05000206/LER-1982-001, Forwards LER 82-001/01T-0.Detailed Event Analysis Encl

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Forwards LER 82-001/01T-0.Detailed Event Analysis Encl
ML20040B494
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 01/12/1982
From: Ray H
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20040B495 List:
References
NUDOCS 8201260113
Download: ML20040B494 (4)
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LER-1982-001, Forwards LER 82-001/01T-0.Detailed Event Analysis Encl
Event date:
Report date:
2061982001R00 - NRC Website
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text

.

~2Wm Southern California Edison Company S,1 ;,,,,..

W5 S A N Ot4 0 P R E NUC L E A R G E NE H a TIN G S T A T RON P.O. fl O. 128 S A N C L E M E '* T E C A L I F OR NI A 92672 H

B. RAY y a t e, o,. g b f A f 10 r4 MANA4am (714l492 7700 January 12, 1982

/

U.

S.

Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 92596-5368 Docket No. 50-206 San Onofre - Unit 1 Attention:

fir.

R.

II. Engelken

Dear Sir:

This letter describes a reportable occurrence as defined in Section 6.9.2a (9) of Appendix A to the Provisional Operating License DPR-13 involving a potential deficiency in Sigma Lumigraph Indicators, Model 9270.

This letter constitutes both the prompt 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 14 day report for San Onofre Unit 1.

Southern California Edison Company received a letter dated December 10, 1981 (attached) from International Instruments Division, Sigma Instruments, Inc. which identified a potential problem with the Model 9270 Lumigraph Indicators installed mg at San Onofre Unit 1.

The potential deficiency was described mo as incorrectly specified resistors within indicator circuitry.

2,E The potential failure has been evaluated and the following gg has been determined:

n.-

  1. U a)

A total of forty flodel 9270 Sigma Indicators are in

@m service at San Onofre Unit 1.

They are included in the gy following system indicating circuits:

o~

ME Reactor coolant system hot leg temperature, eight (8); reactor 2&

coolant system saturation temperature, two (2); margin-to-

@- N saturation, two (2); steam generator level, six (6); condensate tank level, two (2); auxiliary feedwater pump suction and I

discharge pressures, four (4); steam generator auxiliary feedwater flow, three (3); containment pressure, three (3);

/[

recirculation pump flow, two (2); hydrazine pump flow, two (2);

hydrazine tank level, two (2); hydrazine tank nitrogen pressure, two (2); containment pressure (wide range), two (2).

l

s b)

Only the indication capability of the circuit would be lost; the alarm and control functions are not affected.

To date, no failures of this nature have occurred at San Onofre Unit 1.

c)

As indicated in the December 10 letter, failure occurs over a several year period.

d)

Continued plant operation is not in jeopardy because of the nature of this potential defect.

To correct the above deficiency with Sigma Indicators, actions are being taken to modify the circuit as described in the December 10 letter during the March, 1982 outage for all indicators noted above.

This matter is presently being evaluated on San Onofre Units 2 and 3 and the results of that review will be transmitted to you in a separate correspondence.

Sincerely, f ', W/

Enclosure cc:

U.S.

Nuclear Regulatory Commission o

Office of Management Information & Program Control; Institute of Nuclear Power Operations; L.F.

Miller - USNRC Resident Inspector - San Onofre Unit 1 i

t l

l l

1 - -

SIGMA

@. INTERNATIONAL INSTRUMENTS DIVISION 5tGM A INST RUMENTS,'INC.

OPANGE. CONNECTICUT 06477 88 MARSH HILL ROAD PHONE: (203) 795-4711 December 10, 1981 Procurecent danager douthern California Luison Co.

P.O.

box 600 Roseteac, CA. 91170 Subject.

P.O.

a 1.4 0 0 0 J 9 vated December 18, 197y Lu=igraph Indicators uear bir.

We nave ciscovered a potential problem with the Model 9270 Luci 3rapns supplied on tnis order.

The R2 resistor on the alarm unit input assembly board can overneat, and in some units, tne resistors cnange in value quite consicerably.

Inis can cause the display to malfunction.

The h2 and h6 resistors on the output card of all dual indicators can preeuce tne saae result.

Finally, on single indicators, it is the R2 resistor on the out-put card.

1he proolen is not witn toe resistor quality, per se, rather tne cooice et resistor type and construction.

iae resistors are 27 A cat - one watt - carbon composition.

They snoulu ce upgraced to 27 A ont - 3 wat t - wire wound.

lois situation nas taken several years to eviuence itself as a potential generic problea.

Thus, you will not necessarily see snort teru failures at san Onofre.

in11e tae inuicator will malfunction as a result of a enan e of t

resistar.ce, ao loss of alara (in alarm units) will occur.

4 nile Inuicatioas are one to many years of service before seeing tais possiule failure, it would oe our recommencation to replace tne ni anu a6 resistors, as inoicated above, at tae earliest pos-siale tocent.

o

. o Procureuent Manager Southern California Edison Co.

Subject:

P.O.

$130u009 Dated December 18,1979 Lumigrapn Indicators

e apelogize for tue inconvenience tnis will cause.

We stand ready to a s s 2 >.t in every possible way.

Let us know how we may help.

Very truly yours, IdIERdATIOSAL I :i S T R U M E S T S DIVISIOJ SIGMA I.i S T R'Jfir.W T S, I ti C.

r\\

^

1 r e(

Lyhch,,

q D.R.

Vice-President - Sales DRL:ams cc:

W.R.

Carls p/

darnard 6 Associates 1322o trensnaw divd.

Gardena, CA. 90249 Tel. (213)515-297d

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