
N
. B. Stephenson b
Superintendent EBS:GJHismp Filef^30