ML20072Q893

Special Rept SR-91-001-00:on 910207,channel 2 of SPDS Failed & Could Not Be Restored within 7 Days.On 910214, Channel 2 of Qualified SPDS Sensor 8 Out of Svc for More than 7 Days.Channel 2 Probe Will Be Replaced

ML20072Q893
Person / Time
Site:	Waterford
Issue date:	03/18/1991
From:	Mcgaha J ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SR-91-001-00, SR-91-1, W3B5-91-0092, W3B5-91-92, NUDOCS 9103210161
Download: ML20072Q893 (4)

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W3B5-91-0092 A4.05 QA f

-March 18, 1991 U.S. Nuclear Regulatory Commission l

ATTENTION:

Document-Control Desk I

Washington, D.C.

20555

SUBJECT:

Waterford 3 SES Docket No.-50-382

-License No. NPF-38 Reportina of Special Report f

Gentlement r

Attached is Special Report Number SR-91-001-00 for Waterford Steam Electric Station Unit 3.

This Special Report is submitted per 10CFR50.36(c) (2) and Technical Specifications 3.3.3.6.

i Very truly yours, K

J.R. McGaha 4 General Manager Plant Operations JRM/WEP/rk Attachment

-cc:

Messrs. R.D. Martin G.L. Florreich J.T. Whoelock - INPO Records Center E.L. Blake-D.L. Wigginton NRC Resident Inspectors Office P

9103210161 910318 l

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9 SPECIAL rep 0RT SR 91 001 I

Qualified Safety Parameter Display System. Channel 2 Resctor Vessal Level Monitoring System, Out of Service Due To Sensor Failure.

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INTRODUCTION On February 7, 1991, Waterford Steam Electric Station Unit 3 was operating at 100% power.

Channel #2 of the Qualified Safety Parameter Display System (QSPDS) failed and could not be restored within the 7 day time period specified in Technical Specification (T.S.) 3.3.3.f The most probable root cause of the event has been classified as a sensor failure of the lleated Junction Thermocouple (IUTC), With two other sensors already out of service, the failure of IUTC # 8 brought the total number of sensors out of ser**1ce to three, of the lower five.

For each channel to be operable it must have three of five sensors operable / quadrant, f

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T.S. 3.3.3.6, Accident Monitoring Instrumentation Limiting Condition for Operation of the Technical Specifications, table 3.3 10, action 31 states t;.at "With the number of OPERABLE accident monitoring channels, less than the Required Number of Channels, either restore the system to operable status within 7 days if repairs are feasible without shutting down or prepare and submit a Special Report to the Commission pursuant to Specification 6.9,2 within 30 days following the event outlining the action taken, the cause of the inoperability and the plans and schedule for restoring the system to OPERABLE status."

SPECIAL rep 0RT SR 91 001 NARRATIVE At 0548 hours0.00634 days <br />0.152 hours <br />9.060847e-4 weeks <br />2.08514e-4 months <br /> on February 14, 1991 Vaterford Steam Electric Station Unit 3 was operating at 1001 power when Channel 2 of the Qualified Safety Parameter Display System, IUTC sensor # 8 exceeded the 7 day out of service limit per T.S. 3.3.3.6.

The purpose of the Reactor Vessei Level Monitoring System (RVLMS) is to provide instrumentation for erihancing the ability of the operator to diagnose inadequate core cooling, required by NUREG 0737 post TM1 2 Action Plan.

Troubleshooting did not determine any problems with the QSPDS Channel 2 electronics. The most probable root cause of the equipment unifunction is a failure of the RJTC probe. QSPDS Channel 2, sensors # 5 and # 7, were inoperable prior to the failure of IUTC # 8.

Therefore, three of the bottoe five sensors were out of service, making the channel inoperable.

Although one channel of RVLMS is inoperative, the other channel is operating.

There is also other instrumentation available for monitoring the core for i

inadequate core cooling, for example, Subcooled Mars n Monitoring (SHM) and the Coro Exit Thermocouples (CET). One channel of RVLMS inoperable does not create a major safety concern.

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SPECIAL REPORT l

SR 91 001 The planned corrective action is to replace the QSPDS Channel 2 IUTC probe during Refuel 4.

The work will be performed under Work Authorization 01072254. Also, a QSPDS surveillance will be performed on QSPDS channels 16 2 during Refuel 4, which will confirm satisfactory system operation.

Refuel 4 is planned to begin March 15, 1991, and corrective. actions will be completed at the end of Refuel 4, approximately May 11, 1991.

SIMILAR EVENTS NONE PLANT CONTASI f.c Brian, Plant Engineering Superintendent - (504) 464 3127 L

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