ML20044B019
| ML20044B019 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 07/11/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20044B017 | List: |
| References | |
| NUDOCS 9007170210 | |
| Download: ML20044B019 (4) | |
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UNITED STATES 6
' 't NUCLE AR REGULA*.*ORY COMMISSION waswiwovoN. o. c. rosss SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
SUPPORTING AMENDMENT NO.75 TO FACILITY OPERATING LICENSE NO. NPF-8 ALABAMA POWER COMPANY JOSEPH M. FARLEY NUCLEAR PLANT, UNIT 2 i
DOCKET NO. 50-364 1.0 I_NTRODUCTION By letter dated February 8, 1990, Alabama Power Company (the licensee) requested changes in the Technical Specification (TS) 4.7.9 relating to snubber visual inspection frequency requirements for Joseph M. Farley Nuclear Plant (Farley), Unit 2.
This amendment modifies the existing snubber visual inspection frequency schedule from one that is independent of the snubber population size to one that is dependent on a snubber population of 200.
The proposal is similar to a TS change submitted by the licensee in Amendment No. 69 to Facility Operating License No. NPF-2 and Amendment No. 61 tn NPF-8, for Farley, Units 1 and 2, and approved by the NRC staff in a letter dated March 30, 1987.
Approval of these amend-ments was granted by the NRC on a one-time only basis due to ongoing generic NRC efforts in this area.
These generic efforts which are now approaching completion are anticipated to result in relief from the current requirements for visual inspection; however, it is not certain that this generic relief will be provided in sufficient time to preclude an aiditional inspection by Alabama Power Company just prior to its next (seventh) Unit 2 refueling outage.
A one-time only TS change is,
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therefore, proposed.
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The next refueling outage for Farley, Unit 2, is currently scheduled for October 1990.
If the proposed amendment is not approved, the licensee would be required to shut down the plant in early August 1990 to satisfy the TS requirements.
2.0 EVALUATION Snubber Visual Inspection Schedule L
The basis for the proposed snubber visual inspection schedule was originally submitted by the licensee on September 2, 1986.
A statistical methodology was used in deriving the proposed snubber visual inspection schedule.
Based on the assumed. statistical model, the proposed visual inspection schedule will provide a 95% confidence level that at least 90%
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of the snubbers in the plant are operable as determined by visual examina-i tions.
It is noted that the existing Technical Specifications require L
both visual and functional tests of snubbers.
The licensee proposed changes in the snubber visual inspection schedule only.
The existing snubber visual inspection schedulc is independent of the snubber population size.
However, the methodology used for the proposed snubber visual inspection schedule depends on the snubber population size.
The licensee used a snubber population size of 200 in deriving the snubber visual inspection schedule in their 1987 submittals.
The current change I
request would, effectively, be applicable only to the Unit 2 inaccessible i
snubber population which exceeds 400 snubbers.
Thus, actual snubber reliability would exceed that utilized by the NRC in their March 30, 1987 approval.
A comparison of the results of the proposed visual inspection j
schedule with the inspection schedule in the generic letter under prepara-
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tion by the staff, indicates that the licensee's approach yields more conservative results. Thus, fewer inoperable snubbers would be permitted l
by the licenst.e's proposed methodology in comparison with the number anticipated to be allowed by the staff's approach in the generic letter 1
under preparation, assuming other parameters such at snubber population and inspection interval are the same.
The licensee indicated in a i
telephone conversation on June 15, 1990, that the actual results of the statistical analysis were less restrictive, but that the proposed numbers for inoperable snubbers were conservatively reduced to the extent necessary to satisfy the relief request requirements of the 1987 submittal j
and, also, to provide an additional margin of safety.
On this basis, the staff finds the licensee's proposed inspection schedule acceptable.
Inoperable Snubber In Visual Examination of Unit 2 An inaccessible hydraulic snubber, 2MS-R88 in the main steam piping system was found unsatisfactory during the last visual inspection because the pivot pin was not engaged in the top ear of the clevis at the pipe side of the snubber.
The snubber was functionally tested with both ends pinned, and found to be acceptable.
It was not tested in the as-found condition because of safety considerations.
An evaluation of the as-found condition indicated that in the case of a dynamic event the snubber would have remained marginally functional but would not have been capable of carrying its designed load.
The evaluation for short-term operability was based on an assumption that the snubber was unpinned because of the uncertainty of whether the vertically oriented pin with the top retaining o
ring missing would have remained partially engaged had a seismic event occurred.
The evaluation concluded that the snubber failure did not adversely affect the short-term operability of the related portions of piping and pipe supports.
i Based on a review of the circumstances and the nature of the snubber failure, the staff finds that inoperable snubber 2MS-R88, was an isolated l
case.
Therefore, the statistical analysis on which the staff's J
acceptance of the proposed methodology for snubber visual inspection
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was based remain valid.
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hi 3.0
SUMMARY
The staff has reviewed and evaluated the licensee's requests.
We have concluded that the proposed snubber visual inspection schedule submitted in the letter dated February 8,1990, provides a level of snubber reliability similar to that of the existing inspection schedule when compared on a consistent statistical basis using the proposed statistical model and snubber population size.
Thus, the proposed one-time TS change that will be 1.1 offect until the startup from the seventh refueling outage at Farley, Unit 2, is acceptable.
Furthermore, we have concluded that the inoperable snubber (i.e., 2MS-R88) found during the last visual inspection at Farley, Unit 2 was an isolated case and the statistical analysis on which the proposed methodology for visual inspection was based is still valid.
- 4. 0 ENVIRONMENTALCONSIDERATJON This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes the surveillance requirements. The staff has determined that the amendment involves no significant increase in-the amounts, and no significant change in the types, of any effluents that may be released off site, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
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Pursuant to 10 CFR 51.22(b), no environmental impact statement or environ-mental assessment need be prepared in connection with the issuance of this amendment.
- 5. 0 CONCLUSION The, Commission made a proposed determination that this amendment involves no significant hazards consideration which was published in the Federal R_egister (55 FR 12588) on April 4, 1990, and consulted with the State of Alabama.
No public comments or requests for hearing were received, i
and the State of Alabama did not have any comments, s
The staff has concluded, based on the considerations discussed above that:
p (1) there is reasonable assurance that the health and safety of the 1
public will not be endangered by operation in the proposed manner, j
(2) such activition will be conducted in compliance with the l,
Commission's regulations, and (3) the issuance of this amendment will not L
be inimical to the commen defense and security or to the health and safety of the public.
Dated:
July 11, 1990 Principal Contributor:
J. Rajan
1 AMENDMENT NO. 75 TO FACILITY OPERATING LICENSE NO. NPF FARLEY, UNIT 2 Beste&4He NRC PDR Local PDR j
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