ML20080K310
| ML20080K310 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/30/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20080K301 | List: |
| References | |
| NUDOCS 8309290101 | |
| Download: ML20080K310 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.60 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLEDO EDISON COMPANY AND CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346 1.0 Introduction By letter dated October 14,1982 (No. 862), the Toledo Edison Company (TED) submitted an application for amendment to Facility Operating License NPF-3 for the Davis-Besse Nuclear Power Station', Unit No.1.
Item 1 of the application proposes modification to pemit revised setpoints for the pressurizer electromatic relief valve and code safety valves.
The Davis-Besse pressurizer is equipped with two spring-loaded code safety valves to relieve high pressure conditions in the reactor coolant system (RCS). Each of these safety valves is desigr.ed for a steam flow of 336,000 lbs/hr.
In the original configuration, there was as much as 35 feet of piping between the pressurizer and a safety valve. TED has eliminated this intennediate piping and has relocated the safety valves directly on the pressurizer.
2.0 Description For the original configuration, TED allowed for a full-flow pressure drop in the intermediate piping of 65 psi. Thus, to have a safety valve stay open until full-flow conditions for an RCS pressure of no more than 2500 psig, the setting on the safety valves had to be 65 psi lower, o.c 2435 psig. Thus, a safety valve would initially open (under no flow conditions) at an RCS pressure of 2435 psig, but as the flow through the intermediary piping increased and the consequent pressure drop increased, the RCS pressure would go up to a maximum of 2500 psig.
With the relocation of the safety valves directly on the pressurizer and the elimination of the 65 psi drop, TED is requesting that the nominal Technical Specification safety valve setpoint be increased from 2435 psig to 2500 psig.
With the +1". tolerance, which is presently
- allowed, TED requests that the Technical Specification setpoint for safety valves located on the pressurizer be < 2525 psig.
f 8309290101 830830 PDR ADOCK 05000346 P
2-TED is also requesting that with this change in the location of the safety valves, the allowable value for a channel calibration check of l
the relief setting of the power operated relief valve (PORV) be raised frca 2385.5 to 2390 psig.
3.0 Evaluation With the safety valves installed directly on the pressurizer, the RCS pressure under full design flow conditions will be the same as the RCS pressure at which a safety valve opens.
Therefore, the nominal Technical Specification setpoint for the safety valves can be 2500 psig. With the
+1% tolerance, the Technical Specification setpoint for safety valves Tocated on the pressurizer can be written as < 2525 psig.
The PORY on the pressurizer has a Technical Specification relief setpoint of 1 2390 psig.
Since the primary purpose of the PORY pressure relief is to prevent the opening of the safety valves, it is desirable to have as large of a differential as possible between the PORY setpoint and the safety valve setpoint.
Increasing the safety valve setpoint by 65 psi will also increase this differential pressure by 65 psi, i.e., from 45 psi to 110 psi. Therefore, the allowable pressure for a channel calibration check of the PORY relief valve can be increased by 4.5 psi, i.e., from 2385.5 to 2390 psig, and the differential pressure between the PORY and the safety valve setpoints will still be increased by 60.5 psi with this change.
Since tne proposed Technical Specification will confonn to the present safety limits, no additional accident analyses are necessary.
Therefore, based on the above evaluation, we find that with the safety valves installed directly on the pressurizer, Section 3.4.3 of the Technical Specifications can be written as follows:
"All pressurizer code safety valves shall be'0PERABLE with a lift setting of < 2525 psig*. When not isolated, the pressurizer electroiiiatic relief valve shall have a trip setpoint of > 2390 psig and an allowable value of 1 2390 psig.**"
- The lif t setting pressure shall correspond to ambient conditions of the valve at nominM operating temperature and pressure.
- Allowable-value for channel calibration check.
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3-4.0 Environnental 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 evironmental impact. Having made this determination, we have further concluded 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 ceclaratfor and environ-mental impact appraisal need cet bo prep 3*ad in connection with the issuance of this amendment.
5.0 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 Commis-j sion'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: August 30, 1983 The following NRC personnel have contributed to this Safety Evaluation:
E. Lantz 1
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