ML20112B992
| ML20112B992 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/06/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20112B987 | List: |
| References | |
| NUDOCS 8501100741 | |
| Download: ML20112B992 (4) | |
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4 UNITED STATES
[ QQ NUCLEAR REGULATORY COMMISSION Gg
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SAFETY' EVALUATION BY THE OFFICE OF NU". LEAR REACTOR REGULATI0f.
RELATED TO THE ONE-TIME EXTENSION OF CERTAIN VALVES FROM THE REQUIREMENTS OF APPENDIX J CAROLINA POWER & LIGHT COMPANY BRUNSUICK ST.EAM ELECTRIC PLANT, UNIT 1 DOCKET NO. 50-325 1.0 Introduction By letter dated September 4,1984, as supplemented October 22, 1984 the Carolina Power & Light Company (CP&L, the licensee) requested an amendment to Facility) Operating License No. DPR-71 for the Brunswick Steam Electric Plant (BSEP, Unit 1.
The amendment would permit a one-time extension of the test period for Type B and C local leak rate tests for certain valves from December 12, 1984, or later, until the next refueling outage, which is currently scheduled to begin on or before March 31, 1985.
In addition, the test period for the main steam isolation valves (MSIV) is extended twelve days.
_ _ _ 2.0 Background Brunswick ' Unit I was shut down for a refueling outage beginning in late 1983. The Type B and C local leak rate tests and MSIV tests were done over a period of the first three or four months beginning in December. -This outage lasted longer than expected due to unforeseen events.
In addition, the next operating cycle was extended from 12 months to 18 months. The con'bination of the extended outage and the extended cycle caused the two-year inspection. interval to end before the current operating cycle.
Since the winter electrical load peak period of the CP&L system occurs at the sane time as the inspection period, it is desirable to postpone the inspections until the next refueling outage which. is scheduled to begin on or before March 31, 1985. The longest extension would be for the valves tested December 12, 1982, a total of about 31 months. The inspection period for the main stcan isolation valves ends March 18, 1985 so the '
extension for those valves would be a matter of 12 days.
We have reviewed the licensee request and find that approximately one-half of the tests may be delayed until tne refueling outaoe which begins on or before March 31, 1985.
The basis of our conclusion is given in the following evaluation.
3.0 Evaluation By letter dated September 4, 1984, from A. Cutter, CP&L, to D. Vassallo, NRC,.tte licensee requested an cxemption from the reonirements of 10 CFR R $ ( og Q B
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_2-50, Appendix J, so as to extend the two year testing interval for most of the Brunswick Unit 1 primary containment penetrations. This request for exemption, if granted, would allow the licensee to perform the required Type B and C leak tests on containment penetrations during the next scheduled refueling outage, which the licensee has committed to begin no later than March 31, 1985.
In a follow-up letter, dated October 12, 1984, the licensee provided, for each primary containment penetration, information on the test results from previous local leak rate tests (LLRTs), whether the penetration could be tested during normal power operations, and the estimated dose to plant personnel while performing the leak tests if the tests were performed during the power run.
The staff has reviewed the information contained in the above referenced letters and has concluded that it would be acceptable to postpone, until the March 31, 1985 scheduled refueling outage, the required LLRTs for
,approximately one-half of the Brunswick Unit 1 primary containment penetrations. These penetrations are identified in Table 1.
Accordingly, an exemption from the requirements of Appendix J,10 CFR 50 should be granted for the valves identified in Table 1, until March 31, 1985.
L The staff has concluded that the requested exemption should not be granted for the remaining containment penetrations.
Our bases for this finding are the. poor LLRT histories and/or the fact that the penetrations can be readily tested during normal plant operations. The previous LLRTs for a portion of these penetrations show a history of poor leak tightness.
For
.many of these penetrations, the test pressure could not he maintained. The balance of these penetrations can be readily tested during normal plant operations, without affecting the safety of the plant or resulting in significant radiation exposure to the plant personnel performing the leak tests. Accordingly, the remaining containment penetrations whose LLRT requirements are also governed by 10 CFR 50, Appendix J, shall be tested in accordance with the time interval specified in Appendix J.
The staff's conclusion that some of the containment penetration LLRTs for Brunswick Unit 1 can be postponed until the Parch 31, 1985 refueling outage without presenting a significant safety concern is based on the following considerations:
1.
During the past two year operating cycle, there was an extended naintenance outage of approximately eight months during which the plant components were not exposed to the normal operating tenperature, pressure, and radiation conditions. The time interval of 24 months specified in Appendix J for Type B and C tests was based, in part, on the expected degradation of components exposed to the environment resulting fron a full 24 months of normal plant operations. The total exposure time for the containment penetrations to the normal plant operating environnent at Brunswick Unit I will be substantially less
.. than 24 months, including the time period involved in the extension to March 31, 1985.
2.
The favorable results of previous LLRTs performed during past outages was a major factor in the staff's decision.
Each penetration listed in Table 1 has a very good history of substantially lower than normal leak rates based on the previous LLRTs. These previous test results provide a high degree of assurance that an extension in the 24 month test interval requirement will not result in a significant decrease in the integrity of these penetrations.
3.
The 24 month interval requirement for Type B and C penetrations is intended to be often enough to prevent significant deterioration from occurring and long enough to permit the LLRTs to be performed during plant outages.
Leak testing of the penetrations during plant shutdown is preferable because of the lower radiation exposures to plant personnel. Moreover, some penetrations, because of their intended functions, cannot be tested at power operation.
For penetrations that cannot be tested during power operation or those that, if tested during plant operation would cause a degradation in the plant's overall safety (e.g., the closing of a redundant line in a safety system), the increase in confidence of containment intr rity following a
a ' successful test is not significant enough to justify a plant i
shutdown specifically to perform the LLRTs within the 24 month time period, as long as the penetrations are in compliance with Itens 1 and 2 above.
4.0 Conclusion Based on the above review, the staff concludes that extending the surveillance interval as described is acceptable for approximately one-half of the valves. The valves for which the surveillance interval may be extended to March 31, 1985 are identified in Table 1.
Enclosure:
Table 1 Principal Contributor:
M. Fields Dated:
December 6,1984
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TABLE 1 LIST OF BRUNSWICK 1 CONTAINMENT PENETRATIONS WHOSE LLRTs CAN BE DELAYED UNTIL MARCH 31, 1985, REFUELING OUTAGE Penetrations are identified by their Test No. (from October 22, 1984, licensee letter),
Test No.
TestNo.(cont'd)
CAC-1 E11-26 thru E11-32 CAC-2 E21-1 thru E21-5 CAC-9 thru CAC-12 E21-7 CAC-Ik thru C,AC-26 E21-8
. CAC-29.thru CAC-42 E41-2 CAC-45 E41-4 E11-1 E41-6
'E11-2 E41-8 E11-4 '
E51-2 thru E51-4 E11-6 G31-2 E11-11 SA-1 E11-12 TIP-1 thru TIP-5
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E11-15 thru E11-17 Also, the Main Steam Isolation Valves E11-19 B21-F022A, F028A E11-20 B21-F022B, F02SB E11 B21-F022C, F028C E11-24 B21-F0220, F028D 5
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