ML20083F932
| ML20083F932 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/04/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20083F917 | List: |
| References | |
| NUDOCS 8401100421 | |
| Download: ML20083F932 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENCMENT N0. 71 TO FACILITY OPERATING LICENSE NO. DPR-25 COMMONWEALTH EDIS0N COMPANY DRESDEN NUCLEAR POWER STATION, UNIT N0.3 DOCKET NO. 50-249
1.0 INTRODUCTION
In a letter dated August 25, 1983, as supplemented November 23, 1983, Commonwealth Edison Company (CECO) (the licensee) proposed to amend Appendix A of Facility Operating License No. DPR-25. The requested amendment changes the safety relief valve actuating setpoint of the Target Rock (TR) valve and the setpoint of two Electromatic Relief (EMR) valves.
A Notice of Consideration of Issuance of Amendment to License and Proposed No Significant Hazards Consideration Determination and Opportunity for Hearing related to the requested action was published in the Federal Register on November 22, 1983 (48 DR 52808). No request for hearing was received and no comments were received. The November 23, 1983 letter merely provides a tabulated format of the valve information submitted by the August 25, 1983 application and is, therefore encompassed within the prenotice published November 22, 1983.
2.0 EVALUATION In response to the Mark I containment design modification program, the licensee discovered that the torus could be subjected to excessive loads if a relief valve actuation occurs shortly after closure.
This loading is the result of a water leg entrapped in the relief valve discharge line from the vacuum caused by the condensed steam in this line. To prevent such loading, subsequent relief valve actuations should be minimized and arso the subsequent actuation time period should be extended.
To accom-olish this objective, the licensee has implemented a ten-second time delay logic to the EMR (203-3B, 203-3C) valves.
The staff approved this same logic modification for Unit 2 in Amendment Nn. 75 to Provisional Operating License DPR-19 dated April 7, 1983.
Tne relief valve. discharge line clears in about 5.6 seconds for the limiting load case.
To minimize subsequent actuations, it is necessary that the pressure setpoint be lowered for two EMR valves so that they are the first to actuate.
In addition, one TR valve pressure setpoint is raised so that it may not actuate durina subseauent actuation. These changes would reduce subsequent actuations and, thus, prevent excessive torus loads.
The EMR valves are the Automatic Depressurization Systen (ADS) valves.
The pressure setpoint channes are rechanical in nature and would not have any inpact on the ADS locic.
The licensee's proposal is, there# ore, acceptable.
8401100421 840104 PDR ADOCK 05000249 P
3.0 ENVIRONMENTAL 00ALIFICATION The. staff has determined that the ar.endment does not authorize a change in-effluent types or total amounts nor an. increase in power level and will not result in any significant envircnmental impact. Having made this determination, the staff further concludes 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.
4.0 CONCLUSION
The staff has 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 activities.will be conducted in compliance with the Conmission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 ACKNOWLEDGEMENT This evaluation was performed by K. Desai.
Dated: January 4,1984 O
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