ML20086C275
| ML20086C275 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 11/08/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20086C267 | List: |
| References | |
| NUDOCS 8311230046 | |
| Download: ML20086C275 (4) | |
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UNITED STATES e
r' NUCLEAR REGULATORY COMM15SiON k.
WASHINGTON, D. C. 20555 s,,,.
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 49 TO FACILITY LICENSE NO. DPR-71 AND AMENDMENT NO. 82 TO FACILITY LICENSE N0. DPR-62 CAROLINA POWER & LIGHT COMDANY BR'JNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 1.0 htroduction By letter dated May 21, 1981, as supplemented October 21, 1982, the C3rolina Power a Light Company (the licensee) submitted proposed changes to the Technical Specifications appended to Facility Operating License Nos. DPR-71 and DPR-62 for the Brunswick Steam Electric Plant (BSEP), Units 1 and 2. The proposed changes would modify the technical specifications to revise the surveillance requirements for hydraulic snubbers as requested by the NRC letter of November 20, 1980. The proposed specifications reflect the specific characteristics of the Brunswick plcnt, suggest editorial changes and provide additional surveillance requirements for hydraulic snubbers. The proposed changes represent improved surveillarice requirements to assure the operability of hydraulic snubbers and the safety related systems that are stabilized by these snubbers.
To reflect accumulated experience obtaine.d from operating plants in the past several years, NRC issued Revision 1 of the Standard Technical Specifications on the surveillance requirements for safety-related snubbers. On November 20, t
U80, this document was transmitted to operating phnts excluding tho3 under Systematic Evaluation Program (SEP) along with a request for submittal of appropriate license amendments to incorporate the requirements of this revision within 120 drys. The same request was extended to SFP ;,lants on March 23, 1981.
2,0 Discussion and Evaluation Numerous discoveries of inoperative snubbers in the period of 1973 to 1975 resulted in incorporating their surveillance requirements in the Technical Specifications for operating reactor plants.
However, several deficiencies were identified after the original requirements were in force for several years. These deficiencies are:
1.
Mechanical snubbers were not included in these requirements.
2.
The rated capacity of snubbers was used as a limit to the inservice test requirement.
8311230046 831108 PDR ADOCK 05000327 P
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NRC approval was necessary for the acceptance of seal materials.
4 Inservice test requirements were not clearly defined.
5.
In-place inservice testing was not permitted.
Since the mechanical snubbers were not subject-to any surveillance requirements, some licensees and permit holders believed..that mechanical snubbers were preferred by NRC. Many plants used mechanical snubbers as original equipment and many others requested to replace their hydraulic snubbers with mechanical ones to simplify or avoid an inservice surveillance program. This is directly contradictory to NRC's intention, where for an unsurveyed mechanical snubber, the mest likely failure is permanent lock-up.
This failure mode can be harmful to the system during normal plant operations.
The licensee does not use mechanical snubbers in the Brunswick plant.
However, if mechanical snubbers are to be installed, in safety-related systems at the Brunswick plant, appropriate Technical Specifications will be proposed by the licensee.
During the period of 1973-1975, when the first hydraulic snubbr. surveillance requirements in the Technical Specificatiens were drafted, a compromise was made to limit the testing of snubber to those with rated capacity of the test equipment and the esquirement to test sone parameters at the snubber
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rated load.
Since then, greater equipment capacity and better understanding of parametric correlation both developed.
To maintain this arbitrary 50,000 lb. limit could mean an unnecessry compromise on plant safety.
The original hydraulic snubber problen started from leakina seals. Most seal materials of the 1973 vintage could not withstand the temperature and irradiation environments. Ethylene propylene was the first material that could offer a reasonable service life for those seals.
In orde~r to discourage the use of unproven material for those seals, the words "NRC approved material" were used in the Technical Specifications.
Staff members i
were asked to approve different seal materials or, many occasions.
Consequently, since the basis for the approval was not defined, the
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development of better seal materials by the industry was actually discouraged.
The not-well-defined acceptance criteria in the earlier version of the testing requirements resulted in non-uniform interpretations and implementation. Acceptance Criteria were set individually at widely different ranges.
Since the rationale of adopting a specific acceptance l
criteria was not clear, NRC inspectors found it impossible to make any necessary corrections.
In some cases, snubbers were tested without preference to acceptance criteria.
l Testing of snubbers was usually accomplished by removing snubbers from their j
installed positions, mounting them on a testing rig, conducting the test, l
- removing them from rig, and reinstalling them to the working position. Many snubbers were damaged in the removing and reinstallation process. This defeated the purpose for conducting tests. Since methods and equipment have been developed to conduct in-place tests on snubbers, taking advantage of these developments could result in minimizing the damage to snubbers caused by remcyal and reinstallation plus time and cost savings to the plants.
From these short-comings it was concluded that the snubber surveillance requirements for the Technical Specifications should be revised.
The revised surveillance requirements correct these deficiencies in the following manner:
1.
Mechanical snubbers are now included in the surveillance program.
2.
No arbitrary snubber capacity is uscd as a limit to the inservice test requirements.
3.
Seal material no longer requires NRC approval. A monitoring program shall be implemented.to assure that snubbers are functioning within their service life.
4 Clearly defined inservice test requirements for snubbers shall be implemented.
5.
In-place inservice testing shall be permitted.
We have reviewed the proposed amendment submitted by the licensee in light of the issues discussed above and find it has incorporated the necessary reouirements of the Standard Technical Specifications for the surveillance of safety-related snubbers and is therefore, acceptable.
3.0 Environmental Considerations We have determined that the amendments do not duthorize a change 3 in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this l
determination, we have further concluded that the amendments involve an l
action whicn is insignif.icant from the standpoint of environmental impact and pursuant to 10 CFR 51.5(d)(4), that an environmental impact statement, or negative declaration and environmental impact appraisal need not be prepared i
in connection with the issuance of these amendments.
4.0 Conclusions We have 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, and (2) such
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r activities will be conducted in compliance with the Commission's regulations and the issuance of the amendments will not be inimical to the common defense
_end security or to the health and safety of the public.
Principal Contributors:
H. Shaw and M. Grotenhuis Dated: November 8,1983 i
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