ML20236A680
| ML20236A680 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 10/19/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236A678 | List: |
| References | |
| NUDOCS 8710230026 | |
| Download: ML20236A680 (2) | |
Text
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NUCLEAR REGULATORY COMMISSION l
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r2 WASHINGTON, D. C. 20555 i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING' AMENDMENT NO. 51 TO FACI,LITY OPERATING LICENSE N0. NPF-11 1
COMMONWEALTH EDISON COMPANY i
LASALLE COUNTY STATION, UNIT 1 l
DOCKET N0. 50-373
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1.0 INTRODUCTION
By. letter dated June 16, 1987, the Commonwealth Edison Company. requested to amend Facility Operating License NPF-11..The proposed revision will permit the LaSalle County Station Unit 1 to perform the required snubber 1
functional tests in approximately 22 months + 25% instead of 18 months
._ 25% on a:one time basis.
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9 2.0 DISCUSSION To verify the operability.of safety related-snubbers, Technical Specifications
.(T.S.) of.LaSalle 1 require the plant to perform functional testing on safety-related snubbers every 18 + 25% months according to any one of the acceptable sampling plans lis'ted. However, due to the extended period of outage after Cycle 1, the next outage will occur well beyond the 18 month interval required for the functional tests. The original 18-month period requirement was arbitrarily determined to accommodate the most common fueling outage.
All safety related snubbers were tested during the surveillance performed at l
the LSCS-1 first refueling outage, with 104 snubbers failing to meet acceptance limits. Completion of the surveillance, along with the associated corrective. actions for the test failures, returned the unit's snubber population to a baseline one hundred percent operable condition, j
Certain factors which contributed to the LSCS-1 mechanical snubber failures discovered at the outage were absent, or greatly reduced while the unit was in cold shutdown. The prevailing causes of snubber failures were:
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-low frequency steady state vibration of system piping,
-transient forces due to system startup/ shutdown,
-overheating of snubber which causes lubricant breakdown, and
-corrosion of snubber internals.
Since a significant portion of the snubber surveillance interval (between the first and second surveillance) was spent with the unit in cold shutdown, which is a period of reduced failure potential for the snubber population, the proposed amendment to extend the surveillance interval should not have a significant impact on snubber operability or their ability to maintain the structural integrity of critical piping systems.
7 8710230026 871019 PDR ADOCK 05000373 j
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., All safety-relatsd mechanical snubbers in LSCS-1 will_ be visually inspected per surveillance requirement 4.7.9 b during the current second fuel cycle.. The snubbers in the primary containment, which are nornelly iheccessible during
- reactor power operation. were inspected during-a shortunit outage in June.1987.
The remaining ' snubbers are scheduled.to be inspected in the fall of 1987.
1 Visual inspection of the snubber population provides additional assurance j
that the snubbers are in' good.overall' condition and operable.
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J, The staff.has concluded that' the _ requested Technical Specifications revision of extending the time period between functional tests is acceptable on a-one-time basis as requested.
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3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a, change'in the installation'and use of a facility component. located within.the restricted area as defined in 10 CFR Part 20 and changes in, surveillance requirements. The staff has determined that'
~ i' this amendment involves no significant increase.in the amounts, an6 no significant change in the types, of any. effluents that may be released offsite, and that there is no significant increase in individual or cumula-
- tive occupational radiation exposure. The Commission has,previously issued 1
a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accord-ingly,Lthis' amendment meets the eligibility criteria forbtegorical exclusionsetforthin10CFR51.22(c)(9). Pursuantto10CFR51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuar.ce of this amendment.
4.0- CONCLUSION.
The~ Commission made a proposed determination that the a endment involves no significant hazards consideration which was published in the Federal Register (52 FR 34001) on September 9,1987, and consialted with the -
state of Illinois. No public comments were received, and the state of Illinois"did not have any comments.
The staff has concluded, based on the considerations discussed above, that:
will not be endangered by operation in the proposed manner, and (2) public (1) there is reasonable assurance that the health and safety of the such activities will be conducted in compliance with the Commission's regula-tions and the issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public.
I 5.0 REFERENCE Letter from Commonwealth Edison to NRC, "LaSalle County Station, Unit 1 Proposed Amendment to Technical Specification for Facility Operating License NPF-11", June 16, 1987.
Principal Contributor: Horace Shaw, NRR L
Dated: October 19, 1987 l
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