ML20236A237
| ML20236A237 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/08/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236A235 | List: |
| References | |
| NUDOCS 8903160513 | |
| Download: ML20236A237 (4) | |
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g NUCLEAR REGULATORY COMMISSION j
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j WASHINGTON, D. C. 20665 l
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 19 TO FACILITY OPERATING LICENSE NPF-68 AND AMENDMENT NO. 1 TO FACILITY OPERATING LICENSE NPF-79 a
DOCKET NOS. 50-424 AND 50-425 V0GTLE ELECTRIC GENERATING PLANT, UNITS 1 AND ?
1.0 INTRODUCTION
By letter dated March 6,1989, Georgia Power Company, et al., (the licensee) requested a change to the Technical Specifications for Vogtle Electric Generating Plant (VEGP),(TS) to increase for Unit 2 the maximum total pump fl Units 1 and 2.
The proposed change would change the Technical Specification rate for the centrifugal charging pump lines with a single pump running from 550 gpm to 555 gpm. The licensee requested this amendment on an emergency basis, so as not to delay Unit 2 startup.
2.0 EVALUATION The VEGP 1 & 2 centrifugal charging pumps (CCP) are from Pacific Pump. A Pacific Pump outline drawing recommends a maximum pump runout flowrate of 550 gpm.
It has been identified that the Vogtle pumps may have to operate at up to 555 gpm. The two considerations that must be evaluated for this increased runout limitation are the horsepower capability of the motor and the margin between the available and required net positive suction head (NPSH). The 11censee's evaluation follows:
The pump performance curves indicate that the operation of the Vogtle charging pumps at 555 gpm will require a maximum brake horsepower of 680 HP. The charging pump motors are rated at 600 HP with a service factor of 1.15, thus the maximum horsepower for which the motor is designed is 690 HP. Therefore, the motor is capable of 1
providing the horsepower required for pump operation at 555 gpm.
The motor qualified life is based on continuous operation at 690 HP, therefore, this operation does not reduce the motor qualified life.
The charging pump performance curves provide net positive suction head (NPSH) requirements to a maximum flow rate of 555 gpm for pump
- 52233 and to approximately 550 gpm for the other three pumps.
These performance curves show that the NPSH required at 550 gpm is approximately 22 feet for the most limiting pump. Pacific Pump has performed additional testing of this model pump which has demonstrated that the NPSH requirements remain stable through flow rates as high as 555 gpm.
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' By extrapolation of the performance curves, the required NPSH at 555 gpm will not exceed 22 feet. The available NPSH at 555 gpm has been calculated to be in excess of 83 feet. Therefore, there is substantial NPSH margin, and pump operation at 555 gpm is acceptoble.
Based on the evaluation of the CCP motor horsepower capabilities and the available NPSH margin, the licensee concluded that the centrifugal charging pumps are capable of operating at 555 gpm with no damage to the pumps or degradation of pump performance. No special operating precautions or maintenance requirements are necessary to support operation of the pumps at 555 gpm.
The NRC staff has reviewed the above evaluation and concurs with it.
The licensee evaluated loss of coolant accident (LOCA) analyses and determined that the large break LOCA is the limiting LOCA with regard to increased CCP flow. The licensee then evaluated their large creak LOCA analysis assuming an additional 5 gpm flow from each of 2 CCPs. The licensee determined that the peak cladding temperature (PCT) would increase approximately 2*F above its value of 1995.8'F. This is a small increase and aelow the requirement of 2200'F. The licensee has evaluated the effect of increased CCP runout flow to 555 gpm on containment response following a large break LOCA. The licensee fcund an insignificant increase in mass and energy that does not affect the acceptability of the containment response following a large break LOCA.
Therefore, the licensee has concluded that LOCA analyses are still acceptable with an increased CCP runout flow.
The NRC stdff has reviewed the above evaluation and finds that increased CCP runout flow to 555 gpm is acceptable with regards to LOCA analyses.
The licensee has also reviewed non-LOCA analyses and determined that increased CCP runout flow to 555 gpm does not affect them. The NRC staff finds this acceptable.
In conclusion, the licensee has evaluated the effect of increasing CCP runout flow from 550 gpm to 555 gpm on CCP performance, LOCA analyses, and non-LOCA dnalyses and finds the increase acceptable. The NRC staff has reviewed the licensee's evaluations and finds them acceptable.
Therefore, the NRC staff finds the proposed change to TS 4.5.2.h.1)b) to be acceptable.
3.0 FINAL NO SIGNIFICANT HAZARDS DETERMINATION The state of Georgia was informed by telephone on March 8,1989, of the staff's no significant hazards consideration determination. The State contact had no coments on the determination.
The NRC staff has reviewed the licensee's request for the above amendments in accordance with the standards of 10 CFR 50.92(c) and has determined that
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. should this request be implemented, it would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated because the CCP's performance is not adversely affected by the increase of 5 gpm to maximum runout flow. Also, it would not (2) create t'ne possibility of a new or different kind of accident from any accident previously evaluated because the proposed amendment only changes a flow rate and does not change any structure, component, or system design.
Finally, the proposed amendment would not (3) involve a significant reduction in a margin of safety because PCT is only increased by approximately 2"F and still has over 200'F margin to the limit of 2200*F.
Accordingly, the Comission finds that this request does not involve a significant hazards consideration.
4.0 FINDINGS OF EMERGENCY WARRANTING AN AMENDMENT WITHOUT NOTICE The licensee's application for the TS change has been timely. During the course of reviewing prerequisites for increasing the mode of operation during initial startup of VEGP Unit 2, the licensee discovered on March 2,1989, that a CCP would not meet the flow requirement of TS 4.5.2.h.1)b), and thereby would prevent the licensee from entering Mode 3 scheduled for March 8,1989.
The CCP flow cannot be readjusted and the surveillance re-performed without imposing a significant delay in the startup of VEGP Unit 2.
Therefore, the licensee on March 6,1989, requested the TS revision to increase Unit 2 CCP runout flow by 5 gpm.
The staff finds that failure to grant the proposed change in a timely manner would significantly delay the startup of VEGP Unit 2.
We also find that the licensee could not reasonably have avoided this situation, that the licensee has responded in a timely manner, and that the licensee has not delayed its application to take advantage of the Emergency License Amendments provisions of 10 CFR 50.91. Accordingly, the staff concludes that the licensee has satisfied the requirements of 10 CFR 50.91(a)(5), and that a valid emergency exists.
5.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change in surveillance requirements. The staff has determined 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 exposure. The NRC staff has made a final determination that the amendments involve no significant hazards consideration. 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 i
statement or environmental assessment need be prepared in connection with the i
issuance of the amendments.
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6.0 CONCLUSION
We have concluded, based on the considerations discussed above, that: (1) l the amendments do not (a) significantly increase the consequences of an accident previously evaluated, (b) probability or create the possibility of a new or different kind of accident from any previously evaluated or (c) l significantly reduce a safety margin and, therefore, the amendments do not involve a significant hazards consideration; (2) there is reasonable assurance that the health and s6fety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance l
with the Commission's regulations, and the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Jon B. Hopkins, PDII-3/DRP-I/II Dated: March 8, 1989 l
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