ML20083D057
| ML20083D057 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 05/16/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20083D056 | List: |
| References | |
| NUDOCS 9505240140 | |
| Download: ML20083D057 (3) | |
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UNITED STATES 3
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2006N1001 49.....,o l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMEN 0 MENT NOS. 201 AND 204 TO FACILITY OPERATING LICENSE NOS. DPR-44 and DPR-56 PECO ENERGY COMPANY PUBLIC SERVICE ELECTRIC AND GAS COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY PEACH BOTTOM ATOMIC POWER STATION. UNIT NOS. 2 AND 3 DOCKET NOS. 50-277 AND 50-278
1.0 INTRODUCTION
By letter dated August 3, 1994, the PECO Energy Company (the licensee) subeltted a request for changes to the Peach Bottom Atomic Power Station, Unit Nos. 2 and 3, Technical Specifications (TS). The requested changes would implement a snubber functional test surveillance interval of 24 months. The amendments change the current one-time snubber functional test interval to a permanent interval of 24 months.
2.0 BACKGR00ND Surveillance Requirement 4.ll.D.4 in the existing Peach Bottom TS addresses functional test requirements for mechanical and hydraulic snubbers. As a part of PECO's change to a 24-month fuel cycle, a TS change request to extend the testing period of snubbers from 18 months to 24 months was submitted to the NRC in a letter dated September 28, 1992. Additional information regarding the snubber surveillance period was provided by PECO in a letter dated July 7, 1993. The NRC safety evaluation (SE) dated August 2, 1993, approved a one-time change to the snubber functional testing period to 24 months, as indicated by a footnote to page 234b of the TS.
The current TS change request concerns the elimination of the above conditional approval and the footnote on page 234b of the TS for both Units 2 and 3 and implementation of a permanent 24-month snubber functional test surveillance interval.
3.0 EVALUATION In its August 3, 1994 letter, the licensee stated that changing the inspection interval to 24 months will not significantly impact the functional testing program to confirm the operability of the snubber population. The original interval of 18 months was selected to accommodate the need to test snubbers 1
9505240140 950516 PDR ADOCK 05000277 P
that were inaccessible during operation.
Past functional test results have not identified any failure mechanisms that would have been more severe had there been an extension of service interval between functional tests.
A historical search of the snubber functional test records at Peach Bottom was also conducted by the licensee in 1992, in accordance with the requirements of Generic Letter 91-04, " Changes in Technical Specification Surveillance Intervals to Accommodate a 24 Month Fuel Cycle."
This search identified some engineering analy: sis was performed for these snubbers and the resultssnubbers indicated that the associated piping system remained operable.
In addition, the licensee stated that each of the snubbers that did not meet the screening criteria was either reconditioned or replaced.
The Peach Botton TS requires a service life monitoring program for snubbers to ensure that they will not remain in service past their recommended service life. The TS also requires that if a snubber's service life is projected to expire prior to the next scheduled review (i.e., refueling outage), then the snubber must be reconditioned, replaced or reevaluated to extend its service life.
Snubbers do not require preventative maintenance, except for seals on.
hydraulic snubbers which are replaced as part of the service life monitoring program. The seals of all hydraulic snubbers that are projected to exceed their recommended service life during the next cycle are either replaced or reconditioned.
According to the ASME OM Code, 1990 Edition, and ASME Code Section XI, for plants with an 18-month test interval, there is the possibility that all snubbers are not functionally tested every 15 years (i.e.,10 percent of snubbers every 18 months, yielding 100 percent test every 15 years). This is because of the Code provision that requires the consideration of
" representative sample" where certain snubbers are tested on a more frequent basis than the others, due to design, location and size.
In addition, several facilities have well in excess of 370 snubbers and, in accordance with the "37-Plan" sampling provision of the OM Code, these plants would require more than 15 years to test 100 percent of the snubbers, assuming that no failures would result from the test. Therefore, the 18-month interval should not be considered as a prerequisite for an acceptable sampling plan for snubber functional testing.
Based on the above, the staff concurs with the licensee's argument that the original interval of 18 months was selected mainly to accommodate the need to test snubbers that were inaccessible during operation. The sample size of 10 pucent appears to have been arbitrarily selected which, when applied with the 18-month interval, would lead to a test period of 15 years, perceived to be a conservative test period for snubbers.
The staff determined that (1) changing the inspection cycle to 24 months will not significantly impact the functional testing program to confirm the operability of the snubber population, (2) snubber functional testing has shown no failure mer.hanism which would be aggravated by an extension of the test interval to 24 months, and (3) the snubber service life monitoring l
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- program remains to be part of the TS and will continue to be effective in identifying snubbers which need to be reconditioned or replaced when their recommended service lives are projected to expire prior to the next refueling outage.
Based on the above information, the staff concluded that the proposed TS changes to extend the functional test interval to 24 months on a permanent i
basis are compatible with the guidance of Generic Letter 91-04, for a 24-month fuel cycle. Furthermore, for the reasons discussed above, the snubber functional t1st TS requirements will continue to provide assurance of snubber operability and are, therefore, acceptable.
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4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change the surveillance requirements. The NRC staff has determined that the amendments involve 'no significant increase in the amounts, and no significant change in the types, of any effluents that may be released 4
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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (60 FR 3676). Accordingly, the amendments meet 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 amendments.
6.0 CONCLUSION
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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
A. Lee Date: May 16, 1995
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