ML20080N346
| ML20080N346 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 03/01/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20080N334 | List: |
| References | |
| NUDOCS 9503060235 | |
| Download: ML20080N346 (3) | |
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- NUCLEAR REGULATORY COMMISSION.
WASHINGTON, D.C. sesse eeM SAFETY EVALUATION BY THE OFFICE OF' NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 112 TO FACILITY OPERATING' LICENSE NO. NPF-2 AND AMENDMENT NO.103 TO FACILITY OPERATING LICENSE NO.-NPF-8
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SOUTHERN NUCLEAR OPERATING COMPANY. INC.
JOSEPH M. FARLEY NUCLEAR PLANT. UNITS l'AND 2 b
DOCKET NOS. 50-348 AND 50-364.
1
1.0 INTRODUCTION
By letter dated December 19, 1994, Southern Nuclear Operating Company (SNC or
.the licensee) proposed license amendments to change the Technical Specifications (TS) for the Joseph M. Farley Nuclear Plant, Units l' and 2 (Farley). The proposed' changes will (1) increase the as-found tolerances for the main steam safety valve (MSSV) setpoints from the. current i I percent to i 3 percent and (2) revise the high neutron flux setpoints under conditions when 2 or 3 MSSVs are inoperable.
In addition, Bases Section 3/4.7.1.1, Safety Valves, has been updated to ref' lect these changes, and an unrelated editorial correction has also been made to Bases Section 3/4.7.1.2. At Farley there is a total of 15 MSSVs per unit (i.e., five per main. steam line), each set at increments that range from 1075 psig to 1129 psig.
j 2.0 EVALUATION 2.1 MSSV Setooint Tolerances The requested changes revise TS 3/4.7.I'.1 to increase the MSSV setpoint tolerance ranges from i 1 percent to.i 3 percent to accommodate setpoint drift that may occur with these valves during plant operation.
SNC reviewed the increased MSSV setpoint tolerance with respect to the accident analyses presented in the Farley Final Safety Analysis Report (FSAR). The licensee's submittal included the results of evaluations of the proposed chcnge for loss-of-coolant accident (LOCA), non-LOCA and steam generator tube rupture (SGTR) events. The licensee concluded the proposed change will not adversely affect the pressure boundary integrity or safety function of the valves. The
.l evaluation demonstrates that the acceptance criteria of the accident analyses continues to be met.
The. licensee has determined that the proposed TS changes do not result in a significant reduction in the margin of safety. The limiting transient 1n each accident category has been analyzed to determine the effect of the change in i
the setpoint tolerances. Further, in order to prevent the setpoints from drifting outside the i 3 percent range,'SNC will continue to require MSSV i
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setpoint tolerances to be restored to i 1 percent when the as-found lift setting exceeds i 1 percent prior to declaring the MSSVs operable. This will prevent excessive setpoint drift that would cause the peak system pressures to exceed the allowable limits.
The staff has reviewed the licensee's submittal and agrees with their conclusion that the analysis demonstrates the-acceptability of the proposed TS changes. The proposed increase in the setpoint tolerances of the MSSVs has been shown to be acceptable for meeting the plant design basis. Also, for 1
those occurrences where the as-found setpoints of MSSVs are in excess of i 1 percent, resetting to within i 1 percent of the nominal setpoint will be required prior to declaring them operable. Therefore, these proposed TS i
changes have no significant safety impact on the operation of Farley and are acceptable.
2.2 Neutron Flux Hiah Setooint With-Inocerable MSSVs Westinghouse has determined that the maximum allowable power range neutron flux high setpoints given in TS Table 3.7-1 may not be low enough to prevent a secondary side overpressurization during a loss of load / turbine trip.
In Nuclear Safety Advisory Letter (NSAL)94-001, dated January 20, 1994, Westinghouse reported their determination that the maximum allowable initial power level is not a linear function of available MSSV relief capacity.
It was further determined that the current TS provisions for reduced reactor power levels with inoperable MSSVs mey not preclude the secondary side pressure from exceeding 110 percent of its design value during a loss of main feedwater transient, particularly at lower power levels. The NSAL 94-001 also provided the licensee with an option to perform a plant specific analyses of the loss of load / turbine trip (LOL/TT) event to analytically determine the maximum allowed power level for a given number of inoperable MSSVs.
The licensee has performed a plant specific analyses of the LOL/TT event for Farley in accordance with the guidance contained in Westinghouse NASL 94-001 to determine the acceptable maximum reduced power levels'for operation with 1, 2 or 3 inoperable MSSVs per loop. The plant specific analyses resulted in high neutron flux reactor trip setpoint values of 87 percent, 48 percent, and 28 percent of rated thermal power for a maximum of one, two, and three inoperable MSSVs, respectively, on any operating steam generator. These values are the same as or less than the corresponding current TS values of 87 percent, 65 percent and 43 percent for the same conditions.
The staff has determined that the plant specific analyses perfomed in accordance with the Westinghouse guidance ensures that the maximum power level allowed for operation with inoperable MSSVs is below the hekt-removing capability of the operable MSSVs. This ensures that the secondary system pressure will not exceed 110 percent of its design value.
In addition, the new setpoints are more conservative than the previous setpoints. Therefore, the staff finds that the proposed changes to TS Table 3.7-1 and Bases 3/4.7.1.1 are acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the State of Alabama official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The 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. The NRC 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 (60 FR 505). 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.
5.0 CONCLUSION
The Commission 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 the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
B. Siegel C. Liang G. Hammer Date: March 1, 1995
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