ML20198L485
| ML20198L485 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/30/1998 |
| From: | Scherer A SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20198L486 | List: |
| References | |
| RTR-REGGD-01.175, RTR-REGGD-1.175 NUDOCS 9901050033 | |
| Download: ML20198L485 (3) | |
Text
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5001HERN CAlliORNIA A. Edward Scherer EDISON t':"%,m An LDISON INTERNATIONAL
- Company December 30, 1998 U. S. Nuclear Regulatory. Commission Attention: Document Control Desk i
Wa:hington, D. C. 20555
Subject:
Docket Nos. 50-361 and 50-362 Request to Implement a Risk-Informed Inservice Testing Program During the Remainder of the Second Ten-Year Interval San Onofre Nuclear Generating Station Units 2 and 3
Reference:
Regulatory Guide 1.175 "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Inservice Testing," Issued August, 1998.
Gentlemen:
This letter requests NRC approval to implement a Risk-Informed Inservice Testing Program to specify pump and valve testing frequencies in lieu of the testing frequencies currently specified by the ASME Code.
Based on considerations of the quantitative and qualitative aspects of this program, implementation of this program will result in a net decrease in the probability of both core damage and large early release at San Onofre Units 2 and 3.
This request is submitted for your approval under the provisions of 10 CFR50.55a(a)(3),whichstates:
" Proposed alternatives to the requirements of paragraphs (c), (d), (e),
(f), (g), and (h) of this section or portions thereof may be used when authorized by the Director of the Office of Nuclear Reactor Regulation.
The applicant shall demonstrate that:
(1)
The proposed alternatives would provide an acceptable level of j
quality and safety, or (ii) Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality end safety."
h 9901050033 981230 PDR ADOCK 05000361 P
PDR P. O. Box 128 San Clemente, CA 92674-0128 949-368-7501 Fax 949-368-7575
Document Control Desk San Onofre Units 2 and 3 are currently in their fourth year of the second ten-year Inservice Testing interval. Both Units began the second ten-year interval on April 1,1994, and the interval will end on August 17, 2003.
San Onofre Units 2 and 3 are committed to the 1989 Edition of the ASME Code, with no addenda. to this letter is the Southern California Edison Request for Alternative Testing Frequencies - Implementation of Risk-Informed Inservice Testing at San Onofre Nuclear Generating Station, Units 2 and 3.
This riquest was prepared using the guidance of Regulatory Guide 1.175, referenced above. provides the proposed San Onofre Nuclear Generating Station Risk-Informed Inservice Testing Program.
The proposed San Onofre Risk-Informed Inservice Testing Program is based on the current Inservice Testing Program as of December 23, 1998. Changes to the Inservice Testing Program between December 23, 1998, and the NRC approval date for using the alternative testing will be addressed using the process defined in the proposed Risk-Informed Program.
For example, any valve that is added to the Program during the upcoming Cycle 10 refueling outages would continue to be tested per the prescribed test intervals in the current Program until the NRC has approved the proposed Risk-Informed Inservice Testing Program for San Onofre and the first regularly scheduled Program update can be performed.
- Although the engineering analysis was performed for components in both Units 2 and 3, Tables 2.3-1 (Comparison of Component Functions), 2.3-2 (Component Categorization and Expert Panel Basis), and 3.2-1 (Inservice Testing Program Changes) of enclosure 2 list only Unit 2 components and components common to both units.
The Unit 2 component functions mirror the Unit 3 component functions, so the tables reflect information that applies to components in both units. When the performance history and probabilistic risk analysis ranking of a component group on one unit dictated a more conservative extension, that more conservative extension was applied to both units.
i
l Document Control Desk l If you have any questions or would like additional information on this subject, please feel free to contact me or Jack Rainsberry at (949) 368-7420.
Sincerely, i
l Enclosures cc:
E. W. Merschoff, Regional Administrator, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 & 3 J. W. Clifford, NRC Project Manager, San Onofre Units 2 and 3 l
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