ML20070B679
| ML20070B679 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/24/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070B674 | List: |
| References | |
| NUDOCS 9102010125 | |
| Download: ML20070B679 (3) | |
Text
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4 UNITED sTATLs
.l NUCLEAR REGULATORY COMMISSION a
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LNCLOSURE 4 SAFETY EVALUATION BY THE OFFICE Or NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.179 TO FACILITY OPERATING LICENSE NO. DPR-33 AMENDMENT NO.188 TO FACILITY OPERATING LICENSE NO. DpR-52 l
AMEN 0 MENT NO.151 TO FACILITY OPERATING LICENSE NO. OPP-68 i
TENNESSEE VALLEY AUTHORITY BROWh$ FERRY NUCLEAR PLANT, UNITS 1, 2 AND 3 DOCKET NOS. 50-259, 50-?_60 AND 50-296 1
1.0 INTRODUCTION
6 By letter dated August 7, 1990, as supplemented November 30, 1990, the Tennes-see Valley Authority (the licensee) requested changes to the Technical Specifi-cations surveillance requirements for the high-pressure fire pumps installed at Browns Ferry Nucitar plant (BFN),
The following NRC evaluation of the requested changes is based on the review of 4
supporting ju$tification furnished by the licensee in Enclosures 1 through 5 i
of the letter of August 7, 1990.
EVA,LUATION 2.0 V
The fire protection water supply and the raw sarvice water (RSW) system at BFN have a common supply header.
Both distribution systems are normally pressurittd and supplied by the RSW pumps.
In addition to the RSW pumps, there are three electric motor driien and one diesel engine driven high-pressure fire pumps, each capable of supplying the single largest expected fire ficw and RSW demands.
The original specifications for the fire pumps called for a minimum discharge volume of 2500 gpm at discharge head (pressure) of 300 feet (130 psig) for the electric driven pumps and 3t0 feet (147 psig) for the diesel driven pumps.
However, none of the four fire pumps can meet the manufacturer's original design specifications, due in part to system aging and changes in pump drives.
Operation of the fire pumps occurs when a drop in system pressure produces an alarm in the control rocm and signals the control room operators to manually initiate the starting sequence. Once initiated, the sequence proceeds auto-matica11y with each pump starting in turn (electric driven pumps first and the diesel driven pun,p last) wher, the system pressure drops below 120 psig. The sequence has a built.in time delay of 15 seconds between the starting of each pump and the next pump. This delay is provided to protect the system from excessive pressure surges that develop from simultaneous pump starts and to prevent unnecessary multiple pump starts.
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Flow deman'd assumptions used by TVA to determine the highest expected flows i
and therefore the minimum acceptable capacities of their fire. pumps are as,
follows:
i Automatic fire suppression system - 589 gpm assumes operation of all automatic sprinkler heads in the worst 1500 square foot area of the plant.
Manual fire suppression activities - 250 gpm for manual hose lines.
i RSW loads - 1250 gpm for largest expected RSW demand.
Together, these three water demands give a total expected maximum flow demand of 2089 gpm. The licensee initially proposed to round the value to 2100 gpm at 1
130 psig and establish this as the minimum technical specification surveillance requirement. The NRC staff did not agree that 2100 gpm would furnish an adequate margin of safety and recommended that the licensee specify 2250 gpm at 130 psig as the revised TS fire pump surveillance requirement. This value was based on providing sufficient safety margin and represents a degraded condition of 10 percent below the manuf acturer's recomended pump performance.
The TVA letter dated November 30, 1990, with enclosed TS pages, incorporated the staff's recommendation, j
3.0 ENVIRONMENTAL CONSIDERATION
The amendments involve changes to the surveillance requirements.
The staff has i
determined that the amendments invot,ve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released j
offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure, The Commission has previously issued a pro-posed finding that these amendments involve no significant hazards considera-tir and there has been no public comment on such finding (55 FR 36356).
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 nor environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
Based on the above evaluation, we conclude that tne licensee's proposed Technical Specification surveillance requirements for acceptable minimum flow of BFN fire pumps of 2250 gpm at 130 psig are acceptable.
Note, however, that while this change applies to all of the pumps which supply fire protection water for the entire three unit site, justification is based on the ability of the pumps to individually supply the fire protection and raw service water needs for only one unit. The TVA amendment request and the associated NRC safety evaluation have been prepared to support Unit 2 restart.
TVA has not completed fire protection related modifications for Units 1 and 3.
When those modifications are completed, the licensee will perform a similar evaluation of the combined fire protection / raw service water for the entire site.
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The Commission made a proposed determination that the amendments involve no significaht hazards consideration which was published in the Federal Register (55 FR 36356) on September 5 and December 10, 1990 (55 FR 50791) and consulted with the State of Alabama.
No public comments were received and the State of Alabama did not have any comments.
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will nct be endangered by operation in the propcsed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance af the amendments will not be inimical to the common oefense and security nor to the health and safety of the public.
Author:
D. rictiey Date: January 24, 1991 l
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