ML20217J238

Informs That Attached Questions Transmitted by Fax on 991013 to J Rainsberry of Southern California Corp to Prepare for Upcoming Telephone Call

ML20217J238
Person / Time
Site:	San Onofre
Issue date:	10/13/1999
From:	Raghavan L NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-MA4509, TAC-MA4510, NUDOCS 9910250052
Download: ML20217J238 (4)

Text

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, 9 . . . . . ,o October 13,1999

, J MEMORANDUM FOR: Docket File FROM: ] L. Raghavan, Senior Project Manager -

Project Directorate IV, Section 2

-. Division of Licensing Project Management Office of Nuclear Reactor Regulation

SUBJECT:

SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 '

AND 3 - FACSIMILE TRANSMISSION, ISSUES TO BE DISCUSSED IN AN UPCOMING PHONE CONVERSATION ON RISK-INFORMED INSERVICE TESTING PROGRAM (TAC NOS: MA4509 and MA4510)

The attached questions were transmitted by fax today to Mr. Jack Rainsberry of Southem i Califomal Corporation (SCE) to prepare him and others for an upcoming telephone call. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.-

s Docket Numbers 50-361 50-362 Distribution l PUBLIC -

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September 29,1999 COMMENTS ON SAN ONOFRE RESPONSE TO

' NRC REQUEST FOR ADDITIONAL INFORMATION ON RISK-INFORMED IST

1. Section 3.1, " Inservice Testing Program Changes" of the licensee's December 30,1998, Al IST Program Plan describes additional testing for check valves, AOVs, HOVs and pumps. This additional testing should be included in the licensee's Rl-IST Program i Description. For example, the description of check valve testing in the RI IST Program Plan seems fairly consistent with the ASME risk-informed check valve Code Case OMN-

- 4 which would probably be acceptable to the staff (possibly with certain limitations).

2. . Section 3.3, " Performance Monitoring of IST Components," of the licensee December '

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30,1998, RI IST Program Flan describes " additional monitoring for each component group." This monitoring should be included in the licensee's RI-IST Program Description. How often 'will these monitoring activities be conducted?

3. In describing how the test interval will be extended for components categorized LSSC, the licensee deleted the phrase abased on evaluation of design, service condition, and performance history" from Section 4, " Testing Philosophy" of the licensee's June 17, 1999, RI-IST Program Description. This phrase should be included in the RI-IST Program Description consistent with the guidance provided in Section 3.1 of RG 1.175.

. 4. Section 5, " Implementation" of the licensee's June 17,1999, RI IST Program Description describes implementation strategies for components categorized as LSSC.

Are these commitments equally applicable to components categorized as LH? If so, this 4 should be reflected in the licensee's RI-IST Program Description, if not, discuss how I the selected compensatory actions will detect component degradation in a timely manner.

5. Will all SOVs and manual valves be exercised at least once during each operating cycle consistent with the guidance in RG 1.175 (e.g., as a result of normal plant operation during the operating cycle)? If so, this should be reflected in the licensee's RI-IST Program Description.- The licensee's December 30,1998, RI-IST Program Plan I

, Indicates that AOVs and HOVs will be exercised at least once during each operatim cycle. This should be reflected in the RI-IST Program Description consistent with 1,L guidance provided in Section 3.1 of RG 1.175.

6. What criteria will be used by the licensee to determine when the test interval can be  !

extended for components (categorized as LSSC or LH) that have limited or poor  !

performance histories.'

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17. What is the basis for inclubing the "plus a 25% margin" in the proposed extended test 3 intervals? Was the added margin included in the licensee's assessment of the overall )

change in risk? - Was this margin considered by the licensee in assessing whether each i

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kshminaras Righav:n rIl#2fi4.wpd Paga 2l component's test interval is justified based on its performance history? The 25% margin sometimes allowed to complete technical specification surveillance requirements is typically applicable to intervals much shorter than 6 years.

8. Section 2.2.1.1, "The Use of Multiple Risk Metrics to Ensure Defense-in-Depth," of the licensee December 30,1998, RI-IST Program Plan describes the use of LERF as a risk metric. _ in addition, the following considerations were listed; " containment isolation features that may not directly impact the value of LERF", and " interfacing systems LOCA that provides a direct release path to the outside containment". These considerations should be included in the licensee's Ri-IST Program Description. Also,

. the licensee's June 17,1999, RI-IST Program Description states that the exercise test I for certain (presumably LSSC) check valves will be assigned consistent with Appendix J,

- Option B criteria. What is the technical basis for extending the test intervals for these

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- valves (please identify the specific valves)? Explain how redundancy and diversity of the containment isolation function will be maintained.

9.- Section 1 of the RI-IST Program Description describes the PRA scope and quality

- (review process) that was used in the original categorization. Consistent with the other sections of the Program Description (e.g., Section 4 - Testing Philosophy), Section 1 should be re-worded to state that a similar scope and review process will continue to apply for future uses of the PRA for RI IST categorization and for determinatior, of change in risk from the change in test interval.

.10. ' In Section 2 of the Program Description, the first sentence under the "

Methodology / Decision Criteria for PRA" proposes a methodology which "may" be used when the program is reassessed. If this methodology is not used, the Program Description should state what the alternatives are.

11.- 'In Section 2 of the Program Description under "PRA Limitations", sensitivity analysis to component failure probabilities is not included (although this sensitivity analysis was performed .in the original categorization process).~ . Please explain why this sensitivity was omitted. <

12. Section 3 of the Program Description describes the integrated decisionmaking process.

' However, the requirements for the use of the Expert Panel is not included in this section.

Key aspects of Section 2.4 of the licensee December 30,1998, RI-IST Program Plan (or the appropriate sections ~of AS.ME Code Case OMN-3) should be included in the Program Description.

13. Under " Categorization Guidelines"in Section 3 of the Program Description, the

_ quantification of risk change should be included. The methodology for the modeling of the cause-effect of relaxing test intervals (i.e., modeling of the impact of the change on SSC availabilityheliability, on initiating event frequency, and on CCF probabilities) should be included as part of this description. The key aspects of Section 2.3.3 of the licensee December 30,1998, RI-IST Progrcm Plan should be included in the Program Description.

14. ' The licensee should clarify its resolution of the condition on the use of ASME Code

hLakshminar".s Raghav

n _- rii#2fi4.wp# Paga 3l L Case OMN-1 with respect to consideration of risk insights if extending exercise frequencies for MOVs with high risk significance beyond the quarterly frequency specified in the ASME Code. This consideration should include assurance that the increases in core damage frequency and/or risk associated with the increased exercise interval for high-risk MOVs are small and consistent with the intent of the Commission's {

Safety Goal Policy Statement. l

' 15. The licensee should clarify that its commitment to OMN-1 includes exercising of each ,

MOV in its risk-informed IST program at least every year or refueling cycle (whichever is I

, longer).

, _16. The licensee should clarify that it is evaluating test data for degradation and is establishing plans to test grouped MOVs on a staggered basis in support of its initial test intervals that exceed the guidance of two refueling cycles or 3 years (whichever is longer)in Paragraph 3.3.1 of OMN-1.

17. 'The licensee should clarify that its grouping of MOVs will include such aspects as system conditions and valve internal materials.

18. The licensee'should clarify its basis for the extension of MOV seat leakage testing intervals and the relationship of those intervals to Appendix J of 10 CFR Part 50.

19. The licensee should clarify the status of its development of procedures to implement OMN-1, 1

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