05000311/LER-1982-124, Forwards LER 82-124/03L-0.Detailed Event Analysis Encl

Forwards LER 82-124/03L-0.Detailed Event Analysis Encl

ML20066E309
Person / Time
Site:	Salem
Issue date:	10/27/1982
From:	Midura H Public Service Enterprise Group
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20066E314	List: 05000311/LER-1982-124, Forwards LER 82-124/03L-0.Detailed Event Analysis Encl
References
NUDOCS 8211150042
Download: ML20066E309 (3)

LER-2082-124, Forwards LER 82-124/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3112082124R00 - NRC Website

text

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Public Service Electric and Gas Company P.O. Box E Hancocks Bridge, New Jersey 08038 Salem Generating Station October 27, 1982 Mr. R. C. Haynes Regional Administrator USNRC Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Haynes:

LICENSE NO. DPR-75 DOCKET NO. 50-311 REPORTABLE OCCURRENCE 82-124/03L Pursuant to the requirements of Salem Generating Station Unit No. 2, Technical Specifications, Section 6.9.1.9.b, we are submitting Licensee Event Report for Reportable Occurrence 82-124/03L. This report is required within thirty (30) days of the occurrence.

Sincerely yours, H. J. Midura General Manager -

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Report Number: 82-124/03L Report Dat.e: 10-27-82 Occurrence Date: 10-11-82 Facility: Salem Generating Station, Unit 2 Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Reactor Coolant Loops - Inoperable.

This report was initiated by Incident Report 82-348.

CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 - Rx Power 82% - Unit Load 900 MWe.

DESCRIPTION OF OCCURRENCE:

At 0849 hours0.00983 days <br />0.236 hours <br />0.0014 weeks <br />3.230445e-4 months <br />, October 11, 1982, due to underfrequency signals on the Nos. 2F and 2H Group Buses, a reactor trip occurred.

All reactor coolant pumps (RCP's) tripped automatically, and natural circulation heat removal was commenced. Following the reactor trip, the plant was in Mode 3 of operation. With no pumps operable, Technical Specification Action Statements 3.4.1.2.a and b were entered. Prompt notification to the NRC was performed at 0853 hours0.00987 days <br />0.237 hours <br />0.00141 weeks <br />3.245665e-4 months <br />, in accordance with Emergency Procedure EPI-1. At 0927 hours0.0107 days <br />0.258 hours <br />0.00153 weeks <br />3.527235e-4 months <br />, No. 21 RCP was started and Action Statement 3.4.1.2.b was terminated. Since less than two reactor coolant loops were operable, however, Action Statement 3.4.1.2.a remained in effect. No change in reactor coolant boron concentration cccurred during the incident. '

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The underfrequency signals resulted from the failure of the No. 2A Diesel Generator local annunciator power supply. AC noise originating in the power supply was fed back to the underfrequency relays via the No. 2AADC Bus. Similar failures of this type of power supply have been observed on an isolated basis.

ANALYSIS OF OCCURRENCE:

In mode 3 operation, a single reactor coolant loop provides sufficient heat removal capability for removing decay heat; single failure considerations require that two loops be operable. Operation of one RCP provides adequate flow to ensure mixing, prevent stratification and produce gradual reactivity changes during boron concentration changes. All RCP's may be de-energized for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> provided that the core outlet temperature is maintained at least 10 F below saturation temperature.

LER

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82-124/03L . ..

s ANALYSIS OF OCCURRENCE: (continued) i l

Since flow was restored within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, and no excessive core outlet temperatures were involved, the occurrence constituted no risk to the health or safety of the public. The event involved operation in a degraded mode permitted by a limiting condition for operation and is reportable in accordance with Technical Specification 6.9.1.9.b.

Action Statement 3.4.1.2.b requires:

With no reactor coolant loop in operation, suspend all operations involving a reduction in boron concentration of the Reactor Coolant System and immediately initiate corrective action to return the required loop to operation.

Action Statement 3.4.1.2.a requires:

l With less than two reactor coolant loops operable, restore two loops to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

CORRECTIVE ACTION:

As noted, no reduction in boron concentration occurred and coolant flow was restored, in compliance with the action statements. No. 23 i

RCP was started at 0937 hours0.0108 days <br />0.26 hours <br />0.00155 weeks <br />3.565285e-4 months <br />, October 11, 1982, and Action Statement 3.4.1.2.a was terminated. The failed power supply was replaced and no further noise problems have been noted. Design Change Request 2SC-1060 has been submitted to isolate the underfrequency relays from this type of noise problem. In view of the isolated nature of the power supply failure, no further corrective action was deemed necessary.

l FAILURE DATA:

The Riley Co.

Panalarm Power Supply '

Part No. 75-PCD-25 i

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j Prepared By R. Frahm M/ <y ~

9. -

General Manager -

}/ Salem Operations SORC Meeting No. 82-96 i

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