ML20209E485
| ML20209E485 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 04/21/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20209E469 | List: |
| References | |
| NUDOCS 8704300060 | |
| Download: ML20209E485 (3) | |
Text
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UNITED STATES l'
~,f, NUCLEAR REGULATORY COMMISSION WASHING TON. D. C. 20555 1.,*****,o#SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0. 4 TO FACILITY OPERATING LICENSE NO. NPF-47 GULF STATES UTILITIES COMPANY RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458
1.0 INTRODUCTION
By letter dated January 28, 1987, Gulf States Utilities (GSU), the licensee for River Bend Station Unit 1, proposed a Technical Specification (IS) change to Appendix A to Facility Operating License NPF-47. The proposed change involves the deletion of Specification 4.6.2.2.b from the overall Drywell Bypass Leakage Surveillance Requirements as specified in Specifi-cation 4.6.2.2.
Currently the drywell bypass leakage rate tests are required at intervals no greater than 18 months.
This time interval is sufficient to allow testing during the refueling outage of an average fuel cycle.
The present cycle, however, has been extended to August 1987 while
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the drywell test is required to be performed no later than April 25, 1987.
Without a TS change, compliance would require a station outage in April 1987 to perform this test.
Deletion of Specification 4.6.2.2.b will allow an individual extension not to exceed 25% of the surveillance interval but the combined interval for three consecutive intervals should not exceed 3.25 times the surveillance i
interval.
Therefore, approval of the proposed TS change would allow the River Bend Station to continue to operate until August 1987 which is the approximate schedule for the next refueling outage.
2.0 EVALUATION Specification 4.6.2.2 requires that the drywell be leak tested at periodic intervals.
This test is conducted to insure that the bypass flow area between the drywell and the containment airspace is always less than the maximem allowable area the containment can accommodate without exceeding the design pressure in the event of a LOCA.
The acceptance criteria for the allowable tested bypass flow area is given in Specification 3.5.2.2.
This tested value is 1 5 of the maximum allowable area. As discussed in FSAR Section 6.2.1.1.3.4, the design value of A/ K or the allowable bypass area is given as 1.0 square feet.
The intent of the above surveillance requirements, as stated in the SRP Section 6.2.1.1.C Appendix A, is to require a leakage test during each refueling outage. The refueling outage was selected because it repre-sented a time period which occurs at regular time intervals throughout I
8704300060 870421 PDR ADOCK 05000458 P
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the life of the plant and is of sufficient duration to accommodate this ccmplex test without requiring a unique plant shutdown.. For the River Bend Station, this time interval was referred to in the TS as a maximum
/ time interval of 18 months rather than each refueling outage.
r Providing a certain degree of scheduling flexibility by referring to the
-time interval as each refueling outage was deemed appropriate for two reasons. First of all, the major. penetrations, where leakage is most likely to occur, are surveilled and/or leak tested at least every 31 days. Therefore, all significant suppression pool bypass pathways are verified to be in the correct configurations on at least a monthly inter-val.
Secondly, the drywell structure is not expected to significantly i
, change between refueling outages. The philosophy of a flexible testing 1 i schedule is further supported by the results of the drywell leakage tests conducted at River Bend.
The pre-operational test conducted in February y 1985 showed that at the design pressure of 24 psig, the[ measured leakage was about 25% of the allowable limit. The next test occurred in October 1985, where the test results showed a leakage area of about 14% of the allowable limit of 0.1 square feet.
a The proposed deletion of Specification 4.6.2.2.b is consistent with the abovestatedstaffobjectives.
Deletion of this specification would allow Specification 4.0.2 to be applicable for'the determination of the l
drywell leakage test interval.
The provisions of Specification 4.0.2 l
allow the licensee to extend the test interval from the nominal 18 months to as much as 22.5 months as long as the combined interval for three consecutive intervals does not exceed 3.25 times the surveillance interval.
This flexibility has been shown to be needed for continued operatio.n until I
the next scheduled refueling outage. Therefore, the proposed change would reduce the unnecessarily restrictive requirement currently containe,d within the TS.
3.0 ENVIRONMENTAL CONSIDERATION
. This amendment involves a change to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase in the amounts,'and no signifi-cant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this sendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical l
exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
j no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.
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4.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1);there is reasonable assurance that the health and safety of
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the public will not be endangered by operation in the proposed manner, and
'1 (2) such activities will be conducted in compliance with the Commission's A
regulations and the issuance of this amendment will not be inimical to the comon defense and the security nor to the health and safety of the public.
Principal Contributor:
J. Kudrick
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Dated:
April 23, 1987
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