ML20080L883
| ML20080L883 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 02/02/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20080L875 | List: |
| References | |
| NUDOCS 8402170080 | |
| Download: ML20080L883 (2) | |
Text
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f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 22 TO FACILITY OPERATING LICENSE N0. OPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET N0. 50-263 1.0 Introduction By letter dated September 24, 1982, as revised on September 29, 1983, Northern States Power Company (the licensee) proposed changes to the Technical Specifications (TS) of Facility Operating License No. DPR-22 for the Monticello Nuclear Generating Plant. The revisions to the Technical Specifications would add new limiting Conditions for Operation and Surveillance Requirements for the Residual Heat Removal System (RHR) in the Shutdown Cooling Mode.
The proposed changes would specify isolation setpoints to protect the low pressure piping which supplies water to cool the reactor when it is cooling down or shutting dcwn. These setpoints will permit iniection of cooling water only when reactor vessel pressure is less than the RHR cut-in permissive setpoint.
Other changes reauested in the September 24, 1982 submittal are still under staff review and will be addressed by separate Safety Evaluation and license amendment.
2.0 Background and Discussion RHR shutdown cooling supply isolation valves (M02029 and M02030) logic circuitry has been tested by the licensee for many years.
The testing has been performed as a non-technical specification required surveillance. This reauested change formalizes operability and surveil-lance testing under Technical Specification requirenents.
3.0 Evaluation Pressure switches PSs 2-128 A and B sense the reactor pressure ir. the "B" reactor recirculation loop and provide an interlock to prevent the shutdown cooling supply isolation valves (M02029 and MD2030) from opening unless the reactor pressure is below the design pressure of the 05000 b C
PDR I
,- RHR shutdown cooling supply line. The licensee proposed a set pressure of 75 psig for the pressure switches described above. The original design pressure of the piping was 82 psig. Later the licensee reviewed the system for internal pressure, thermal loading and seismic loading conditions in response to IE Bulletin 79-14.
Subsequently, during a conference call, the licensee verified that the maximum allowable pressure of the pipin The maximum setpoint of 82 psig (g is 215 psig. including 7 psig deviation) permissible isolatio is well below the maximum allowable pressure of 215 psig of the shutdown cooling system supply piping.
Morcover, there is a relief valve, RV 2031, on the RHR pump suction piping for protection of the pump and the piping. This relief valve is set at 150 psig, which is lower than the maximum allowable pressure of:215 psig.
Since there is sufficient margin in the proposed set pressure (75 psig) and the maximum allowable pressure (215 psig), the change is acceptable.
- 4.0 Environmental Considerations We have determined that the amendment does not authorize a chance in effluent types or total amounts nor an increase in power level ind will not result in any significant environmental impact.
Having made this determination, 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 state-ment, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendment.
5.0 Conclusions We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurar,ce that the health and safety of the
.public will not be 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 anendment will not be inimical to the common defense and security or to the health and safety of the public.
i Principal Contributor:
G. Thomas Dated:
February 2,1984 l
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