ML20071N421
| ML20071N421 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/27/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20071N419 | List: |
| References | |
| NUDOCS 9408050282 | |
| Download: ML20071N421 (3) | |
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i UNITED STATES
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i SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 190 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLED0 EDISON COMPANY CENTERIOR SERVICE COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION. UNIT NO. 1 DOCKET NO. 50-346 i
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1.0 INTRODUCTION
i In a letter to the Nuclear Regulatory Commission dated February 17, 1993, Centerior Energy, the licensee for the Davis-Besse Nuclear Power Station (DBNPS), requested a revision to Operating License NPF-3 by incorporating revised setpoints and allowable-values to Technicai Specifications (TS) for process instruments of the safety features actuation system, steam and feedwater rupture control system, and the ;ontainment radiation monitoring system.
As a part of the Design Bases Reconstitution Program at DBNPS, the licensee has revised existing setpoint-calculations.
The revised calculations address instrument loop uncertainties that may-not have been included in the original calculations.
The revised calculations included new values for the setpoint and the allowable-value, therefore, a revision to the TS to incorporate the new setpoints and allowable-values was necessary.
The TS-specified trip setpcint for high radiation in the containment is l
being revised from its present value of "<2 x Background at RATED THERMAL POWER" to a new value of "<4 x Background at RATED THERMAL POWER." The increased trip setting provides an additional margin to accommodate normal background radiation changes in the containment.
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2.0 PROPOSED TS-CHANGE Table 3.3-4, Safety Features Actuation System Instrumentation Trip Setpoints i'
Functional Unit - a, Containment Radiation:
Change TRIP SETP0 INT from
"<2 x Background at RATED THERMAL POWER" to "<4 x Background at RATED THERMAL POWER," and ALLOWABLE VALUE from "<2 x Background at RATED THERMAL POWER" to "<4 x Background at RATED THERMAL POWER"."
3.0 EVALUATION The staff noted that the request to change the containment radiation high setpoint was due to a reevaluation of the analysis for determining the trip setpoint. The selection of trip setpoints is such that adequate protection is provided when all sensor and processing time delays are taken into account. To allow for calibration tolerances, instrument uncertainties, and instrument drift, trip setpoint allowable values are conservatively adjusted with respect to the analytical j
limits. Operation with a trip setpoint less conservative than the nominal trip setpoint, but within its allowable value, is acceptable, provided that the difference between the nominal trip setpoint and the j
allowable value is equal to or greater than the drift allowable assumed for each trip in the transient and accident analysis.
A channel is inoperable if its actual trip setpoint is not within its allowable value.
Based on the information provided, the staff concludes that in order to provide adequate protection the setpoint needs to be changed. Taking into consideration all sensor and processing time delays, calibration i
tolerances, instrument uncertainties and instrument drift, the staff concludes that a change of the setpoint and allowable value from "<2 x Background at RATED THERMAL POWER" to "<4 x Background at RATED THERMAL POWER" is warranted.
Based on the above evaluation, the staff concludes that the proposed TS change is consistent with the containment isolation actuation setpoint criteria of NUREG-0737, TMI Action Plan, Item II.E.4.2 for ensuring appropriate isolation on high-radiation and is, therefore, acceptable.
4.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Ohio State official was notified of the proposed issuance of the amendment.
The State official had no comments.
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5.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (58 FR 34096). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
S. V. Athavale Date: July 27, 1994 i
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