ML20205E089
| ML20205E089 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 10/11/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20205E085 | List: |
| References | |
| NUDOCS 8510170198 | |
| Download: ML20205E089 (3) | |
Text
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'o UNITED STATES
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N NUCLEAR REGULATORY COMMISSION 5
j WASHINGTON, D. C. 20555
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SAFETY EVALUATION AMENDMENT NO. 1 TO NPF-40 RIVER BEND STATION DOCKET NO. 458 Introduction By letters dated September 24, 1985 and September 25, 1985, Gulf States Utilities Company (the licensee) requested an emergency change to Section 4.8.1.1.2(f)(3) of the River Bend Unit 1 Technical Specifications. The Technical Specifications currently required an 18-month surveillance of the high pressure core spray (HPCS) diesel generator (IC) to demonstrate its ability to reject a full load of 2500:-
2600 kW without tripping and without exceeding a transient generator voltage of 4784 volts during and following the load rejection. The 4784 limit volts is 115 precent of the rated steady state voltage of 4160 volts. The proposed change is to revise the surveillance test to verify that the transient generator voltage shall not exceed 5400 volts (approximately 130 percent of the rated steady state voltage).
Evaluation In its September 24, 1985 letter, the licensee sta'ed that the River Bend Station HPCS electrical system is designed for a maximum transient voltage overshoot of 5824 volts following a full load rejection. This is 140 percent of rated steady state voltage (4160 volts). The only time the HPCS diesel generator would see a full load rejection is following a trip of the HPCS diesel generator main output breaker. Therefore, only the electrical wiring and components on the HPCS diesel generator side of the main output breaker would be subjected to this transient over-voltage.
It is these loads which l
the licensee ~has verified are designed to withstand 140 percent of rated steady state voltage without any degradation. There is therefore a 10 percent margin between the designed steady state voltage of these loads and the proposed new transient over-voltage limit.
The licensee's HPCS diesel generator voltage regulator has been set to provide optimum perfonnance during starting, loading, and. load rejection transients.
Although this optimization results in a voltage overshoot in excess of that currently allowed in the Technical Specifications,.it is still within the design limit. The staff therefore finds that the proposed change is necessary for operational flexibility in surveillance testing and provides an adequate safety margin to the design voltage limit of the associated components. lhe proposed change is therefore acceptable.
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Emergency Circumstances The proposed change falls into the category of an emergency change since the startup schedule for River Bend Unit I will be delayed unless the NRC takes action to approve the proposed change. Without the proposed amendment, River Bend, Unit I cannot continue its startup test program beyond initial criti-cality because surveillance requirement 4.8.1.1.2(f)(3) needs.to be satisfied to demonstrate operability of the HPCS diesel generator, which in turn is needed before entering Operational Mode 2 or initial criticality.
We have reviewed the facts concerning this request and conclude that the licensee has made a timely submittal and that reactor startup cannot continue beyond initial criticality without NRC action. Also, the licensee did not learn of the need for the proposed change until the recent baseline testing of the HPCS diesel generator on September 15, 1985.
Final No Significant Hazards Determination The Comission has provided certain examples (48 FR 14870) of actions likely to involve significant hazards considerations. Based on the review of the licensee's submittal, as described herein, the staff has made a final deter-mination that the licensee's proposed amendment does not involve a significant hazards consideration since the operation of River Bend Station, Unit I with the proposed change would not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated because there is no change in the design or perfonnance of plant systems or components from those evaluated in the FSAR.
(2) Create the possibility of a new or different kind of accident from any previously evaluated because the proposed amendment does not change any previously reviewed and approved description or analysis provided in the FSAR.
(3) Involve a significant reduction in the margin of safety because operability, availability, and reliability of HPCS diesel generator is not changed by the proposed amendment.
Accordingly the staff has made a final determination that this license amendment involves no significant hazards consideration.
Staff Consultation In accordance with the Commission's regulation, consultation was held with the State of Louisiana by telephone on September 24, 1985. The State has no comments on this action.
Environmental Consideration This amendment changes surveillance requirement 4.8.1.1.2(f)(3). We have determined that the amendment involves 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 Conmission has made a final determination that this amendment involves no significant hazards considerations. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in10CFR51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessnent need be prepared in connection with the issuance of this amendment.
Conclusion The staff has concluded, based on the considerations discussed above, that:
(1) this license amendment involves no significant hazards considerations; (2) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manner; and (3) public such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Dated: OCT 115E5 I
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