ML20078P360
| ML20078P360 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/19/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078P354 | List: |
| References | |
| NUDOCS 8311080008 | |
| Download: ML20078P360 (2) | |
Text
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h NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 q~
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- SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 89TO FACILITY OPERATING LICENSE NO. DPR-50 METROPOLITAN EDISON' COMPANY JERSEY CENTRAL POWER AND LIGHT COMPANY PENN5YLVANIA ELEGIRIC COMPANY GPU NUCLEAR CORPORATION THREE MILE ISLAND NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-289 Introduction By letter dated January 21, 1983, GPU Nuclear Corporation (the licensee) requested that the Technical Specifications for TMI-l be changed to provide a 50 psig increase in the allowable setpoints at which the Emergency Core Cooling System (ECCS) injection systems can be manually bypassed during cooldown.
The High Pressure Injection (HPI) bypass and Reactor Building Isolation bypass setpoints would be increased from 1725 to 1775 pounds per square inch gauge (psig). The Low Pressure Injection (LPI) bypass setpoint would be increased from 875 to 925 psig.
The setpoints for which the manual bypasses would be automatically removed on rising reactor system pressure will remain unchanged at 1800 psig for the HPI and 950 psig for the LPI.
Ev al uati on The licensee requests the increases in the maximum allowable bypass setpoints to reduce the potential for inadvertent ECCS actuation during cooldown operations.
The licensee believes that uncertainties in instrument calibrations would make inadvertent ECCS actuation more likely with the currently specified setpoints.
We have reviewed the change and agree that the increases are in the conservative direction to prevent inadvertent ECCS actuation during cooldown and will not affect ECCS operation since the setpoints to automatically reset and actuate the engineered safeguards systems are not changed. We have further evaluated the change to determine if transients or a loss of coolant during cooldown would pose a safety concern with the proposed setpoint changes.
The High Pressure injection System would not be bypassed until approximately four hours after reactor shutdown at which time the decay heat generation rate would be much lower than was assumed for the design basis transients and accidents analyzed in the Final Safety Analysis Report. The LPI would not be bypassed for an additional hour.
Before the ECCS systems are bypassed, sufficient boron is injected into the primary system to precl1de criticality at cold shutdown.
This action protects against recriticality in the event of an overcooling transient.
During cooldown, the operator monitors the reactor coolant saturation margin to prevent :colant boiling and immediately upon loss of saturation margin is instructed to manually actuate ECCS to provide the necessary makeup ccoling 8311080008 831019 PDR ADOCK 05000 P
. water. Since the high containment pressure isolation signal will remain in,
effect, the proposed increase in the Reactor Building Isolation setpoint manual bypass on decreasing pressure should have no effect in protection against any sudden increase in containment pressure and reactor building isolation.
We have, therefore, concluded that the revised ECCS bypass pressures are acceptable and that no new accident is introduced by the proposed setpoint changes.
Environmental Consideration 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 standpcint 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.
Conclusion 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 activities will be conducted in compliance with the Commission'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.
Dated: October 19, 1983 The following NRC personnel have contributed to this Safety Evaluation:
W. Jensen, T. Dunning, D. Wigginton.
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