ML20010H273
| ML20010H273 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 09/21/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Linder F DAIRYLAND POWER COOPERATIVE |
| References | |
| TASK-15-15, TASK-RR LSO5-81-09-055, LSO5-81-9-55, NUDOCS 8109240290 | |
| Download: ML20010H273 (5) | |
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September 22, 1981 sh' r,
Docket No. 50 le)
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/s % C 4 Mr. Frank Linder
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%y Dairyland Power Cooperative 2
2615 East Avenue South
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Lacrosse, Wisconsin 54601
Dear Mr. Linder:
SUBJECT:
LACROSSE - SEP TOPIC XV-15, INADVERTENT OPENING OF A PWR PRESSURIZER SAFETY /R LIEF VALVE OR A BWR SAFETY / RELIEF VALVE In your letter dated June 30,1981 (LAC-7637) you submitted a safety assess-ment report on the above topic. The staff has reviewed your assessment and our conclusions are presented in the enclosed safety evaluation report. Our report cocpletes this topic evaluation for the Lacrosse Boiling Water Reactor (LACBWR).
The enclosed safety evaluation will be a basic input to the integrated :,afety assessment for your facility. The assessment may be revised 1:: the future if your facility design is changed or if NRC criteria relating to chis topic are modified before the in'.ograted assessment is completed.
Sincerely, Dennis H. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing s'co4 I
Enclosure:
5 As stated eb cc w/ enclosure:
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Mr. Frare. Linder Cc Fritz Schubert, Esquire U. S. Environmental Protection Staff Attorney Agency Dairyland Power Cooperative Federal Activities Branch 2615 East Avenue South Region Y Office La Crosse, Wisconsin 54601 ATTN: Regional Radiation Repre,entative 230 South DearboTn Street O. S. Heistand, Jr., Esquire Chicago, Illinois 60604 Morgan, Lewis & Bockius I
1800 M Street, N. W.
Mr. John H. Buck Washington, D. C.
20^3L Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Comission Mr. R. E. Shimsr..k Washin2 ton, D. C.
20555 La Crosse Boiling Water Reactor Datryland Power Cooperative Dr. Lawrence R. Quarles P. O. Box 135 Kendal at Longwood, Apt. 51 Genoa, Wisconsin 54632 Kenneth Square, Pennsylvania 19348 Ms. Anne K. Morse Charles Bechhoefer, Esq., Chairman Coulsa Region Energy Coalition Atomic Safety and Licensing Board P. O. Box 1583
- d. S. Nuclear Regulatory Comission la Crosse, Wiscons.*n 54601 Washington, D. C.
20555 La Crosse Public Library Dr. George C. Anderson 800 Main Street Department of Oceanography La Crosse, Wisconsin 54601 University of Washington Seattle, Washington 98195 U. S. Nuclear Regulatory Comission Resident Inspetors Office Mr. Ralph S. Decker Rural Route #i, Box 276 Route 4, Box 1900 Genoa, Wisconsin 54632 Cambridge, Maryland 21613 T u n Chairman Thomas S. Moore Toren of Genoa Atomic Safety and Licensing Appeal Board a.ite 1 U. S. Nudear Regulatory Comission Genoa, Wisconsir 54632 Weihington, D. C.
20555 l
l Chairman, Public Service Comission I
of Wisconsin Hill Farms State Office Building Madison, Visconsin 53702 Alan S. Rosenthal, Esq., Chairman Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Mr. Frederick Milton Olsen, III 5
609 North lith Street Lacrosse, Wisconsin 54601
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4 TOPI C XV-15 INADVERTENT OPEt:ING OF A PWR PRESSURIZER SAFETY / RELIEF VALVE OR A BWR SAFETY / RELIEF VALVE LA CROSSE BOILING WhfER REACTOR I.
INTRODUCTION j
The inadvertent opening of a safety / relief valve results in a reactor coolant inventory decrease and a decreasc in reactor coolant system pressure. The LACBWR design does nct provide for safet / relief valve discharge into a suppression poo' ; therefore, valve discharge is to the containment and the 1
containment building is automatically isolated on high containment building pressure. Operator action is taken to trip the reactor. The objectis.' of this evaluation is to confirn that the plant responds to the safety / relief valve opening transient in such a way that the criteria regarding fuel damage and system pressure are met.
II. EVALUATION Three spring-loaded safety valves protect the LAC 8WR primary system from transient overpressur"zation conditions in accordance with the ASME Boiler and Pressure Vessel Code. The location of the valves in a steam line is such that an open valsa would be equivalent to a steam line break. Following opening of the valve, the turbine inlet governor valves partially close to maintain system pressure. If no manual action is taken, the reactor would trip on low reactor preisure and icw reactor water level.
Under these conditions, the low reactor water 1,evel wculd initiate the High.oressure Core Spray (HPCS). When the reactor vessel prr;sure decreases to 150 r'.ig, the Alternate Core Spray (ACS) would be activated. The combined operation of the HPCS and ACS provides long term cooling of the core.
4
2 Snall break results in the LACBWR LOCA analysis have been extrapolated from large and internediate size breaks as, discussed in Reference 1.
The adequacy of the LACBWR ECCS evaluation model was discussed in Reference 2.
This evaluation was made with respect to the requirements for analysis of blowdown phenomena, as prescribed in 10 CFR 50, Appendix K.
The LOCA results have shown that the t
WCS is adequate, even with a single failure, to prever.t fuel damage.
In addition, the licensee cas provided additional infomation to demonstrate thr.t the consequences of a stuck open relief valve are less severe tilan other types M transients (Reference 3).
In these analyses, the Critical Power Ratio (CPR) stays above 1.32 and the core remains covered.
The relief valve setpcints are a combination of 1390 and 1426 psig. Nomal primary coolant system pressure is '!300 psig. Operation of the safety valves will maintain system pressure below 110 percent of the design pressure of 1540 psia.
III. CONCLUSIONS As part of the SEP revies. of LACBWR. the inadvertent opening of a safety / relief valve was reviewed against the acceptance criteria of SRP Section 15.6.1.
Although this accident condition has not been arialyzed specifically, the plant response is bcunded by other trensients such that the criteria regarding fuel damage and system pressure are met.
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s REFErJNCES 1.
DPC Letter L AC-6705, Linder to D. Ziemann,,
SUBJECT:
nformation on Snall Break f.nalysis, dated Decerreer 20, 1979.
I 2.
NES-01 A0244, " Comparison of LACBWR ECCS ResultS to AEC Final Acceptance Criteria," December 9, 1974.
3.
NES-81A0025, " Transient Analyses for' LAC 3WR Reload Fuei" February 18, 1977.
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