ML17263A376
| ML17263A376 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 08/30/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17263A375 | List: |
| References | |
| TAC-M83570, NUDOCS 9309080109 | |
| Download: ML17263A376 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055~1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
53TO FACILITY OPERATING LICENSE NO.
DPR-18 ROCHESTER GAS AND ELECTRIC CORPORATION R.
E.
GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244
1.0 INTRODUCTION
By letters dated April 23,
- 1992, and August 6, 1993, the Rochester Gas and Electric Corporation (the licensee) submitted a request for changes to the R.
E. Ginna Nuclear Power Plant (GNPP) Technical Specifications (TS).
The requested changes proposed that the snubber visual inspection schedule in the existing TS be removed and replaced with an alternative visual inspection schedule as recommended by the NRC in Generic Letter (GL) 90-09, "Alternative Requirements For Snubber Visual Inspection Intervals and Corrective Actions,"
dated December ll, 1990.
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~Re ister notice.
The snubber visual inspection schedule in the existing TS is based on the permissible number of inoperable snubbers found during the previous visual inspection, irrespective of the total population of snubbers.
A snubber is considered inoperable if it fails the acceptance criteria of the visual inspection as specified in TS.
As a result, licensees with a large snubber population find the schedule excessively restrictive.
The purpose of the alternative visual inspection schedule is to allow the licensee to perform visual inspections and corrective actions during plant outages without reduction of the confidence level provided by the existing visual inspection schedule.
The new visual inspection schedule specifies the permissible number of inoperable snubbers for various snubber populations.
The basic inspection interval is the normal fuel cycle, up to 24 months.
This interval may be extended to as long as twice the fuel cycle or reduced to as small as two-thirds of the fuel cycle depending on the number of unacceptable snubbers found during the previous visual inspection.
- 2. 0 EVALUATION Snubbers are installed to ensure that the structural integrity of the re'ctor coolant system and all other safety-related systems is maintained during and following a seismic event.
Snubbers are used to restrain piping or equipment during seismic events or transient loads, yet allow relatively unrestrained movements of the piping/equipment during normal heatup or cooldown operations.
The purpose of the visual inspection surveillance requirement (TS 4.14) is to
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ensure that no observable deficiencies exist with any snubber installation that would render a snubber inoperable.
Snubber inser vice inspection requirements consist of visual inspection and functional testing.
Visual inspection is intended to identify potential impairment to operability caused by leakage, corrosion or degradation due to environmental exposure.
Functional testing typically involves removing the snubber from the system and performing testing on a specifically-designed test stand to verify its ability to operate within specified performance limits.
In general, functional testing is intended to provide a 95X confidence level that 90 to 100X of the snubbers are operable within acceptable limits.
The performance of the visual inspection is a separate process which is complimentary to the functional testing program and provides additional confidence in snubber operability.
The staff finds the alternative visual inspection schedule provided in the proposed TS changes to be consistent with the schedule recommended in GL 90-09.
To support conformance with the guidance of GL 90-09, the licensee compared data gathered on GNNP's hydraulic and mechanical snubbers to the data reported by Brookhaven National Laboratory (BNL).
The BNL report, "Development of Alternative Snubber Surveillance Requirements:
Recommended Interim Snubber Surveillance Plan," dated June 12,
- 1989, was prepared for the NRC in support of GL 90-09.
The methodology presented in the BNL report is the basis for GL 90-09.
According to the licensee, the results of the data gathered on GNPP compared favorably to the data evaluated by BNL.
The results from both GNPP and BNL data analyses showed that the failure rates found for visually inspected and functionally tested snubbers are low.
In addition, the failure rates for GNPP's visual inspections also compared favorably to those of functionally tested snubbers.
The visual inspections had failure rates of 6.0X and 4.0X for hydraulic and mechanical
- snubbers, respectively.
The corresponding failure rate of snubbers when subjected to an actual test was 2.2X.
These results are documented in Ginna Safety Evaluation Number NSL-OOOO-SE004, which has been internally reviewed and approved by Ginna's Plant Operations Review Committee (PORC).
The staff notes that the above-reported failure rates for GNPP are very compatible with the percentages of unacceptable snubbers indicated in the proposed visual inspection schedule.
The staff also concurs with the licensee that the proposed amendment complies with the snubber reliability criterion that a minimum of 90X of the snubbers (in the group) be operable in the next inspection period.
Based on the above information, the staff finds that the proposed alternative visual inspection schedule is consistent with the guidance contained in GL 90-09 and is acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the New York State official was notified of the proposed issuance of the amendment.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION The 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 NRC 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
- offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a
proposed finding that the amendment involves no significant hazards con-sideration, and there has been no public comment on such finding (57 FR 58250).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
- 5. 0 CONCLUSION Based on the above evaluation, the staff concludes that the licensee's proposed changes to the existing GNPP TS on snubber visual inspection schedule is consistent with the guidance of GL 90-09.
The proposed alternative inspection schedule is considered acceptable.
The Commission has concluded, based on the considerations discussed
- above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
Arnold Lee Date:
August 30, 1993