05000311/LER-1981-071-03, /03X-1:on 810723,24 & 25,constant Speed Drive 22 Breaker Tripped from Unidentified Cause.Investigation Underway.Constant Speed Drive 21 Manually Closed

/03X-1:on 810723,24 & 25,constant Speed Drive 22 Breaker Tripped from Unidentified Cause.Investigation Underway.Constant Speed Drive 21 Manually Closed

ML20010E825
Person / Time
Site:	Salem
Issue date:	08/21/1981
From:	Dickey F Public Service Enterprise Group
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20010E823	List: 05000311/LER-1981-071-03, /03X-1:on 810723,24 & 25,constant Speed Drive 22 Breaker Tripped from Unidentified Cause.Investigation Underway.Constant Speed Drive 21 Manually Closed 05000311/LER-1981-072-03, /03X-1:on 810723,discovered That Logic a Switch in Position 1 Did Not Function Properly in Mode Blocks Inhibit & Not Inhibited.Caused by Failure of Universal Board 0156. Board Replaced 05000311/LER-1981-073-03, /03X-1:on 810724,operator Noticed That Battery Charger 2C1 Had Tripped.Upon Resetting,Breaker Tripped Again.Caused by Difference Between Battery Voltage & Battery Charger Voltage Setting.Personnel Instructed 05000311/LER-1981-074-03, /03X-1:on 810725,temp Average Was Less than Required Lower Limit of 541 F During Controlled Rapid Power Reduction.Caused by Operational Transient.Temp Average Restored ML20010E822
References
LER-81-071-03X, LER-81-71-3X, NUDOCS 8109080299
Download: ML20010E825 (3)

LER-1981-071, /03X-1:on 810723,24 & 25,constant Speed Drive 22 Breaker Tripped from Unidentified Cause.Investigation Underway.Constant Speed Drive 21 Manually Closed

Event date:
Report date:
3111981071R03 - NRC Website

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Frank Dickey 609-935-5100 8109080299 810826 PHONE.

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Report Number:

81-71/03X-1 Report Date:

8-21-81 Occurrence Date:

7-23-81, 7-24-81 and 7-25-81 Facility:

Salem Generating Station, Unit 2 Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 1DENTIFICATION OF OCCURRENCE:

Electrical Distribution Syste'm - No. 22 CSD Breaker - Unidentified Trips.

This report was initi?ted by Incident Reports81-271, 81-272,81-276, 81-281 and 81-287.

CONDITIONS PRIOR TO OCCURRENCE:

7-23-81 Mode 1 - Rx Power 21% - Unit Load 160 MWe 7-23-81 Mode 1 - Rx Power 25% - Unit Load 200 MWe 7-24-81 Mode 1 - Rx Power 48% - Unit Load 440 MWe 7-24-81 Mode 1 - Rx Power 46% - Unit Load 440 MWe 7-25-81 Mode 2 - Rx Power 0% - Unit Load 0 MWe DESCRIPTION OF OCCURRENCE:

On five separate occasions on July 23, July 24, and July 25, 1981, No. 22 CSD breaker tripped from an unidentified cause.

There were no indicating flags showing on the relays.

No. 21 CSD breaker was closed manually.

Action statement 3.8.2.1.a was entered at 1614 and 1803 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.860415e-4 months <br />, July 23, 1211 and 1805 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.868025e-4 months <br />, July 24, and 1624 hours0.0188 days <br />0.451 hours <br />0.00269 weeks <br />6.17932e-4 months <br />, July 25, 1981.

This occurrence constituted operation in a degraded mode in accord-ance with technical specification 6.9.1.9.b.

DESIGNATION OF APP 7 RENT CAUSE OF OCCURRENCE:

The cause of the breaker trips is still undetermined.

It is suspected that the cause of this, and possibly other problems, is in the safe-guards equipment cabinet (SEC).

The entire chassis of the SEC has been changed several times with no positive results.

Numerous tests, investigations, and manufacturer 6 consultations were conducted.

At the date of this report, the possibility of a signal being induced into the circuit by the No. 22 primary water make-up pump, modifying the 15 volt logic voltage, is being investigated.

ANALYSIS OF OCCURRENCE:

Technical specification 3.8.2.1.a requires:

With less than the stated complement of A.C. busses operable or energized, restore the inoperable busses to operable and energized status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least hot standby within.the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

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LER 81-71/03X-1.

CgRRECTIVE ACTION:

The cause of the breaker trips is still under investigation.

The imn.ediate action in each of the five occurrences was to manually cl'>se the No. 21 CSD breaker.

At 1624 and 1805 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.868025e-4 months <br />, July 23, 1;22 and 1813 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.898465e-4 months <br />, July 24, and 1625 hours0.0188 days <br />0.451 hours <br />0.00269 weeks <br />6.183125e-4 months <br />, July 25, 1981, respectively, action statement 3.8.2.1.a was terminated.

A supplemental report will be issuea when the investigation is completed.

FAILURE DATA:

Not Applicable

'//(h[dw Prepared By F.

Dickey Manager - Salem Generating Station SORC Meeting No.

81-74