ML17252A783
| ML17252A783 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/04/1975 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | James Keppler NRC/RGN-III |
| References | |
| BBS 230-75 | |
| Download: ML17252A783 (2) | |
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Bas Ltr. #230-75 Regulatory' Dresden Nuclear Power Station R. R. #1 Morris, Illinois April 4, 1975
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Mr. James G. Keppler, Regional Director ii
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Directorate of Regulatory Operations-Region III
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U. S. Nuclear Re... *1 atory Ccmmission
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SUBJIDr:
REPORT OF UNUSUAL EVEm' Plm SIETION 6.6.C OF THE TEX;BNICAL....SP.~I:Fi~IONS CORE SPRAY VALVE M0-3=14o2-4A
References:
- 1. Regulatory Guide 1.16 Rev. 1 Appendix A
- 2. Notification of Region III of u. s. Nuclear Regulatory Ccmmission Telephone: Mr. P. Johnson at 1500 holirs on March 24, 1975 Report Number:
50-249/1975-18 Report Datei April!R1!, 1975 * *
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Occurrence Date:
VJ&rch 24, 1975 Facility: Dresden Nuclear Power Station, Morris, Illinois.
IDP.Nl'IFICATION OF OCCURR!X;E Core Spray Valve 3-14o2-4A failure to close.
CONDITIONS PRIOR TO OCCURRENCE Prior to the failure of core spray valve 3-14o2-4A to close the unit was in the "run" mode with thermal power at 1265 megawatts. The unit had an"electrical load of 4o8 megawatts, an4 the core spray monthly surveillance testin8 was in progress.
DF.SCRIPI'ION OF OCCURRENCE On March 24, 1975 at about 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br /> on core spray valve 3-14o2-4A failed
- to close electrically during surveillance testing. From previous failures it has been determined that the 3-14o2-4A valve cannot be closed electrically while a core spray pump is running. As corrective measures for previous failures a unit operator was stationed at_the valve prior to its operation to manually close the valve when neoess~:y.
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.... Mr~, James G. Kepple.i.w
- AP;ril 4, 1975 DESIGNATION OF APPARmr CAUSE OF OCCURRmcE From previous failures.it has been determined that the :>-14o2-4A valve draws a higher *than rated current during 1 ts operation. The higher current draw could be due to an internal valve problem or an internal motor problem.
It is presently believed that the cause *of the problem is due to a fault in the motor operator. However, prior. :tc) changing the motor operator the valve will be disassembled and inspected during the* next unit outage wh+/-.2'!9
- is presently scheduled for the end of April. The results of the valve inspection will determine the cause of the failure more accurately. Following the valve inspection a foll0wup letter will be*sent to Region III outlining
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ad.di tional corrective actions. Also, since no ad.di tional,o~'.bi ve actions will be made until a:t'ter the valve inspection any addi tion&i7aiiures of the valves during surveillance testing will not be reported to Region III* except by telephone.
ANALYSIS OF OCCURRENCE The failure of the core spray valve :>-14o2-4A to close electrically did not place the* safety of the plant or public in Jeopardy. The :>-1402-4A valve is
-used for test purpos~s only and is.not. required for system operability.
C~TIVE ACTIONS
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The immediate corrective action taken was. to close the valve manually. A Wlit operator has been stationed at the :>-1402-4A valve to manually close the valve ~en necessary. Additional corrective actions will be made following an inspection of the :>-14o2-4A valve during the next refueling outage.
FAILURE DATA The :>-1402-4A valve has failed to close electrically while a core spray pump wa8 running since December 1974. All previous failures occurred while performing monthly surveillance testing.
BBS:~ssmp File/NRC