05000312/LER-1981-034, Forwards LER 81-034/03L-0.Detailed Event Analysis Also Submitted

Forwards LER 81-034/03L-0.Detailed Event Analysis Also Submitted

ML20009D675
Person / Time
Site:	Rancho Seco
Issue date:	07/07/1981
From:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20009D676	List: 05000312/LER-1981-034, Forwards LER 81-034/03L-0.Detailed Event Analysis Also Submitted 05000312/LER-1981-034-03, /03L-0:on 810619,switchyard Voltage Decreased W/ Reactor Shutdown.Caused by High Local Electrical Demand. Direct Indication of Switchyard Voltage & Alarm to Be Installed in Control Room & Safety Analysis to Be Updated
References
NUDOCS 8107240264
Download: ML20009D675 (1)

LER-1981-034, Forwards LER 81-034/03L-0.Detailed Event Analysis Also Submitted

Event date:
Report date:
3121981034R00 - NRC Website

text

3

&suun SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452-3211 [I

/[j<

.gfi July 7, 1981 n

hf g +SO d

S ng t G V..x 3 %.?

C@-

j!N-R H ENGELKEN, DIRECTOR p[gy~ '

)

REGION V 0FFICE OF ltJSPECTION & ENFORCEMENT

\\

U S NUCLEAR REGULATORY COMMISSION p' 4(

g

{

1990 N CALIFORNIA BLVD 2

WALNUT CREEK PLAZA SUITE 202 WALNUT CREEK CA 94596

' + - -

n 'h 0%s lL. __l

=

FC 5

4.*

A 4'

OPERATING LICENSE DPR-54

\\ /

Ah DOCKET NO. 50-312 REPORTABLE OCCURRENCE 81-34 iTTE9 '

In accordance with Technical Specification Section 6.9.4.2.b, the Sacramento Municipal Utility District hereby submits a thirty-day report of Reportable Occurrence 81-34.

On June 19, 1981, with the reactor shutdown, voltace in the switchyard decreased to 207KV due to high demand for electricty in the area.

The diesel generators were started and used to supply power to the NSS busses. This requi red shutting down the reactor coolant pumps and operating in the decay heat mode.

Shutdown was prolonged for about six hours.

SMUD has previously submitted to the NRC a safety analysis dealing with degraded switchyard voltage.

This analysis assumed a minimum voltage of 214KV available to the NSS busses.

Since available voltage from the diesels was adequate, there was no violation of the safety analysis.

The safety analysis will, however, be updated to reflect actual switch-yard voltages encountered.

An alarm and voltage indication will be installed in the control room, so that in the future, operators will be able to monitor vcitage directly, and will transfer the NSS busses to the diesel generators earlier.

There were no transients or power reductions associated with this event.

L

}aE U wl

/

r ohn

. Mattimoe

?

Assistant General Manager and Chief Engineer 8107240264 810707 PDR ADOCK 05000312 3

PDR

, MIPC (3), EPRI-NSAC AN ELECTRIC SYSTEM iEPVING Y0rt TH4N SCO

.00 IN Int rt E A R T OF cat!T