ML20031A680
| ML20031A680 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/15/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20031A677 | List: |
| References | |
| NUDOCS 8109250090 | |
| Download: ML20031A680 (3) | |
Text
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UNITED STATES
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 65 TO PROVISIONAL OPERATING LICENSE NO. DPR-19 g
COMMONWEALTH EDISON COMPANY DRESDEN STATION, UNIT NO. 2-DOCKET NO. 50-237 I
1.0 INTRODUCTION
l By telecopy dated September 4,1981 Commonwealth Edison Company (CECO) requested a technical specification change deleting that portion of Specification 4.5.C.2 that requires that the automatic pressure relief subsystem be demonstrated operable daily upon declaring that the.High Pressure Coolant Injection Systcm inoperable.
This telecopy was con-firmed by letter dated September 4,1981.
2.0 BACKGROUND
Technical Specification 4.5.C.2 requires that:
"When it is detennined that HPCI subsystem is inoperable, the LPCI subsystem, both core spray subsystems, the auto-matic pressure relief subsystem, and the motor operated isolation valves and shell side make-up system for the isolation condenser system shall be demonstrated to be operable _immediately. The automatic pressure relief and motor operated isolation valves and shell side make-up system of the isolation condenser shall be demonstrated to be operable daily thereafter."
On September 3,1981 CECO determined some pipe supports on the Dresden Unit No. 2 HPCI line had been damaged by an earlier water hammer incident.
Upon discovery of the damaged pipe supports CECO declared the HPCI system inoperable and complied with the testing required by Technical Specification 4.5.C.2.Thi testing required the demonstration of the operability of the automatic pressure relief subsystem.
This testing was completed successfully j
on September 3,1981 and the operability of the automatic pressure relief subsysten; was demonstrated by opening each electromatic relief valve dis-charging steam to the torus and reseating the valve.
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Because there have been instances in the past in which relief valves have failed to reseat after opening and because the testing of these valves causes a significant thermal and mechanical shock to the reactor vessel and the suppression chamber (torus), Commonwealth Edison has proposed to delete that portion of the surveillance test that requires the daily testing of these automatic pressure relief g
valves on subsequent days that the HPCI system continues to be inoperable.
3.0 EVALUATION We have reviewed CECO's request and have determined that Commonwealth Edison has adequately demonstrated the operability of the automatic pressure relief subsystem on September 3,1981 and that there is a low probability that the system would become inoperable during the six remaining days that the plant is permitted to remain in operation with the HPCI declared inoperable. We have concluded that the increased probability of having one of the pressure relief valves stick open during the daily testing outweighs the benefits gained by the daily testing and that the safety of the facility will not be adversly affected by deleting the requirement to test these valves daily after the September 3,1981 demonstration of their operability.
During the six days of permitted operation with the HPCI out of service the licensee (CECO) will be required to have two feedwater pumps operating at power levels in excess of 300 MWe and one feedwater pump operating as required below 300 MWe end one additional pump operable.
The operation of these feed pumps providegadded assurance that a high pressure make up capability is availai;le for transients with offsite power available which do not cause isoi stion.
4.0 ENVIRONMENTAL CONSIDERATION
S We have detennined that this 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 this amendment involves an action which is insignificant from the standpoint of environmental 1
impact and pursuant to 10 CFR 651.5(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.
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,j 5.0 CONCLUSI0fi We have concluded, based on the considerations discussed above, that (1) because the amendment doesnot involve a significant increase in the probability or corisequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a signifi: cant hazards consideration, (2) there is e
reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities 4
will be conducted in compliance with the Commission's regulations and J.
the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: September 15, 1981
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