ML20083R010
| ML20083R010 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 04/03/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20083Q999 | List: |
| References | |
| NUDOCS 8404230421 | |
| Download: ML20083R010 (2) | |
Text
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,.s,j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR' REGULATION SUPPORTING AMENDMENT NO. 23 TO FACILITY OPERATING LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY i
i MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 1.0 Introduction By letter dated February 15, 1983, Northern States Power Company (the licensee) proposed a change to the Technical Specifications (TS) of Facility Operating License No. DPR-22 for the Monticello Nuclear Generating Plant.
The revisions to the Technical Specifications, Section 3.1.C.1, would change the reactor protection system (RPS) power monitoring system setpoint time delays. The amendment would increase the time delays for all three protec-tive trips from 100 milliseconds to four seconds. The proposed change would allow an under voltage, over voltage, or under frequency condition to exist up to four seconds. The present time delays of 100 milliseconds and associated modifications to the RPS. power supply were evaluated by the staff -
and found acceptable in our previous Safety Evaluation dated November 30, 1982.
2.0 Evaluation The time delays in the RPS power supply protective trips are provided to ensure prevention of spurious and unwarranted separation of the RPS buses.
from an abnormal power supply. However, in doing so, the trip values should be chosen so as not to stress the components to be protected. The RPS bus 1
components and the power monitoring system are supplied by General Electric to the licensee. To support the amendment request, the licensee submitted, in.a letter dated April 27, 1983, a report, prepared by General-Electric, j
which provides information to support a maximun four'second time delay for each of the three protective trips, i.e., under-voltage, over voltage, and under frequency. This extension of the electrical protection. assembly time -
delays reflects the conclusion of a study of the RPS bus components.
The proposed change, to four seconds, would increase the stability of the alternate source, supplying the RPS bus power and would prevent premature t
and spurious trips from occurring during routina switching' operations.
Therefore, the' staff finds acceptable the propoti; tiue-delay of four seconds because it'will. prevent spurious and unwarranted trips, and is.
within the rating of the-RPS bus components, as certified by General.
Electric.
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Based on our evaluation, we conclude that the proposed changes to the Technical Specifications, Section 3.1.C.1, provide trip setpoints that adequately protect the RPS bus loads from abnormal power conditions, without causing spurious trips and are, therefore, acceptable.
4.0 Environmental Considerations We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determi-nation, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR 51.5(d)(4), that an environmental impact statement, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
5.0 Conclusions We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operst. ion in the proposed manner, and (2) public such activities will be conducted in compliance with the Comm<ssion'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.
Principal Contributor:
I. Ahmed Dated: April 3,1984