ML20003H206
| ML20003H206 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/20/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20003H203 | List: |
| References | |
| NUDOCS 8105050322 | |
| Download: ML20003H206 (2) | |
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jo, UNITED STATES
.'y 3 7. ( ' j NUCLEAR REGULATORY COMMISSION
.. E WASHINGTON. D. C. 20555 i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 67 TO FACILITY OPERATING LICENSE NO. DPR-29 AND AMENDMENT NO. 61 TO FACILITY OPERATING LICENSE NO. OPR-30 COMMONWEALTH EDISON COMPANY QUAD CITIES STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-254 AND 50-265 Introduction By letter dated September 27, 1977, Comonwealth Edison Company (licensee) proposed a change to the Appendix A Technical Spec.ification for Quad Cities Units 1 and 2 regarding the testing of main steam isolation valve (MSIV) closure time. The proposed change would eliminate the requirement that reactor power be reduced to below 50% of rated power in order to perform the MSIV closure time test.
Discussion and Evaluation The current Technical Specifications require that the MSIV's shall be tested quarterly to verify closure times for each valve. At present it is required that power be reduced to below 50% of rated power to perform the test. The purpose of the power restriction is to ensure that the test not be performed at high power levels, which could result in a Group I containment isolation.
Closure of one MSIV would cause increased steam flow in the remaining open line.
If the isolation trip point is set at 120% flow (as was the case until recently), experience showed that closure of one MSIV could occur at 70% of rated power without tripping the high flow switch. At full rated power, closure of one MSIV would require that the three open lines carry 133% full flow. Recently the Technical Specifications were amended to set the isolation trip pcint at 140% flow, so that at full power, closure of any one MSIV would not cause a Group I isolation from high steam flow.
The 50% power restriction in no way relates to the objective of the test of MSIV closure time and has no technical basis. The only reason for the power limit during the test is to prevent the tripping of the high steam flow containment isolation switch. The proposed removal of the restriction is therefore acceptable.
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. Environmental Considerations We have determined that these amendments do 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 these amendments involve an action which is insignificant from the standpoint of environmental impact, and pursuant to 10 CFR Section 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 these amendments.
Conclusion We have concluded, based on the considerations discussed above, that:
(.1) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and do not involve a signifi-cant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) 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: April 20,1981 l
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