ML19254F486

LER 79-139/03L-0:on 791011,during Testing of RM-RMS-159, Power Fuses for Containment Particulate & Gas Radiation Monitors Blew.Caused by Short in Solenoid Valve K5.Solenoid Valve Coil Replaced & Monitors Returned to Svc

ML19254F486
Person / Time
Site:	North Anna
Issue date:	11/09/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19254F484	List: ML19254F483 ML19254F486
References
LER-79-139-03L, LER-79-139-3L, NUDOCS 7911090517
Download: ML19254F486 (2)

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? 6 60 61 90CKET NUMBER 68 63 EVENT DATE EVENT DESCRIPTION AND P;tOBABLE CONSEQUENCES h O 21 1 On October 11, 1979, with the unit in refueling mode, the Containment Purge and I o 3  ; Exhaust isolation system was rendered inoperable when the power fuses for the contain- l o 4,  ; ment particulate and gas radiation monitors blew during periodic testing of RM-RMS-159. l o 33 Since each purge and exhaust penetration providing direct access from the containment 1 o e atmosphere to the outside atmosphere was closed, the health and safety of the general l o 7 ;public were not affected. Reportable pursuant to T.S. 6.9.1.9.b. l 0 a l 1

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o lThe fuses blew when the sample pump control switch was placed in the stop position l l3 ii; lbecause the coil on purge solenoid valve K5 was shorted out. The solenoid valve coil I

,, , ;was replaced and the radiation monitors were returned to service thus restorina the I m 3 ; Containment Purge and Exhaust Isolation System to operable status, i 4 l _

l 7 8 9 83 ST S  % POWE R OTHER STATUS IS O RY DISCOVERY DESCRIPTION Ii ls l [Jij@ [ 0l 0 l 0 l@l NA l lB l @ l Surveillance Test l ACTIVITY CO TENT RELE ASED OF RELEASE A90VNT OF ACTIV:TY LOCATION OF RELEASE i s L7J @ Lz_J@l NA l l NA l 7 8 3 10 11 44 45 80 PERSONNEL EXPOSUAES NUMBER TYPE CESCRIPTION

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Virginia Electric and Power Company North Anna Power Station, snit #1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-139/03L-0 Description of Event On October 11, 1979, with unit ir: Mode 6, the power fuses for the containment particulate and gas radiation monitors blew when the control switch for the sample pump was placed in the stop position during the performance of the monthly surveillance test. This resulted in the inoper-ability of the Containment Purge and Exhaust isolation system which is contrary to T.S. 3.9.9 and reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence The Containment Particulate and Gas Radiation MoHtoring Systems are used as a primary means of detecting a Reactor Coolant System leak. The systems also provide a signal to secure and isolate the Containment Purge Supply and Exhaust Systems on a high-high particulate or gas level in Mode 6. Each of the purge and exhaust penetrations providing direct access from the containment atmosphere to the outside atmosphere were closed, As a result, the health and safety of the general public were not affected by this event. There are no generic implications associated with this occurrence.

Cause The cause for the fuses " owing when the sample pump control switch was placed in the stop position .s a shorted out coil on purge solenoid valve K5.

Immediate Corrective Action New power fuses were immediately installed and the defective solenoid valve coil was replaced. Both radiation monitors were then returned to service and the periodic test was reperformed satisfactorily restoring the Containment Purge and Exhaust isolation system to operable status.

Scheduled Corrective Action No scheduled corrective action is requirad.

Actions Taken to Prevent Recurrence No further actions are required.

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