ML19290E461
| ML19290E461 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/08/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8003110300 | |
| Download: ML19290E461 (1) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION i
REGION V
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1990 N. CALIFORNIA BOULEVARD
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SUITE 202, WAt NUT CREEK PLAZA
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- ,,,e WALNUT CREE K. CALIFORNIA 94596 Febraary 8,1980 3/L Docket No. 50-ES-Sacramento Municipal Utility District P. O. Box 15330 Sacramento, California 95313 A ttention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:
The enclosed IE Bulletin No. 80-04, is foraarded for action. A written response is required.
If you desire additional infornatien regarding this matter, please contact this office.
Sincerely, w,2(G R. H. Engelken Director e
Enclosure:
IE Bulletin No. 80-04 cc w/ enclosure:
R. J. Rodriguez, SMUD 1.
G. Schwieger, SMUD 80001yoScAD
U!!ITED STATES SSINS flo.:
6820 fiUCLEAR REGULATORY COMMISSION Accessions No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250504 WASHINGTON, D.C.
20555 February 8, 1980 IE Bulletin No. 80-04 ANALYSIS OF A PWR liAIN STEA" LINE BREAK L'lTH CONTINUED FEED'1ATER ADDITION Description of Circunstances:
Virginia Electric and Power Co. submitted a recort to the fluc' ear Regulatory Comission dated September 7,1979 that identified a deficiency in the original analysis of containment pressurization as a result of reanalysis of stean line break for florth Anna Power Station, Units 3 and 4.
Stone and Webster Engineering Cornoration performed a reanalysis of centainment pressure following a main steam line break and determined that, if the auxiliary feedwater system continued to supply feedwater at runout conditions to the steam generator that had experienced the steam line break, containment design oressure would be exceeded in approximately 10 minutes. The long term blowdown of the water supplied under runout conditions by the auxiliary feedwater systen had not been considered in the earlier analysis.
On October 1,1979, the foregoing information was provided to all holders of onerating licenses and construction permits in IE Information flotice flo. 79-24.
The Palisades facility did an accident analysis review pursuant to the information in the notice and discovered that with offsite power available, the condensate pumps would feed the affected generator at an excessive rate.
This excessive feed was not considered in the analysis for the steam line break accident.
On January 30, 1980, fiaine Yankee Atonic Power Conpany inforned the flRC of an error in the main steam line break analysis for the 'iaine Yankee plant.
During a review of the nain steam line break analysis, for zero or low power at the end of core life, the licensee identified an incorrect oostulation that the startup feedwater control valves would remain positioned "as is" during the transient.
In reality, the startup feedwater control valves will rano to 80% full open due to an override signal resultina from the low steam generator pressure reactor trip signal. Reanalysis of the event shews the opening of the startup valve ano associated high feedwater addition to the affected steam generator would cause a rapid reactor cooldown and resultant return-to-power, a condition outside the plant design basis.
Actions to be Taken by the Licensee:
For all pressurized water pow reactors listed in Enclosure DUPLICATE DOCUMENT 1.
Review the containment p potential for containmen Entire document previously entered into system under:
xNo 71/0250EOV h
No. of pages: