ML19323F132

LER 80-001/03L-0:on 800423,w/unit in Mode 6 Following Fuel Loading,Rhr Sys Inlet Valve MOV-2700 Ran Closed,Causing Loss of Operable RHR Loop.Caused by Blown Signal Comparator Card Power Supply Fuse in Process Control Sys.Card Replaced

ML19323F132
Person / Time
Site:	North Anna
Issue date:	05/22/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19323F127	List: ML19323F126 ML19323F132
References
LER-80-001-03L-01, LER-80-1-3L-1, NUDOCS 8005280577
Download: ML19323F132 (2)

Text

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' l o 12 l l On April 23, 1980,with the unit in Mode 6 following initial fuel loading, Residual Heat l Io i3 l l Removal System inlet valve MOV- 2700 ran closed causing loss of the operable RHR loop. l l o l 41 l Because the core was new and no decay heat was being generated when the isolation of thel l0Isl lRHR System occurred, the health and safety of the general public were not affected. Repopt-1 o Is I l able pursuant to T.S. 6.9.1.9.b. l 1ol7l l l 1 o la I I I 7 8 9 80 C E OE S SC E COMPONENT CODE Sb8 CODE SL E l0l91 lC lF lh l Elh l G lh l Il Nl Sl Tl Rl Ulh lC lh lZ lh 7 8 9 10 11 12 13 18 19 20

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,, ,7, jplaced and the new card satisfactorily recalibrated in accordance with applicable l

,, ,3, ycalibration procedures. The instrument loop was then returned to service. l l i 14 1i l 7 a 3 80

$A  % PCWER OTHER STATVS 015 O RY DISCOVERY DESCRIPTION

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NAYE OF PRE *ARER W. R. CARTWRIGHT (703) 894-5151 PwCNE: S,

Virginia Electric an1 Power Company North Anna Power Stt; ion, Unit #2

Attachment:

Page 1 of 1 Docket No. 50-339 Report No. LER 80-01/03L-0 Description of Event On April 23, 1980, with the initial core loading completed and the unit still in Mode 6, the Residual Heat Removal System was rendered inoperable when system inlet valve MOV-2700 went closed. This event is contrary to T.S. 3.9.8 and reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence The Residual Heat Removal System is used during refueling to remove residual heat from the core and maintain Reactor Coolant System temperature within required limits. Because the core contained new fuel and there was no decay heat being generated when the RHR System became inoperable, the health and safety of the general public were not affected. This is a random failure and no generic implications exist.

Cause of Event MOV-2700 closed because the power supply fuse on the signal comparator (NAL) card in the Reactor Coolant Loop Pressure Process Control System blew. This particular control system provides the permissive signal for the residual heat removal loop isolation valves interlock circuit.

Immediate Corrective Action The loop signal comparator card was removed and replaced with a new card. The new NAL card was then satisfactorily recalibrated in accordance with applicable calibration procedures and the loop returned to service.

Scheduled Corrective Action No scheduled corrective action is required.

Actions Taken to Prevent Recurrence No further actions are required.

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