ML19323B646
| ML19323B646 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/25/1980 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Rich Smith VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| NUDOCS 8005140019 | |
| Download: ML19323B646 (3) | |
Text
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WASHINGTON. D. C. 20555 APRit
! 5 1980 Docket No. 50-271 Mr. Robert L. Smith Licensing Enginer Vermont Yankee Nuclear Power Corporation 25 Research Drive Westboro, Massachusetts 01581
Dear Mr. Smith:
SUBJECT:
EFFECT OF A DC P0iiER SUPPLY FAILURE ON ECCS PERFORMANCE It has generally been recognized that the loss of a direct current (DC) power supply could disable several energency core cooling system components and thereby could result in a limiting single failure condition for some breaks. The enclosed letter report was submitted to the NRC staff by the General Electric Cotpany to provide a definitive, generic, reference analysis of the effects of DC power supply failures on ECCS conformance calculations.
The NRC staff is reviewing the analysis which compares the peak cladding tenperatures associated with various postulated DC power supply failure (ECCS egipment availability) cases to the peak cladding temperatures for a liPCI (small break) failure and LPCI injection valve (large break) failure cases. Since the study was based on plant design information which may have been incccplete or out-of-date, some uncer-tainty exists whether the worse ECCS system availability combinations have been identified for your operating SWRs. Accordingly, in order that we may have an adequate level cf assurance that the systens com-binations assumed in the ger.eric analysis are conservative for Vermont Yankee Nuclear Power Station, we rec,uest that you confinn the conclusion of the reference study regarding the =inicum ECCS equipment availability with a DC power supply failure.
Include in your response a list of the ECCS equipment that would be available for large and small (1) recircula-tion loop discharge breaks, and (2) recirculation loop suction breaks.
Tne listing of equipment available should take into account not only DC power supply failure, but also loss of equipment due to water spillage.
Please provide a schedule for your respense within 30 days of the receipt of this letter.
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L Mr. Robert L. Smith APRIL 2 5 1980 This request for generic information was approved by GA0 under clearance nu::6er B-183225(579018); this clearax:e egires October 31, 1980.
Sincarely,
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o, Chief Oceriting Reactors Branch #3 Division of Operating Reactors
Enclosure:
General Electric Co@any letter (R. E. Engel) to USNRC (P. S.
Check), "DC Ptwer Source Failure for BWR/3 and 4," dated Neve::t>er 1, 1978.
cc w/ enclosure:
See next page j
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L Mr. Robert L. Smith APRIL 2 5 1990 cc:
Ms. J. M. Abbey John R. Stanton. Director Vermont Yankee Nuclear Power Radiation Control Agency Corporation Hazen Drive 77 Grove Street Concord, New Hampshire 03301 Rutland, Vermont 05701 John W. Stevens Mr. Louis H. Heider, Conservation Society of Vice President Southern Vermont Vermont Yankee Nuclear Power P. O. Box 256 Corporation Townshend, Vermont 05353 25 Research Drive Westboro, Massachusetts 01581 Dr. Mars Longley, Director Occupational & Radiological Health John A. Ritsher, Escuire 10 Baldwin Street Ropes & Gray Montpelier, Vermont 05602 225 Franklin Street Boston, Massachusetts 02110 New England Coalition on Nuclear Pollution Laurie Burt Hill and Dale Farm Assistant Attorney, General West Hill - Faraway Road Environrental Protection Division Putney, Vermont 05346 Attorney General's Office One Ashburton Place,19th Floor Public Service Board Boston Kassachusetts 02108 State of Vermont 120 State Street Ronald J. Wilson Montpelier, Vermont 05602 81018th Street, N. W.
Suite 802 W. P. Murphy, Plant Superintendent Washington, D. C.
20006 Vermont Yankee Nuclear Power Corporation Honorable M. Jerome Diamond P. O. Box 157 Attorney General Vernon, Vermont 05354 State of Vermont 109 State Street Mr. Charles Sheketoff Pavilion Office Building Assistant Director Montpelier, Vermont 05602 Vermont Public Interest Research Group, Inc.
Mr. J. E. Griffin, President 26 State Street Vermont Yankee Nuclear Power Montpelier, Vermont 05602 Corporation 77 Grove Street Brooks Memorial Library Rutland, Vermont 05701 224 Main Street Brattleboro, Vermont 05301
r, 1)){ (, } 9 { l d } l $ 1 j y' GENERAL 4 ELECTRIC wuCos*R eneRoy PROJECTS DIVISION GENERAL ELECTRIC COMPANY,175 CURTNER AVE., SAN JOSE, CAUFORNIA 95125 MC 682, (408) 925-1153 November 1, 1978 REE- 054 '78 MvN -410- 78 U.S. Nuclear Regulatory Commission Division of Operating Reactors Washington, D.C. 20555 Attention:
P.S. Check, Chief Reactor Safety Branch Operational Technology
Dear Mr. Check:
SUBJECT:
DC Power Source Failure For BWR/3 and 4 A recent concern expressed by members of your staff is the effect of a direct current (DC) power source failure on the currently approved 10CFR50.46 conformance calculations for operating BWR/3's and 4's.
The General Electric Company has conducted a study of this concern and has documented the results in Attachment 1 to this letter. An additional concern expressed was the lack of a peak cladding temperature (PCT) versus break area curve in the small break region which could be applied to operating BWR/3's and 4's.
This concern is also covered in Attachment 1.
The study was performed with the 1977 approved model and input changes using bounding assumptions to provide a generic result applicable to all operating BWR/3's and 4's.
The results of the study show that there is an increase in PCT for small breaks; however, the PCT remains less than 1950 F.
For large breaks, the PCT was not affected. Also, the maximum average planar linear heat generation rate (MAPLHGR) is not affected for any plant.
If you have any questions or comments, please contact R. T. Hill of my staff on (408) 925-3255.
Sincerely, BE R. E. Engel, Manager Operating Licenses I Safety and Licensing Operation Attachment cc:
F. D. Coffman R. H. W. Woods
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&I l' ut, s, b ATTACHMENT 1 DC P0k'ER SOURCE FAILURE FOR Bk'R 3 AND 4 1
DUPLICATE DOCUMENT Entire document previously entered into system under:
ANO No. of pages:
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