ML20107D428
| ML20107D428 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 02/15/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20107D422 | List: |
| References | |
| TAC-56738, TAC-56739, NUDOCS 8502220381 | |
| Download: ML20107D428 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NOS. 72 AND 65 TO FACILITY OPERATING LICENSE NOS. DPP-42 AND DPR-60 NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT NOS. 1 AND 2 nnevrT wns an_pa? AND 50-306 Introduction By letter dated January 18, 1985, Northern States Power Company (NSP), the licensee, requested amendments to Facility Operating License Nos. DPR-42 and DPR-60 for the Prairie Island Nuclear Generating Plant Unit f;os. I and 2 (PINGP). The Comission has determined that failure to process the pro-posed changes in an expedited manner will result in extending the present Unit I shutdown coincident with the shutdown of Unit 2.
In addition, failure to act in a timely way would result in undesirable plant conditions after Unit I startup. The requested amendments propose a change to the technical specifications (TS) in section 3.3.D.2c dealing with the allowable inoperable period of the coolino water headers of the service water system.
The existing TS allow one of'the two cooling water headers to be out of service for a period not to exceed 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The proposed change would extend the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Evaluation c
The TS tection 3.3.D.2c for the Prairie Islar.d Nuclear Generatine Plant Unit Pos. I and 2 allows one of the two required coolinn water headers to be out o r
service for a period not to exceed 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> provided that the diesel-driven pump and the diesel generator with its associated safety features on the operable header are demonstrated operable.
In addition, both horizontal and vertical motor driven pumps associated with the operable header must also be operable.
These provisions give assurance of the operability of the service water system with one of the redundant headers out of service and are not affected by the pro-posed change (i.e., increasing the out of service period from 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />).
.The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> requirement was intended to allow sufficient time to complete repairs and-testing using safe and proper procedures.
Experience has shown that the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period does not provide adequate time for most repairs, except for minor system maintenance. This is due to the large size of the system and its components, the time needed to prepare the system for repairs and the quality control and ouality assurance that must be maintained throughout the repair period. This has been shown in the detailed planning for the removal of the loose part located in loop A of the Prairie Island cooling water system which requires the removal of the inlet pipe portion of the system in the strainer area in order to rer.ove the loose part.
Extending the inoperable period of the cooling water header to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> could in a small' measure increase the severity of pre-viously analyzed accidents but the change is clearly within all acceptable M""A88n 8388%
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. criteria set forth in the Standard Technical Specifications (NUREG-0452).
In addition, the staff has judged that the reason for only a slight increase in the severity of a previously analyzed accident is that a second parellel system must be operable and tested to the provisions described above and, if it fails, the plant must be brought to cold shutdown. On this basis, the staff finds the proposed change to extend the out-of-service period of the cooling water headers from 24 to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is acceptable.
Final No Sionificant Hazards Consideration Determination On January 30, 1985, the Commission published a notice in the Federal Reaister (50 FR 4285) seeking public comments on its proposed determination that these amendments involve no significant hazards consideration. No public comments were received. The State of Minnesota was consulted on this matter, and had no comments on the proposed determination. As discussed above, extending the out-of-service period of the cooling water headers frcm 24 to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is clearly within all acceptable criteria set forth in the Standard Technical Specifica-tions (NUREG-0452) and the extension results in an insignificant change in the safety analysis. This change dces not involve a significant increase in the probability or consequences of an accident previously evaluated; or create the possibility of a new or different kind of accident from any accident pre-viously evaluated; or involve a significant reduction in a margin of safety.
Therefore, the Commission has made a final determination that the amendments do not involve a significant hazards consideration.
Envircnmental Consideration These amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendments involve no significant increase in the amounts, and r' significant chance in the types, of any effluents that nay be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.2?(c)(9). Purruant to 10 CFR 51.22(b), no environmental impact state-ment or environmental assessment need be prepared in connection with the issuance'of these amendments.
-Date: February 15, 1985 Principal Contributor:
D. C. Di Ianni
.