ML20112F124

Revised RO-SPR-84-018:on 841204,RHR Train B Suction Relief Valve Actuated.Caused by RCS Pressure Transient Resulting from Isolation of Letdown Flow.Pressure Control Valves Opened & Power Supply Lead Replaced

ML20112F124
Person / Time
Site:	Summer
Issue date:	01/03/1985
From:	Dixon O SOUTH CAROLINA ELECTRIC & GAS CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
SPR-84-018, SPR-84-18, NUDOCS 8501150396
Download: ML20112F124 (2)

Text

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SOUTH CAROLINA ELECTRIC & GAS COMPANY

,OSr OFFICE 764 CotuualA. SOUTH CAROLINA 292 8 8

%T::::.: 85 JAN 8 Pl:y suct... o..=ario~s January I,y 1985 Mr. James P. O'Reilly Regional' Administrator U.S. Nuclear' Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, GA 30323

SUBJECT:

Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Special Report (SPR 84-018),

Revision 1

Dear Sir:

Attached'is Revision 1 to Special Report 84-018 for the Virgil C.

Summer Nuclear Station. The original Report was submitted pursuant to the requirements of Technical Specification 3.4.9.3, " Reactor Coolant System - Overpressure Protection System." This revision is being submitted to amend the Action Tcken portion of the Report.

Should there be any questions, please call us at your convenience.

very truly yours,

^

O. W i r.

RJB:OWD/dwf Attachment cca . V. C. Summer K. E. Nodland T. . C. Nichols, Jr./O. W. Dixon, Jr. R. A. Stough E .' H. Crews, Jr. G. Percival E. C.; Roberts C. W. Hehl W. A. Williams, Jr. J. B. Knotts, Jr.

D. A. Nauman IEE Washington Group Managers Document Management Branch O. S. Bradham INPO Records Center C. A. Price ANI Library D. A. Lavigne NPCF J. F. Heilman File C. L. Ligon (NSRC)

OFFICIAL COPY

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Mr.. James P. O'Reilly

-SPR : 84-018

January 3, 1985

' EVENT ~ DESCRIPTION

^

On- December 4,1984, with the Plant in Mode 5, Residual Heat Removal

~

-(RHR) "

B" Train Suction Relief Valve actuated due to a Reactor Coolant

+ System (RCS) pressure transient resulting from an isolation of letdown flow.

-CAUSE OF. FAILURE

= Instrument & . Control (IEC) personnel, replacing the power supply

. drawer' to the Incore Thermocouple Separation Cabinet, inadvertently

-pinched a main power lead on the rear of the unit, shorting the lead to' ground. The short circuit ultimately resulted in the loss of 1 Inverter:XIT-5901, which>de-energized'the distribution panel providing

'powersto. Letdown Flow. Control Valve HCV-142. Loss of power.to control

. valve HCV-142 ' caused the valve ' to fail closed, isolating letdown flow M and causing the RCS' pressure transient. RHR " B" Train Suction Relief TValve actuation was' verified by the observation of the RHR discharge Ipressure indicator'IPI-600B.

L . .

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. ACTION TAKEN

The'= Operator at the controls immediately. opened Pressure Control Valves-445:A.and B to maintain the'RCS de-pressurised.

ACTION TAKEN TO PRECLUDE RECURRENCE

'The11ead on 'the 7 rear- of' the power supply drawer was replaced with a

-shorterimain; power lead to prevent pinching ~during power. supply drawer .

t removal ' and ' replacemen t. . The! Licensee also inspected the other unit

' and -verifiedL that1the installed . lead 'was short enough to preclude pinching and; subsequent grounding.

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