05000395/LER-1983-031, Forwards LER 83-031/03L-0.Detailed Event Analysis Encl

Forwards LER 83-031/03L-0.Detailed Event Analysis Encl

ML20073R321
Person / Time
Site:	Summer
Issue date:	04/22/1983
From:	Dixon O SOUTH CAROLINA ELECTRIC & GAS CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20073R324	List: 05000395/LER-1983-031, Forwards LER 83-031/03L-0.Detailed Event Analysis Encl 05000395/LER-1983-031-03, /03L-0:on 830325,ECCS Mechanical Water Chiller XHX-001B Tripped.Caused by Intermittently Failing Valve Control Switch.Switch Repaired
References
NUDOCS 8305030627
Download: ML20073R321 (3)

LER-1983-031, Forwards LER 83-031/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3951983031R00 - NRC Website

text

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' kb SOUTH CAROLINA ELECTRIC & GAS COMPANY post oprics 7e4 COLuusiA south CAROLINA 29218 O. W. DixoN, JR.

nu$*.'d"o"$I,"[o.

April 22, 1983 mw

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~o Mr. James P. O'Reilly

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Regional Administrator U.S. Nuclear Regulatory Commission

k Region II, Suite 2900

,a 101 Marietta Street, N.W.

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Atlanta, Georgia 30303 cn cn

SUBJECT:

Virgil C. Summer Nuclear Station' Docket No. 50/395 Operating License No. NPF-12 Thirty Day Written Report LER 83-031

Dear Mr. O'Reilly:

Please find attached Licensee Event Report #83-031 for Virgil C.

Summer Nuclear Station.

This Thirty Day Report is required by Technical Specification 6.9.1.13.(b) as a result of entry into the Action Statement of Technical Specification 3.1.2.3,

" Reactivity Control Systems, Charging Pump - Shutdown," and into Action Statement (a) of Technical Specification 3.4.1.4.2,

" Reactor Coolant System, Cold Shutdown - Loops Not Filled," on March 25, 1983.

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

Ver truly ours O. W. D' on, Jr.

HCF:OWD/dwf i

Attachment cc:

V. C.

Summer G.

J. Braddick T.

C. Nichols, Jr.,/O. W. Dixon, Jr.

J.

C. Miller E.

C.

Roberts J. L. Skolds H.

N.

Cyrus J.

B.

Knotts, Jr.

Group / General Managers I&E (Washington)

O.

S. Bradham Document Management R. B.

Clary Branch C. A.

Price INPO Records Center.

A. R.

Koon NPCF D. A. Lavigne File (Lic./Eng.)

C.

L. Ligon (NSRC) 8305030627 830422 PDR ADDCK 05000395 S

PDR Te--- A L 2

t Mr. James P. O'Reilly LER No.83-031 Page Two April 22, 1983 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES On March 25, 1983, with the Plant in Mode 5, the Train "B" HVAC System Mechanical Water Chiller (XHX-001B) of the Chilled Water l

System (VU) tripped at 1750. hours.

The chiller was supplying cooling water for the Train "B" Component Cooling Water System pump motor, which was providing cooling water for the Train "B" Residual Heat Removal System heat exchangers and pump shaft seal water cooler.

Additionally, the chiller was providing cooling 1

water to the Train "B" Charging / Safety Injection pump inbe oil cooler.

The action statements of the following Technical Specifications were entered as a result of the trip condition:

i

)

Technical Specification 3.1.2.3,

" Reactivity Control System, Charging Pump - Shutdown," which-requires one (1) charging pump in the bore.'. ion flow path to be operable.

Technical Specification 3.4.1.4.2, Reactor Coolant System, Cold Shutdown - Loops Not Filled," which requires two (2) residual heat removal loops to be operable and at least one (1) loop to be in operation.

There were no adverse consequences resulting from the event as 1

I.

Train "A" of the Emergency Core Cooling Systems were aligned to the Train "A" Chiller (XHX-001A).

At 2330 hours0.027 days <br />0.647 hours <br />0.00385 weeks <br />8.86565e-4 months <br />, on March 25, i

1983, maintenance activities were completed on backup. Chiller t

(XHX-001C), and it was aligned and started on the Train "B" Chilled Water System.

These actions satisfied the Technical Specification Action Statements.

CAUSE AND CORRECTIVE ACTIONS

The Station experienced a loss of bus IDS at 1607 hours0.0186 days <br />0.446 hours <br />0.00266 weeks <br />6.114635e-4 months <br /> on-March 25, 1983, due to an inadvertent opening of breaker OCB-8892.

Subsequently, the Train "B" Solid State Protection System stripped the vital plant loads (including the Chiller, XHX-001B) and started the "B" Diesel Generator (XEG-001B).

The Chiller XHX-001 was then reloaded by the loading sequencer.

Approximately one hour and forty-three minutes later, at 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br />, Chiller XHX-001B tripped for no apparent reason.

A-common indicator light for. "high motor temperature," "high discharge I

temperature,";and "high oil temperature," located on.the local control panel was found to be energized.

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s Mr. James P. O'Reilly LER No.83-031 Page Three April 22, 1983 CAUSE AND CORRECTIVE ACTIONS Continued A post-trip investigation produced no explanations for the chiller trip.

A manufacturer's representative was procured; and on March 29, 1983, Chiller XHX-001B was restarted to determine the cause of the unexplained chiller trip on March 25, 1983.

It was discovered that the local control switch for isolation valve XVB-3126, which controls cooling water flow to the chiller, was intermittently failing, thereby preventing the valve f rom opening.

This would account for the alarm and subsequent trip of Chiller XHX-001B on March 25, 1983.

A maintenance work request has been generated to repnir the control switch.

This will be accomplished when Chiller XHX-001B is available or before startup af ter the present steam generator modification outage.

i