ML20084Q826
| ML20084Q826 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/01/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20084Q821 | List: |
| References | |
| NUDOCS 8405210509 | |
| Download: ML20084Q826 (2) | |
Text
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UNITED STATES g
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g NUCLEAR REGULATORY COMMISSION 3(
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%,.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 24 TO FACILITY OPERATING j
LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 1.0 Introduction I
By letter dated September 10, 1982, as revised on July 29, 1983, i
Northern States Power Company (the licensee) proposed changes to the i
Technical Specifications of Facility Operating License No. DPR-22 for i
the Monticello Nuclear Generating Plant. The revisions to the Technical Specifications would allow plant operation with a vent or drain valve in the scram discharge volume to be inoperable and the redundant valve operable.
2.0 Discussion 4
The safety function of the scram discharge volume vent and drain valves is to limit the loss of reactor coolant leaka drive seals while the scram valves are open. ge past the control rod The scram valves remain.
open during the interval from scram initiation to the resetting of the scram signal.
3.0 Evaluation The licensee has modified the scram discharge system to include two scram discharge volumes each with two vent and drain valves, as compared with the single vent and drain valve configuration in the
. original system design. The purpose of the proposed changes in Sections 3.3/4.3 of the Technical Specifications is to account for the redundancy and diversity added to the system by the modification.
The proposed changes do not require that the plant be shut down if one of 4
the valves is inoperable.-
The proposed change allows plant operation with one valve inoperable and the redundant valve operable. The operability 'of-the redundant valve -
(operable) will-be verified daily for a period not to exceed seven days.
l Plant operation will' also be permitted if the inoperable valve or the associated redundant valve is maintained in the closed position with the provision that periodically the inoperable and the redundant valve e405210509 840501 7"
PDR ADOCK 05000263 P-PDR
. may both be in the open position to allow draining of the scram discharge volume. The plant can be in this condition for a period not to exceed seven days.
If neither of the above conditions can be met, the plant is required to be at hot shutdown within ten hours.
The proposed changes in Section 3.3/4.3 of the Technical Specification are consistent with the staff guidelines as stated in the December 1, 1980 BWR Scram Discharge System Safety Evaluation, and do not represent a reduction in the ability of the system to perform its safety function, since the integrity of the scram discharge system can be maintained by the redundant drain or vent valve. Thus, we conclude that the proposed changes to Section 3.4/4.3 of the Technical Specifications are 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 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 environ-mental impact statement, 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 assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activicies will-be conducted in compliance with the Commission's regulations and the issuance of the amendment will net be inimical to the common defense and security or to the health and safety of the public.
~
Principal contributor:
T. Chan Dated: May 1, 1984