05000272/LER-1981-107, Forwards LER 81-107/03X-2.Detailed Event Analysis Encl

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Forwards LER 81-107/03X-2.Detailed Event Analysis Encl
ML20058D251
Person / Time
Site: Salem 
Issue date: 07/14/1982
From: Midura H
Public Service Enterprise Group
To: Haynes R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20058D255 List:
References
NUDOCS 8207270060
Download: ML20058D251 (4)
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LER-1981-107, Forwards LER 81-107/03X-2.Detailed Event Analysis Encl
Event date:
Report date:
2721981107R00 - NRC Website
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' O PSIEG Public Service Electric and Gas Company P.O. Box E Hancocks Br.dge, New Jersey 08038 Salem Generating Station July 14, 1982 i

Mr.

R. C. Haynes Regional Administrator USNRC Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 Dear Mr. Haynes LICENSE NO. DPR-70 DOCKET NO. 50-272 REPORTABLE OCCURRENCE 81-107/03X-2 SUPPLEMENTAL REPORT Pursuant to the requirements of Salem Generating Station Unit No. 1 Technical Specifications, Section 6.9.1.9.b, we are submitting supplemental Licensee Event Report for Reportable Occurrence 81-107/03X-2.

Sincerely yours, l/.

f**

H. J. Midura General Manager -

Salem Operations RH:k CC:

Distribution 8207270060 820714 PDR ADOCK 05000272 S

PDR The Energy People f5

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Report Number:

81-107/03X-2 07-14-82 Report Date:

Occurrence Date:

10-29-81 Facility:

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

Inadvertent Safety Injection.

This report was initiated by Incident Reports81-432, 81-433 and 81-434.

CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 - Rx Power 99% - Unit Load 1040 MWe.

DESCRIPTION OF OCCURRENCE:

On October 29, 1981, during normal operations, an inadvertent safety injection occurred after a reactor trip due to loss of the vital bus lA inverter.

The 1A inverter was declared inoperable and Action Statement 3.8.2.1 was entered at 1343 hours0.0155 days <br />0.373 hours <br />0.00222 weeks <br />5.110115e-4 months <br />.

During subsequent recovery actions the boron injection tank (BIT) and the No. 11 and No. 12 boric acid storage tanks (BAST) were diluted below Technical Specifications.

The BIT and BASTS were declared inoperable and Action Statemente 3.5.4.1.b and 3.1.2.8.a(2), respectively, were entered at 1358 hours0.0157 days <br />0.377 hours <br />0.00225 weeks <br />5.16719e-4 months <br />, due to the BIT and BAST dilutions.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The safety injection was caused by high steam flow indications due to loss of vital bus lA and low-low Tavg on two loops.

The loss of the 1A inverter was associated with replacing the cabinet fan unit fuses.

A voltage transient was induced into the inverter control wiring causing the inverter L, trip off line.

The cause of the Boric Acid System dilution was due to the Control Operator failing to follow proper procedures.

Instead of draining the BIT, after the injection, and refilling it from the BAST, the operator recirculated the unborated water in the BIT into the BAST, diluting the boron concentration in the entire system to below specification.

a

LER 81-107/03X-2..

ANALYSIS OF OCCURRENCE:

The unit was designed for 50 safety injection transients.

This safety injection transient was No. 14.

It was of less severity than the design basis transient, and, therefore, had no detrimental effect on the unit, so operation may safely continue.

Technical Specification 3.8.2.1 requires:

With less than the above complement of A.C. busses operable, restore the inoperable bus to operable 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 />.

Technical Specification 3.5.4.1.b requires:

With the boron injection tank inoperable, restore the tank to operable status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or be in hot standby and borated to a shutdown margin equivalent to 1% delta K/K at 200 degrees Fahrenheit within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />; restore the tank to operable status within the next 7 days 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 />.

Technical Specification 3.1.2.8.a(2) requires:

With the Boric Acid Storage System inoperable, restore the storage system 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 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 borated to a shutdown margin equivalent to at least 1% delta K/K at 200 degrees Fahrenheit; restore the Boric Acid Storage System to operable status within the next 7 days or be in cold shutdown within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

CORRECTIVE ACTION

The 1A vital instrument bus was removed from the inverter and connected to the alternate Solatron power source at 1353 hours0.0157 days <br />0.376 hours <br />0.00224 weeks <br />5.148165e-4 months <br />.

It was initially logged that Action Statement 3.8.2.1 was terminated at that time.

However, it was actually not termin-ated until after the inverter fuses had been replaced and the inverter was back in service.

Boric acid was added to the BIT and the concentration tested safisfactorily.

The BIT was declared operable and at 0215 h?nrs, October 30, 1981 Action Statement 3.5.4.1.b was terminated.

Boric acid was added to the two BASTS and the concentration tested satisfactorily.

BASTS No. 11 and No. 12 were declared operaLit und Action Statement 3.1.2.8.a(2) was terminated at 0430 hours0.00498 days <br />0.119 hours <br />7.109788e-4 weeks <br />1.63615e-4 months <br />, October 30, 1981.

LER 81-107/03X-2..

CORREC_TIVE ACTION:The inverter cabinet fan power cable was rerouted within the cabinet to preclude any interaction with the inverter control wiring. Design Change Request (DCR) lET-1352, installed electro-magnetic filters, circuit breakers, and improved wiring.

Testing has shown that the electromagnetic noise produced by energizing the fan, has been effectively reduced.

The Control Operator was counseled on proper BIT refilling procedures and a memo was written to all Senior Shift Super-visors detailing the sequence of events and consequences of a loss of vital bus for dissemination to all shift operating personnel.

FAILURE DATA:

Garret Corporation Inverter Model 524038-1 1

Prepared By R. Heller

/

h hb W General Manager -

Salem Operations SORC Meeting No.

82-68 l

4

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