ML19344D053
| ML19344D053 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 02/08/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Bryan J UNION ELECTRIC CO. |
| References | |
| NUDOCS 8003110147 | |
| Download: ML19344D053 (1) | |
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?*'g UNITED STATES NUCLEAR REGULATORY COMMISSION g
-r REGION lli g
~8 799 ROOSEVELT ROAO
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GLEN ELLYN,ILLINOls 6o137 FEB 8 580 N cket No. 50-483
'wket No. 50-486 Union Electric Company ATTN:
Mr. John K. Bryan Vice President - Nuclear P. O. Box 149 St. Louis, MO 63166 Gentlemen:
The enclosed IE Bulletin No. 80-04, is forwarded for action. A written response is required.
If you desire additional information regarding this matter, please contact this office.
Cincerely, 0_mb h k
[ James G. Kep k r %
Director
Enclosure:
IE Bulletin No. 80-04 cc w/ encl:
Mr. W. H. Weber, Manager, Nuclea-Construction Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Region I & IV l
Ms. K. Drey Mr. Ronald Fluegge, Utility Division, Missouri Public j
Service Commission 8003110 M 7'
UNITED STATES SSINS No.:
6820 ffJCLEAR REGULATORY COMMISSION Accessions No.:
0FFICE OF INSPECTION AND ENFORCEMENT 7910250504 WASHINGTON, D.C.
20555 February 8, 1980 IE Bulletin No. 80-04 ANALYSIS OF A PHR ftAIN STEAM LINE BREAK UITH CONTINUED FEED'JATER ADDITION Description of Circunstances:
Virginia Electric and Power Co. submitted a recort to the Nuclear Regulatory Comission de ced September 7,1979 that identified a deficiency in the original analysis of containment pressurization as a result of reanalysis of stean line break for North 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 tt.:
- team generator that had experienced the steam line break, containment design pres.
e would be exceeded in approximately 10 minutes.
The long term blowdown of the water supplied under runout conditions by the auxiliary feedwater system had not been considered in the earlier analysis.
On October 1,1979, the foregoing information was provided to all holders of operating 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 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, Maine Yankee Atonic Power Company inforned the NRC of an error in the main stean line break analysis for the Maine Yankee plant.
During a review of the main 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 pressu e reactor trip signal. Reanalysis of the event shows the opening of the startup valve and 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:
ANO h
No. of es: