05000312/LER-1980-044, Forwards LER 80-044/01T-0

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Forwards LER 80-044/01T-0
ML20148J527
Person / Time
Site: Rancho Seco
Issue date: 11/17/1980
From: Bossenmaier W
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20148J529 List:
References
NUDOCS 8011240368
Download: ML20148J527 (2)


LER-1980-044, Forwards LER 80-044/01T-0
Event date:
Report date:
3121980044R00 - NRC Website

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T SACRAMENTO MUfd!CIPA,Q.

. DISTRICT O 6201 5 Street. Box 15830, Sacramento. California 95813; (916) 452 3211

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ggmyrc cis.ne ogW.FJ LMT November 17,.1980

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p 21 P:4 3 22 Mr.1R. H.'Engelken, Director-Region V Of fice td rMsgec,t ion & Enforcement-

'/h ydehmission U.S.Nuc1B3Efh(bGiaBoulevard!

dj 1990 North Calif

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. Walnut Creek Plaza, Suite 202 Walnut. Creek,-CA 94396 Re: Operating License DPR-54 Docket No. 50-312 Reportable Occurrence 80-44

Dear Mr. Engelken:

In accordance with Technical Specifications. for Rancho Seco Nuclear Generating Station --Section 6.9.4.1(1), and Regulatory Guide 1.16,. Revision 4, Section C.2.a(9), the Sacramento Municipal Utility District is hereby submit-

. ting a-fourteen-day followup report to the reportable occurrence which was initially reported to Mr. G. Zwetzig of your' of fice on October 31, 1980, and by a confirmation. letter on November;3, 1980.

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'l & E Bulletin 79-01B, Environmental Qualification of Class IE

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Equipment, required an extensive review of the elect rical. components. utilized l

In. systems required to mitigate the consequences of an accident (i.e. LOCA l

and HELB both inside and outside of con'ainment),

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As a result of this review, it was' determined that no qualification documentation is available for the pressure switches utilized in the main 3

steam system.

The pressure switches are located inside the containment. The re are a total of eight switches, four on each steam generator outlet line.

l The pressure switches initiate isolation of the steam generator from the main feedwater following a low pressure indication (Main Steam Line failure Logic).

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The District is presently designing a new system which will incorporate Main Steam Line Failure Logic. The new system is required as a i

result of NUREG 0660.

The new system will be designed with components meeting all of the required quali ficat ions. Either the new system will be installed I

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and operat ional cr the exist ing swi tches will be replaced by June 30, 1982.

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To provide justification for interim operation. District engineers l

have reviewed the design of the circuit associated with the switches.

The design review concluded that the two credible f ailure modes for the switch, either a short 'or a ground, would not prevent _thc A nuit f.r.oag erfo ming its IHIS DOCUMENT CONTMNS POOR: QUAUTY PAGESj.

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l Mr. R. H..Engelken

.2-November 17, 1980 intended function.. A third f ailure mode, specifically an open circuit, i s not considered a credible failure mode f rom an environmental qualification standpoint.

Since no credible failure mode, i nduced by a harsh environment, will prevent the circuit from performing its intended function, continued Interim operation is justifiable.

The pressure switches, for which the District has been unable to obtain any qualification documentation, are manufactured by Meletron

- Corporatlon.

Respectfully Submitted, I

bA A ML6t(41.u p W. S. Bossenmaier Acting General Manager JJM:HH:rm cs: Director, MIPC (3)

Director, It,E (40) i J

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