ML20072E991
| ML20072E991 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/17/1994 |
| From: | Rosenblum R SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20072E994 | List: |
| References | |
| NUDOCS 9408230162 | |
| Download: ML20072E991 (6) | |
Text
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August 17, 1994
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,...o U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket Nos. 50-361 and 50-362 One-time Exemption from 10CFR50, Appendix J Amendment Application Nos. 143 and 127 Change to Technical Specification 3/4.6.1.2,
" Containment Leakage" San Onofre Nuclear Generating Station Units 2 and 3
Reference:
1)
December 30, 1993, letter from R. M. Rosenblum (Edison) to Document Control Desk (NRC),
Subject:
Proposed Change Number 299, Technical Specification Improvement Project, San Onofre Nuclear Generating Station, Units 2 and 3."
Provided as Enclosure 1 is a request for a one-time exemption from 10CFR50, Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors,"Section III.D.1.(a).
This one-time exemption will allow a schedule for Type A Integrated Leak Rate Tests such that the three tests performed during the current 10-year service period will not be performed at approximately equal intervals. provides Amendment Application Nos. 143 and 127 to Facility Operating Licenses NPF-10 and NPF-15, respectively, for the San Onofre Nuclear Generating Station, Units 2 and 3.
These Amendment Applications consist of Proposed Change Number (PCN) 438.
PCN 438 is a request to revise Technical Specification (TS) 3/4.6.1.2, " Containment Leakage" to extend the interval between ILRTs to 60 i 10 months on a one-time basis to reflect the one-time exemption described in Enclosure 1.
This exemption would save approximately 110 critical path hours per unit during the Cycle 8 refueling outages. At an estimated power replacement cost of approximately $16,000 per hour (according to the Units 2 and 3 Cycle 7 optimization estimatas) this results in approximate savings of $1,760,000 per unit.
In addition, a savicqs of approximately 2800 hours0.0324 days <br />0.778 hours <br />0.00463 weeks <br />0.00107 months <br /> of labor and 2000 mrem exposure per unit will clso be realized.
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Document Control Desk Southern California' Edison (Edison) is following the NRC efforts to revise 10CFR50 Appendix J.
It is our understanding that the proposed changes being i
considered by the NRC will require only one ILRT to be performed every 10 years.
If the rule is revised prior to the Units 2 and 3 Cycle 9 refueling outages these ILRTs will not be required at all and the savings outlined above will be real savings, as opposed to deferred costs.
Therefore, this amendment request is a Cost Beneficial Licensing Action.
As noted in Enclosure 1, Edison is currently performing a level 3 PRA to support this exemption request and proposed TS change and will provide the results of this PRA by October 1, 1994.
Edison requests NRC approval of these exemption and amendment requests for use during the-Units 2 and 3 Cycle 8 refueling outages.
The Unit 2 outage is currently scheduled to begin in February 1995.
If you would like additional information regarding these exemption and Technical Specification change requests, please let me know.
Sincerely,
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L. J. Callan, Regional Administrator, NRC Region IV K. E. Perkins, Jr., Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 1, 2, and 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 H. Kocol, California Department of Health Services 1
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ENCLOSURE 1 ONE TIME EXEMPTION REQUEST FROM 10CFR50 APPENDIX J REQUIREMENTS SAN ON0FRE UNITS 2 AND 3 1
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REQUEST FOR EXEMPTION FROM 10CFR50 APPENDIX J, SECTION III.D.1.(a)
SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 Southern California Edison (Edison) hereby requests a one-time exemption from the requirement of 10CFR50, Appendix J, Section III.D.l.(a) for San Onofre Units 2 and 3 to perform the three Type A Primary Reactor Containment Integrated Leak Rate Tests (ILRTs) to be performed during the current 10-year service period at approximately equal intervals.
This exemption will allow a one-time test interval of 60 10 months such that the ILRTs that are currently scheduled for the Units 2 and 3 Cycle 8 refueling outages may be delayed until the respective Cycle 9 outages.
According to 10CFR50.12.a.2, the NRC will grant an exemption to a requirement if special circumstances are present. According to 10CFR50.12.a.2.ii, special circumstances are present when " Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule;"
The purpose of Appendix J leak test requirements, as stated in the Introduction to 10CFR50 Appendix J, is to " assure that (a) leakage through the primary reactor containment and systems and components penetrating primary containment shall not exceed allowable leakage rate values as specified in the technical specifications or associated bases and (b) periodic surveillance of reactor containment penetrations and isolation valves is performed so that proper maintenance and repairs are made during the service life of the containment, and systems and components penetrating primary containment."
This exemption request concerns part (a) of the stated purpose of Appendix J.
Part (b) of the stated purpose of Appendix J applies to penetrations and isolation valves, which are tested by Type B and C Local Leak Rate Tests (LLRTs).
10CFR50 Appendix J, Section III.D.1(a) requires three Type A tests at approximately equal intervals during each 10-year service period.
Technical Specification 4.6.1.2 requires three ILRTs to be performed at 40 i 10 month intervals during each 10-year service period. According to this schedule, an ILRT will need to be performed during the Units 2 and 3 Cycle 8 refueling outages.
The proposed one-time exemption would allow these ILRTs to be delayed until the Cycle 9 refueling outages.
The most recent ILRTs for Units 2 and 3 were performed in October 1991 and March 1992, respectively.
The proposed exemption would result in a one-time ILRT test interval of 60 t 10 months. As required by Appendix J, three ILRTs will still be performed during the current 10-year service period.
(In the event Appendix J is revised to revise this requirement, the San Onofre schedules would also be revised.)
For Unit 2 the current 10-year service period is from February 16, 1992 to February 16, 2002.
For Unit 3 the current 10-year service period is from November 15, 1992 to November 15, 2002.
Data available for San Onofre Units 2 and 3 show that since 1988 there have been only 2 local leakage rate tests detecting leakage rates greater than 0.6 L, for Type B and C penetrations out of approximately 830 total penetrations l
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Data previousEt'o 1988 involves startup issues and is not representative of the current performance basis.
Both of the leakage rate failures were actually detected by LLRTs.
No excessive local leaks have been detected by Type A testing at San Onofre Units 2 and 3 during this period.
This leakage rate test history demonstrates that the leaktightness of.the 4
containment penetrations at San Onofre Units 2 and 3 has been consistently.
within acceptable levels. Also, for the two cases when there have been excessive local leakage rates, a Type A ILRT was not necessary to detect the leakage.
Type A testing is also used to detect the leaktightness of the containment at elevated pressures, or the potential for gross containment failure mechanisms.
s Gross containment failure is considered to be a very unlikely event, and in-4.
fact, since Units 2 and 3 have been in' operation, neither Unit has ever failed a Type A ILRT.
Therefore, an exemption from the schedule requirements for performing an ILRT should not result in a significant decrease in the i
confidence in the leaktightness of the containment structure and the underlying purpose of the rule would be met.
Therefore, pursuant to 10CFR50.12.a.2, Edison requests an exemption from the schedule requirements of 10CFR50, Appendix J, Section III.D.l.(a).
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ENCLOSURE 2 PROPOSED CHANGE NUMBER 438 CONTAINMENT LEAK RATE TESTING SAN ONOFRE UNITS 2 AND 3