ML20059N612
| ML20059N612 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 10/04/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059N611 | List: |
| References | |
| NUDOCS 9010170003 | |
| Download: ML20059N612 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 50 TO FACILITY OPERATING LICENSE NO. NPF-47 GULF STATES UTILITIES COMPANY RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458 INTRODUCTION By letter dated August 22, 1990, Gulf States Utilities Company (GSU) (the licensee) requested an amendment to Facility Operating License No. NPF-47 for the River Bend Station, Unit 1 (RBS).
The proposed amendment would revise Technical Specification (TS) 3/4.7.1.2, " Ultimate Heat Sink," to increase the allowable ultimate heat sink temperature from 82'F to 88*F.
The proposed change would allow GSU to use the ultimate heat sink to cool plant equipment when it is necessary to remove the normal service water system from service for required maintenance and when normal service water temperature nears its design limit of 95'F and adequate temperature differentials are unobtainable.
EVALUATION The ultimate heat sink is designed to provide sufficient cooling water to permit safe shutdown and cooldown of the plant when normal cooling towers are unavailable.
Regulatory Guide (RG) 1.27 requires that sufficient conservatism be provided to ensure that a 30-day supply of water is available.
l The adequacy of the ultimate heat sink at RBS was previously reviewed by the NRC staff in the safety evaluation reports as documented in NUREG-0989 and its t
l Supplement Nos. I and 2.
Using the same methodology, the licensee reanalyzed the impact of the increased ultimate heat sink basin temperature.
The assumption of a delayed 2-hour fan start used in Supplement 2 was adopted.
The heat load requirement as a function of time was assumed to be the same.
In order to meet this requirement, the cooling tower return water temperature was recalculated l
to be lower than the design basis service water inlet temperature of $5*F, which l
was the value assumed for evaluation of the containment heat remova's systems I
and the residual heat removul heat exchanger.
In the previous safety evaluation report, Supplement 1 to NUREG-0989, it was stated that the staff's contractor, Argonne National Laboratory (ANL), calculated maximum cooling tower return l'
water temperature was 89.9'F, which provided a comfortable margin for the required 95'F.
Based on the basin temperature of 88'F, the licensee recalculated the maximum cooling tower return water temperature to be 92'F, which still provides suf ficient margin for the required 95*F.
9010170003 901004 DR ADOCK 0500 9
2-Furthermore, assuming the basin water temperature of 88'F, the licensee recalculated the amount of water available from the basin at the end of 30 days following a design-basis accident.
Assuming the same meteorological i
conditions used in the previous analyses, the licensee calculated that the maximum loss of basin water from drift, natural, and forced evaporation and leakage would be 6,039,000 gallons of water.
This loss resulted in 409,600 gallons of water remaining at the end of the 30-day period.
Although there would be less water available compared to the previous analysis, it still provides sufficient margin for the requirement of 30-day water supply.
Based on the licensee's reanalysis, the maximum cooling tower return water y
g temperatures remain below the design basis service water inlet temperature of 95'F, and the 30-day supply of basin water is satisfied.
Therefore, the staff concludes that the plant still meets the requirements in RG 1.27 even with the increased basin temperature of 88'F and that the proposed TS changes to increase the ultimate heat-sink temperature from 82*F to 88"F are acceptable.
ENVIRONMENTAL CONSIDERATION The amendment involves a change in a requirement with respect to the installation or 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 tnat the amendment involves no significant increase in the amounts, ano no signi-ficant change in the types, of any effluents that may be released offsite, and I
that there is no significant increase in individual or cumulative occupational radiation exposures.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 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 amendment.
CONCLUSION 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 not bc endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
The staff therefore concludes that the proposed changes are acceptable.
. Dated:
October 4, 1990 Principal Contributor:
C. Li, SPLB
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