ML20198K785
| ML20198K785 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/16/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198K777 | List: |
| References | |
| NUDOCS 9812310163 | |
| Download: ML20198K785 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMIS$10N WASHINGTON, D.C. 300es 0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REA CTOR REGULATION RELATED TO AMENDMENT NOS. 91 RAND 46 TO FACILITY OPERATING LICENSE NOS. DPR-66 AND NPF-73 DUQUESNE LIGHT COMPANY OHIO EDISON COMPANY PENNSYLVANIA POWER COMPANY THE CLEVELAND ELECTRIC ILLUMINATING COMPANY THE tot Frio EDISON COMPANY BEAVER VAli FY POWER STATION. UNIT NOS.1 ANQ2 DOCKET NOS. 50-334 AND 50-412
1.0 INTRODUCTION
By letter dated July 13,1998, the Duquesne Light Company (the licensee) submitted a request for changes to the Beaver Valley Power Station, Unit Nos.1 and 2 (BVPS-1 and BVPS-2),
Updated Final Safety Analysis Report (UFSAR) descriptions of the intake Structure main entrance and interconnecting cubicle doors. The current UFSAR descriptions state that the cubicle access doors are open to permit excess water from a major pipe rupture to flow out of the cubicles thereby avoiding intomal flooding. The proposed changes would address a new failure mode of safety-related equipment that had not been previously conside red for BVPS-1.
The proposed changes would state that the cubicle interconnecting flood protection doors are normally closed with their inflatable seals depressurized and that the associated security / fire doors are raormally closed. The proposed door closure arrangement is intended to protect the safety-related equipment in the interconnecting cubicles from the consequences of potential intemal flocding.
The pump intake structure for BVPS-1 and BVPS-2 is shared between the BVPS-1 river water (RW) pumps and BVPS-2 service water (SW) pumps. The pump intake structure has four separate cubicles. The BVPS-1 RW "A" pump is located in the "A" cubicle. The BVPS-1 RW "B" pump and the BVF%2 SW "C" pump are located in "B" cubicle. The BVPS-1 RW "C" pump and the BVPS-2 SW '8 ' oump are located in "C" cubicle. The BVPS-2 SW "A" pump,is in the "D" cubicle. Each cubich has an access entrance equipped with a set of doors which consist of a fuse-link fire protection / security access control and a sliding door equipped with inflatable seals for extemal flooding control. The same types of doors are provided between cubicles "A" and "B" and between cubicles "C" and "D". There is a solid wall and no door bemeen cubicles "B" and "C". It was the licensee's practice to maintain the fuse link fire protection doors and the flood control doors in the normally open positions.
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The potential for intemal flooding and its impact on safety-related equipment / systems in these cubicles has been addressed in BVPS-2 UFSAR. However, this intemal flooding scenario has not been addressed in the current BVPS-1 UFSAR. In the original BVPS-1 safety analyses, potential for intemal flooding in these cubicles was not considered because there were no high energy lines in these cubicles. For plants licensed at the time of BVPS-1, this lack of consideration of the potential for intemal flooding also meant that pipe breaks, even for moderate energy piping located in these cubicles, were not required as part of the design basis. In addition,in the event of a pipe rupture in any of the pressurized waterlines in these cubicles, open cubicle access doors would perrnit water to flow out of the cubicles.
During the course of BVPS 1 and BVPS-2 operation, the licensee changed its practice on cubicle access door arrangement such that the extemal flood protection doors leading into each intake structure pump cubicle are normally open with their associated security / fire door: nonnally closed.
Subsequently, an unreviewed safety question was found as a result of the practice of keeping the intake structure cubicle access doors closed in lieu of open as previously stated in the BVPS-1 UFSAR. Consequently, the licensee per' armed an intemal flooding evaluation and identified that failure of the rubber expansion joints in the BVPS-1' RW system located in one cubicle is a flooding concern for the adjacent cubicle unless the interconnected doors between the cubicles are kept closed. By letter dated July 13,1998, the licensee proposed to revise the BVPS-1 UFSAR to address the potential for intemal flooding resulting from the failure of RW system rubber expansion joints in the pump cubicles, and to establish the closed positions for the intake structure pump cubicle security / fire access doors and the open position for the extemal flood protection doors in the UFSARs for both units.
2.0 EVALUAT!ON As discussed in NRC Integrated inspection Report 50-334/98-09,50-412/98-05, the Resident inspection staff has reviewed the licensee's response to the issue, which was licensee identified, and found it to be acceptable with comprehensive corrective actions.
The licensee performed an evaluation to determine the impact of potential for intemal flooding resulting from the failure of BVPS-1 RW system rubber expansion joints on safety related equipment / systems located in the pump intake structure cubicles. The licensee concluded that,in the event of a failure of an RW system rubber expansion joint in any one of the cubicles, flooding of safety-equipment / systems will be limited to only one RW or SW train in either unM the fire protection / security access and flood control doors between cubicles 'A' and 'B' and between cubicles 'C' and "D" are maintain 6 ' ' the normally closed positions. Therefore, the licensee proposed to maintain the cubicle doors in the following arrangement: the extema! flood protection doors leading into each pump intake structure cubicle are normally open with their associated security / fire doors normally closed, and the interconnecting flood protection doors located between the cubicles are normally closed with their seals depressurized along with their associated security / fire doors normally closed. The flood control door seals will be pressurized in the event of a flood or for seal testing purposes.
1 BVPS-2 service water system employs metal expansion joints.
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i Based on its review of the licensee's rationale and the evaluation, the NRC staff has concluded that maintaining the cubicle security / fire doors and the f;ood control doors between the cubicles containing redundcnt RW and redundant SW pumps in the closed positions does not affect the operation or design of the RW system, SW system or other equipment / systems 6mted in the cubicles. However, it will prevent the common cause failure of these pumps / system. $'* to a failure of a rubber expansion joint in one of the cubicles. Therefore, the NRC staff finds the licensee's proposed change to the BVPS-1 and BVPS-2 UFSARs to establish the cubicle ocors in the above described positions acceptable.
3.0 STATE CONSULTATION
1 in accordance with the Commission's regulations, the Pennsylvania State official was notified of j
the proposed issuance of the amendments. The State official had no comments.
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4.0 ENWRONMENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined
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that the amendments involve 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 amendments involve no significant hczards consideration, and there has been no public comment on such finding (63 FR 43202). 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 environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 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 the health and safety of the public.
Principal Contributors: D. Shum D. Collins Date: December 16, 1998
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