ML19290E425
| ML19290E425 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 02/08/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Linder F DAIRYLAND POWER COOPERATIVE |
| References | |
| NUDOCS 8003110120 | |
| Download: ML19290E425 (1) | |
Text
'
'o UNITED STATES l ),,
NUCLEAR REGUL ATORY COMMISSION
~
g r
REGION 111 o
799 ROOSEVELT ROAD o
GLEN ELLYN. ILLINOls 60137 FEB b iggo Docket No. 50-409 Dairyland Power Cooperative ATTN:
Mr. F. W. Linder General Manager 2615 East Avenue - South La Crosse, WI 54601 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.
Sincerely, f' s h k '
vJames G. Kepp er Director
Enclosure:
IE Bulletin No. 80-04 cc w/ encl:
Mr. R. E. Shimshak, Plant Superintendent Centra? Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. John J. Duffy, Chief Boiler Inspector, Department of Industry, Labor and Human Relaticns 12.6 8003110
U?lITED STATES SSINS t;o.:
6820 HUCLEAR REGULATORY COMMISSION Accessions No.:
0FFICE OF INSPECTION AND ENFORCEMENT 7910253504 WASHINGTON, D.C.
20555 February 8, 1980 IE Bulletin No. 80-04 ANALYSIS OF A PWR MAIN STEAM LINE BREAK L'ITH CONTINUED FEEDUATER ADDITION Description of Circunstances:
Virginia Electric and Power Co. subnitted a recort to the Nuclear 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 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 the stean generator that had experienced the steam line break, containnent design pressure would be exceeded in approximately 10 minutes. The long tern 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 foregcing information was provided to all holders of orerating licenses and constructio-3ermits in IE Information flotice No. 79-24.
The Palisades facility did an acci ant 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 stean line break accident.
On January 30, 1980, flaine Yankee Atomic Power Company inforned the NRC of an error in the main steam line break analysis for the !1aine 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 resulting from the low 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 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:
~71/0250EdY xNo h
No. of pages: