ML20138C492
| ML20138C492 | |
| Person / Time | |
|---|---|
| Issue date: | 12/03/1985 |
| From: | Berkow H Office of Nuclear Reactor Regulation |
| To: | Rohe E WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| Shared Package | |
| ML20138C496 | List: |
| References | |
| NUDOCS 8512130031 | |
| Download: ML20138C492 (1) | |
Text
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December 3, 1985 Mr. E. P. Rahe, Jr. , Manager Nuclear Safety Department Westinghouse Electric Corporation Box 355 4 Pittsburgh, Pennsylvania 15230 i
Dear Mr. Rahe:
?
SUBJECT:
LICENSING TOPICAL REPORT WCAP-10395, " STATISTICAL EVALUATION OF LOCA HEAT SOURCE UNCERTAINTIES"
- We have completed our review of the subject topical report submitted by the Westinghouse Electric Corporation by letter dated February 21, 1984. We find the report to be unacceptable for referencing in license applications to the extent specified and under the limitations delineated in the report and the associated NRC evaluation, which is enclosed.
The purpose of the report is to justify a reduction in conservatism required by the technical specifications of operating plants for determination of r
< plant operating peaking factors. Justification for the modifications is ;
incomplete. Westinghouse evaluated the conservatism of 5 parameters, but did i not evaluate other factors affecting ECCS evaluation model uncertainty.
These omissions include the accuracy of the computer codes themselves as well as the interrelationship of the parameters (covariance).
The staff has described the necessary elements for reducing the conservatism in LOCA calculations in SECY-83-472. The evaluations in WCAP-10395 provide an important milestone in following the path outlined by the staff; however, as noted above, important considerations are lacking. We understand that Westinghouse will be submitting information in the near future which is intended to address the missing elements. These were discussed with Westinghouse in a meeting October 9, 1984. Since the methodology is being modified, we conclude that staff resources would be utilized more efficiently by waiting for the new submittal from Westinghouse rather than continuing
- review of WCAP-10395.
DISTRIBUTION: Sincerely, ,
Estrt M He %DTondi S$PD^Rdg
- a WJensen PDR MHodges DCS RLobel Original signed by l 'PNoonan Herbert N. Berkow, Director HBernard Standardization and Special HBerkow Projects Directorate l RDiggs Division of PWR Licensing-B ,
Enclosure:
As stated
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- *s.,.....) December 3, 1985 Mr. E. P. Rahe, Jr., Manager
. Nuclear Safety Department Westinghouse Electric Corporation Box 355 Pittsburgh, Pennsylvania 15230
Dear Mr. Rahe:
I
SUBJECT:
LICENSING TOPICAL REPORT WCAP-10395, " STATISTICAL EVALUATION OF f
LOCA HEAT SOURCE UNCERTAINTIES" We have completed our review of the subject topical report submitted by the Westinghouse Electric Corporation by letter dated February 21, 1984. We
[ find the report to be unacceptable for referencing in license applications to the extent specified and under the limitations delineated in the report and the associated NRC evaluation, which is enclosed.
The purpose of the report is to justify a reduction in conservatism required
, by the technical specifications of operating plants for determination of plant operating peaking factors. Justification for the modifications is incomplete. Westinghouse evaluated the conservatism of 5 parameters, but did not evaluate other factors affecting ECCS evaluation model uncertainty.
These omissions include the accuracy of the computer codes themselves as well as the interrelationship of the parameters (covariance).
- The staff has described the necessary elements for reducing the conservatism
, in LOCA calculations in SECY-83-472. The evaluations in WCAP-10395 provide an important milestone in following the path outlined by the staff; however, as noted above, important considerations are lacking. We understand that Westinghouse will be submitting information in the near future which is intended to address the missing elements. These were discussed with Westinghouse in a meeting October 9, 1984. Since the methodology is being
, r modified, we conclude that staff resources would be utilized more efficiently by waiting for the new submittal from Westinghouse rather than continuing review of WCAP-10395.
Sincerely, l / w H rbert N. Berkow, Director Standardization and Special i Projects Directorate Division of PWR Licensing-B
Enclosure:
As stated l
\
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