05000344/LER-1982-008, Forwards LER 82-008/03L-0.Detailed Event Analysis Encl

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Forwards LER 82-008/03L-0.Detailed Event Analysis Encl
ML20054L434
Person / Time
Site: Trojan File:Portland General Electric icon.png
Issue date: 06/22/1982
From: Steele R, Yundt C
PORTLAND GENERAL ELECTRIC CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20054L435 List:
References
CPY-481-82, NUDOCS 8207080120
Download: ML20054L434 (3)
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LER-1982-008, Forwards LER 82-008/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
3441982008R00 - NRC Website
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f rojan Nudear Plant CPY-481-82 P.O. Itox 4 F) p Rainier, Ore;;on 97018 (503) 55fv3713 g

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(t) l Mr. R. II. Engelken, Regional Administrator j

US Nuclear Regulatory Commission - Region V 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Do.ir Sir:

In accordance with the Trojan' Plant Operating License, Appendix A, USNRC Technical Specifications 6.9.1.9.b, attached is Licensee Event Report No.

82-08 concerning the failure of a 125-volt DC battery charger to pass its annual maintenance test as required by the Technical Specifications, paragraph 4.8.2.3.2.c.3.

This may have c uured operation in a degraded modo permitted by a limiting condition for operation, 3.8.2.3.

Sincerely, W

2 C.P.'u t

Generi anager a'

I R. L.I tecle, Manager Nuclear Projects Engineering CPY/GGB/KLN:ga Attachments c:

LER Distribution File 93.24a(Q) 8207080120 820622 PDR ADOCK 05000344 k

M REPORTABLE OCCURR124CE 1.

Report No 82-08 2.

Report Date:

June 22, 1982 3.

Occurrence Date:

April 24, 1982 1

4.

Facility: Trojan Nuclear Plant, PO Box 439, Rainier, Oregon 97048 5.

Identification of Occurrence:

One of four 125-volt DC battery chargers failed to pass the annual performance test required by Technical Specification 4.8.2.3.2.c.3.

Each battery charger is required to supply at least 197 amperes at 122 volts for a period of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />; however, during the test the out-put of charger D23 could not be increased above 180 amperes. The problem was eventually found to be a failed diode in the charger's control circuitry. As the charger had not been required to perform at this output since the previous annual test on May 5, 1981 it is impossible to determine when the failure occurred. Consequently, charger D23 may have been inoperable from the date of the last successful test.

6.

Conditions Prior to Occurrence:

The plant was in Mode 5, cold shutdown, when the annual test was performed.

7.

Description of Occurrence:

Battery chargers in the 125-volt DC system are tested during each refueling outage by performing a routine maintenance test (MP-1-14).

The purpose of this test is to verify that each charger can provide sufficient current to charge the battery for an extended period.

Technical Specification 4.8.2.3.2.c.3 defines satisfactory performance as an output of 197 amperes for a period of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

When the test was performed on April 24, 1982 the output of charger D23 could not be increased above 180 amperes. The problem was found to be a failed diode in the control circuit.

The last successful test was performed on May 5, 1981 and it is not possible to determine when during the following year the diode failed. As a result the charger may have been inoperable from the date of the last test.

Technical Specifications require a minimum of one of the two chargers be operable on each train of DC power. A review of operating records shows that on September 1, 1981 charger D23 was the only charger available on the

'A' train when its companion charger was removed from service for maintenance.

Since charger D23 may have been inoperable at that. time minimum Technical Specification requirements may rnt Inve been satisfied. This condition lasted for less thun 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> (exact times cannot be determined).

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Reportable Occurrence Page Two 8.

Designation of Apparent Cause of Occurrence:

The cause of this failure is attributed to the random failure of a diode in the charger's control circuitry. This report is submitted after the normal 30-day reporting time.

Personnel who performed the test were not aware of the potential significance of this event.

Because of this they failed to present the results to the attention of Maintenance supervisory personnel in sufficient time to submit this report within 30 days.

9.

Significance of Occurrence:

This event had no effect on plant or public safety as the redundant 125-volt DC train was available and operable.

10.

Corrective Action

Immediate corrective action was taken to replace the failed diode and to successfully perform the annual surveillance test.

The failure has been determined to be a random failure and no further corrective action is planned at this time.

To correct the late reporting of this event, Maintenance supervisory personnel have held a training session with the Maintenance electrical personnel discussing this event and the importance of prompt reporting.

In addition to the training session the Maintenance Department will review all their maintenance procedures and when necessary, change them to include specific accep-tance criteria and identify Technical Specification items. The i

method for reviewing and filing completed surveillances will be changed to ensure prompt supervisory review.

These actions will be completed by December 31. 1982.

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