ML20153E965

Ro:On 880813,Kaman Vent Stack a Radiation Monitor RI-VG-179 Declared Inoperable.Caused by Central Processing Unit Board Malfunction.New Board Ordered & Expected to Be Received on 881009

ML20153E965
Person / Time
Site:	North Anna
Issue date:	08/29/1988
From:	Cruden D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
88-575, NUDOCS 8809070079
Download: ML20153E965 (3)

Text

- _ _ _ - - _ _ - _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ ___ _-_____________________________ _ _ - ____ _- ___

[ .J \

"~U .

ll '

VIHOINI A F.lmcTHIC AND l'OWHH COMi%NY 14 senxoxis, Vinonnu utsen August 29, 1988 i

). M. Ca n am a Vara Peassa.umt Nat mas United States Nuclear Regulatory Commission Serial No.88-575 '

Attention: Document Control Desk NAPS /DEQ/deg Washington, D. C. ?0555 Docket No. 50-338 -

License No. NPF-4 Gentlemen,  !

VIRGINIA ELECTRIC AND POWER COMPANY .

l NDkTH ANNA POWER STATION UNIT 1 M AN PROCESS VENT RADIATIO O ONITOR i RI-VG-179 At 2330 hours0.027 days <br />0.647 hours <br />0.00385 weeks <br />8.86565e-4 months <br /> on August 13, 1988, with Units 1 and 2 at 100 percent power  !

(Mode 1), the Kaman Vent Stack "A" Radiation Monitor, RI-VG-179, (EIIS System Identifier WE, Component Identifier MON) was declared inoperable. The radiation monitor was declared ineperable because the partneters being monitored processing unit were being)

(CPU spontaneously would not operate. Tworeset additional to the default radiationvalues monitorsandinthe central the same release path were indicating normal radiation levels during this period. Action Statement 35 of Technical Specific 3 tion 3.3.3.1 requires that the radiation tronitor be returned to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or initiate the alternate method of monitorin0 and prepare a Special Report.  !

Since this action statement expired at 2330 hours0.027 days <br />0.647 hours <br />0.00385 weeks <br />8.86565e-4 months <br /> nn August 16, 1988, with the f radiation monitor still inoperable, this event is reportable pursuant to f Technical Specification 6.9.2.

Investigation into the cause for the inoperable radiation monitor revealed that the CPU board had malfunctioned. A new CPU board has been ordered and is expected to be received by October 9, 1988. At that time, the new CPU board  !

will be installed in RI-VG-179, functionally tested, and if satisfactory <

results are obtained. RI-VG-179 will be returned to service. This Special l Report will be updated if additional problems delay returning RI-YG-179 to ,

service after the new CPU board has teen installed. l l

l l

l 8809070079 880829 ADOCK 0500 jG ff).%

DR 1 i

This event posed no significant safety implications because the Westinghouse Vent Stack "A" kadiation Monitors, which provide high radiation indication to the Control Room via a strip chart recorder, common alarm, alarm lights, and gaseous and particulate meters, remained operable throughout this event.

Additionally, the Nuclear Research Corporation Radiation Monitors continued to operate throughout this event as the Technical Specification required preplanned alternate monitoring method on the "A" Vent Stack.

Very truly yours, S de cc: U.S. Nuclear Regulatory Commission 101 Marietta Street, N. W.

Suite 2900 Atlanta, Georgia 30323 Mr. J. L. Caldwell NRC Resident Inspector North Anna Power Station

s KANAN RADIATION MONITOR RI-CW-179 EECEEDED T.S. ACTION STATEIG_NT I. VERIFICATION OF ACCURACY

1. Deviation Report 88-649

2. Conversation with John Patterson on 8/22/88

3. Conversation with Gary Jewett on 8/23/88

4. Action Statement for RI-GW-179 entered at 2330 hrs on 8/10/88

11. ACTION PLAN

1. The Instrument Department should be assigned to notify M. L. Bowling when RI-VG-179 has been returned to service. If any additional problems vera encountered after the new CPU board was installed which caused a delay in returning RI-VG-179 to se rvice this should be mentioned. This notification is necessary because we committed to update the Special Report if additional problems delayed returning RI-VG-179 to service af ter the new CPU board had been installed. A due date of October 15. 1988 should be adequate.

2. The Special Report will be updated by the Licensing Department if RI-VG-179 is delayed in being returned to service due to additional problems encountered after the new CPU board is installed.

3. As a result of the Special Reporr submitted on August 17, 1988 on RI-CW-178 Technical Services has been assigned to evaluate a change to Table 3.3-6 of Technical Specification 3.3.3.1. A due date of 11/15/88 was requested.

I 1

b l

I i

.- .- .. - - - . - .-