ML20151L313
| ML20151L313 | |
| Person / Time | |
|---|---|
| Site: | 05000601 |
| Issue date: | 04/14/1988 |
| From: | Kenyon T Office of Nuclear Reactor Regulation |
| To: | Johnson W WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 8804220016 | |
| Download: ML20151L313 (4) | |
Text
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April 14, 1988 Docket No. 50-601 Mr. W. J. Johnson Nuclear Safety Department Westinghouse Electric Corporation Water Reactor Division Box 355 Pittsburgh, Pennsylvania 15230
Dear Mr. Johnson:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON RESAR SP/90 As a result of our review of the RESAR SP/90 application concerning radiological consequences of design basis accident, we require additional information in order to complete our review. Enclosed is review question Q 470.1.
Please respond to this request within 30 days of the date of this letter.
If you have any questions regarding this matter, call me at (301) 492-1120.
Sincerely, original signed by Thomas J. Kenyon, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Regulation
Enclosure:
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Docket No. 50-601 Mr. W. J. Johnson Nuclear Safety Department Westinghouse Electric Corporation Water Reactor Division Box 355 Pittsburgh, Pennsylvania 15230
Dear Mr. Johnson:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON RESAR SP/90 As a result of our review of the RESAR SP/90 application concerning radiological consequences of design basis accident, we require additional information in order to complete our review. Enclosed is review question Q 470.1.
Please respond to this request within 30 days of the date of this letter.
If you have any questions regarding this matter, call me at (301) 492-1120.
Sincerely,
.i Thomas J.
en on, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Regulstion
Enclosure:
As stated cc: See next page l
1
Docket No. 50-601 RESAR-SP/90 cc:
Trevor Pratt Brookhaven National Labcratory Building 130 Upton, New York 11973 Mr. William Schivley Westinghouse Electric Corporation ECE-410 Mail Stop 4-08 Box 355 Pittsburgh, Pennsylvania 15230 1
i*
Request For Additional Information RESAR SP/90 470.1 Following the steam generator tube rupture at North Anna, Unit 1 on July 15, 1987, VEPC0 modified the flow resistance of the steam generator downcomers at North Anna by the addition of flow baffle plates. This modification necessitated the reanalysis of certain design basis events including rupture of a steam generator tube.
The new analysis utilized a revised Westinghouse method for calculating steam generator water mass and indicated that during the event, the water level on the secondary side could potentially f all below the top of the steam generator tubes for up to a 10-minute period at the beginning of the event.
VEPCO and Westinghouse reanalyzed the design basis steam generator tube rupture accident for Surry using the revised methods and determined that the steam generator tubes at Surry could also become uncovered even though the Surry plants were not modified by the addition of flow baffle plates. The licensee further concluded that the offsite dose consequences exceeded those calculated in the Surry updated FSAR tecause tube uncovery, combined with a tube rupture at the top of the tube bundle, could produce a direct path for fission product release without iodine positioning.
This is a potentially worse design basis accident than submitted for RESAR SP/90.
a)
Utilizing the revised method for calculating watu mass, is tube bundle uncovery possible with the RESAR SP/90 steam generator?
b)
If uncovery is possible, provide rea.ialysis of the steam generator tube rupture accident, utilizing appropriate mass flow analysis and assuming a break at the top of the tube bundle. Provide details of this analyses along with the results through to potenti?i dose impact to the public.
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