ML19296C210
| ML19296C210 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 02/08/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 8002250394 | |
| Download: ML19296C210 (1) | |
Text
b pu ar ceq'o UNITED STATES 8 'y
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NUCLEAR REGULATORY COMMISSION 5.'
. p HEGION V 4
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1990 N. CALIFORNI A BOULEVARD 6"
SUITE 202, WALNUT CREEK PLAZA h,
WALNUT CREEK, CALIFOHNIA 94596 February 8,1980 Docket flos. 50-528 50-529 50-530 Arizona Public Service Company P. O. Box 2166 Phoenix, Arizona 85036 Attention:
Mr. E. E. Van Brunt, Jr.
Vice President, Construction Projects G entlemen:
The enclosed IE Bulletin No. 80-04, is forwarded to you for information.
No written response is required.
If you desire additional infonnation regarding this matter, please contact this office.
Sincerely, LY > o20U R. H. Engelken Director
Enclosure:
IE Bulletin fio. 80-04 cc w/ enclosure:
F. W. Hartley, APS 8002250 3 }
UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMf!!SSION Accessions No.:
OFFICE OF INSPECTION AND ENFORCE'1ENT 7910250504 WASHIf:GTON, D.C.
20555 February 8, 1980 IE Bulletin No. 80-04 ANALYSIS OF A P'c!R ftAIM STEAf1 LINE BREAK tlITH CONTINUED FEED'1ATER ADDITION Description of Circunstances:
Virginia Electric and Power Co. submitted a report to the Nuclear Regulatory Comission dated September 7,1979 that identified a deficiency in the original analysis of containment nressurization as a result of reanalysis of steam line break for North Anna Power Station, Units 3 and 4.
Stone and !!ebster Engineering Cornaration performed a reanalysis of' centainment pressure following a main stean 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 pressure would be exceeded in approximately 10 minutes.
The long torn blowdown of the water supplied under runout conditions by the auxiliary feedwa,er system had not been considered in the earlier analysis.
On October 1,1979, the foregoing infornation was provided to all holders of ooerating licenses and construction permits in IE Information Notice No. 79-24.
The Palisades facility did an accident analysis review pursuant to the information in the notice and discovered that with offsite oow, r available, the condensate purps would feed the affected generator at an excessive rate.
This excessive feed was not considered in the analysis for the stean line break accident.
On January 30, 1980,!!aine Yankee Atonic Power Company informed the NRC of an error in the main stean line break analysis for the !!aine Yankee plant.
During a review of the rain 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 renain positioned "as is" during the transient.
In reality, the startup feedwater control valves will rano to 801 full open due to an override signal resultino from the lou steam generator pressure reactor trip signal.
Reanalysis of the event shows the opening of the startup valve and associated high feedwater addition to the affected stean generator would cause a raoid reactor cooldown and resultant return-to-power, a condition cutside the plant design basis.
Actions to be Taken by the Licensee-For all pressurized water power rea reactors listed in Enclosure 1:
DUPLICATE DOCUMENT 1.
Review the containment pressurc Entire docun ent previously potential for containment overp entered inco system under:
ANO No. of pages: