ML20212B240
| ML20212B240 | |
| Person / Time | |
|---|---|
| Issue date: | 09/02/1999 |
| From: | Stephen Dembek NRC (Affiliation Not Assigned) |
| To: | Liberatori L WESTINGHOUSE OPERATING PLANTS OWNERS GROUP |
| Shared Package | |
| ML20212B246 | List: |
| References | |
| PROJECT-694 TAC-M97447, NUDOCS 9909200024 | |
| Download: ML20212B240 (3) | |
Text
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w+A N-K t UNITED STATES g
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2066H001 O '
8 September 2, 1999
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Mr. Lou Liberatori, Chairman Westinghouse Owners Group Steering Committee Indian Point Unit 2 Broadway & Bleakley Ave.
Buchanan, NY 10511 l
SUBJECT:
SAFETY EVALUATION RELATED TO TOPICAL REPORT WCAP-14696, I REVISION 1," WESTINGHOUSE OWNERS GROUP CORE DAMAGE ASSESSMENT GUIDANCE"(TAC NO. M97447)
Dear Mr. Liberatori:
By letter dated November 22,1996, the Westinghouse Owners Group (WOG) submitted i Topical Report WCAP-14696," Westinghouse Owners Group Core Damage Assessment Guidance," for NRC review. There is no proprietary version. In the topical report, a revised methodology was described that would be used by licensee emergency response organization staff for estimating the extent of core aamage that may have occurred during an accident at a Westinghouse nuclear power plant. The revised methodology is a revised calculational technique for estimating core damage which relies on real-time plant indications rather than samples of plant fluids.
The revised post-accident core damage assessment methodology in WCAP-14696 replaces j the methodology approved by the staff in 1984. The 1984 methodology was revised for two j' major reasons: (1) the current methodology relies on radionuclide samples and does not effectively support emergency response decisionmaking due to the significant time delay in obtaining and analyzing these samples using the post-accident sampling system (PASS), and (2) the methodology does not reflect the latest understanding of fission product behavior, particularly the sequence specific nature of fission product retention and hydrogen holdup in the reactor coolant system (RCS), and fission product deposition in the containment and sample lines. Also, as part of a separate request related to PASS, the WOG has requested that the time commitment for obtaining and analyzing a radionuclide sample be eliminated, thereby rendering this information potentially unavailable for use in assessing core damage. The j proposed PASS relaxations, discussed in WCAP-14986-P, will be the subject of a separate ;
staff review and letter. '
The NRC staff review of the revised guidance was initiated in early 1999 following submittal of a plant-specific application of the guidance by a lead plant, Wolf Creek Generating Station. The staff met with representatives of the WOG and the licensee on February 24,1999, to discuss a l number of comments and questions related to the revised guidance. The WOG provided formal responses to these items in a letter dated March 16,1999. Based on further review, the staff issued a request for additional information (RAl) on March 25,1999. The WOG provided responses to the RAI by letter dated April 28,1999, and a subsequent revision (Revision 1) of the topical report.
The enclosed safety evaluation approves the use of the revised guidance in WCAP-14696, i Revision 1, for core damage assessments for Westinghouse nuclear power plants. The staff i q4-l b 3 I4 a180 WrA rsaw, -
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- L. Liberatori September 2, 1999
- concludes that the revised core damage assessment guideline (CDAG) in Appendix A to WCAP-14696 provides the capability to assess the degree of core damage with a sufficient level of accuracy and timeliness to support emergency response decisionmaking. The revised guideline represents an improvement over the existing methodology. It is both simpler and more timely, and accounts for fission product and hydrogen retention / holdup in the RCS and fission product removal by containment sprays in an approximate manner. By making core damage information available earlier in an event, such that it can be used to refine dose assessments and confirm or extend initial protective action recommendations, implementation of the revised CDAG should increase the effectiveness of the emergency response organization. Based on its review, the staff finds the revised CDAG provided in WCAP-14696, Revision 1, to be an acceptable basis for meeting the NUREG-0737, ll.B.3 requirement for a core damage assessment procedure.
The NRC requests that the WOG publish an accepted version of the revised topical report within 3 months of receipt of this letter. The accepted version shallincorporate this letter and the enclosed safety evaluation between the title page and the abstract, and add an -A (designating accepted) following the report identification number (i.e., WCAP-14696-A).
If the NRC's critena or regulations change so that its conclusion in this letter, that the topical report is acceptable, is invalidated, WOG and/or the applicant referencing the topical report will be expected to revise and resubmit its respective documentation, or submit justification for the continued applicability of the topical report without revision of the respective documentation.
Sincerely,' j ORIGINAL SIGNED BY Stephen Dembek, Chief, Section 2 Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Reactor Regulation Project No. 694
Enclosure:
Safety Evaluation cc w/ encl: See next page DISTRIBUTION Central File OGC PUBLIC ACRS PDIV-2 Reading RScholl(e-mail SE)
DMcCain RPalla >
To receive a copy of this document, indicate "C" in the box OFFICE PDl%2N C PDIV-2/LA C PDIV-2/SC i NAME JDEMrb EMnF SDembek[
DATE O /2d /99 9 / A/99 [/ 0/99 3
DOCUMENT NAME: C;\WPDOCS\OwnersGroups\ Letter-WCAP14696-2. approval.wpd OFFICIAL RECORD COPY
Westinghouse Owners Group - Project No. '694 .
cc w/enci:
Mr. H. A. Sepp, Manager Regulatory and Licensing Engineering P.O. Box 355 Pittsburgh, PA 15230-0355 Mr. Andrew Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation Mail Stop ECE 5-18 P.O. Box 355 cm.ouigh, PA 15230-0355 Mr. Jack Bastin, Director Regulatory Affairs Westinghouse Electric Corporation 11921 Rockville Pike Suite 107 Rockville, MD 20852 Mr. Hank Sepp, Manager Regulatory and Licensing Engineering Westinghouse Electric Corporation PO Box 355 Pittsburgh, PA 15230-0355 Mr. Otto L. Maynard President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, Kansas 66839 Superintendent Licensing Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, Kansas 66839 l
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