ML20211P900
| ML20211P900 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/02/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20211P896 | List: |
| References | |
| NUDOCS 9909140131 | |
| Download: ML20211P900 (3) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.115 AND 103 TO FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 STP NUCLEAR OPERATING COMPANY. ET AL.
SOUTH TEXAS PROJECT. UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499
1.0 INTRODUCTION
By application dated June 7,1999, as supplemented by letters dated June 24 and August 24, 1999, STP Nuclear Operating Company (the licensee), requested changes to the South Texas Project (STP), Units 1 and 2, Technical Specifications (TSs). The proposed changes would revise TS 2.0, " Safety Limits and Limiting Safety System Settings," TS 3.2.5, "DNB [ Departure from Nucleate Boiling] Parameters," and the associated Bases, and Administrative Controls l
Section 6.9.1.6, " Core Operating Limits Report [(COLR)]," by relocating cycle-specific reactor coolant system-related parameter limits from the TSs to the COLR.
The August 24,1999, supplement provided revised TS pages and clarifying information that was within the scope of the original Federa/ Register notice and did not change the staff's initial l
proposed no significant hazards consideration determination.
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2.0 BACKGROUND
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Guidance on the relocation of cycle-specific TS parameters to the COLR was developed by the NRC. This guidance was provided to all power reactor licensees and applicants by Generic Letter (GL) 88-16, " Removal of Cycle Specific Parameter Limits from Technical Specifications,"
dated October 4,1988. In addition, the proposed TS changes follow the guidelines presented in WCAP-14483-A, " Generic Methodology for Expanding Core Operating Limits Report," which was accepted for referencing by the NRC staff on January 19,1999.
3.0 EVALUATION The following TS changes are proposed:
1.
TS 2.1," Safety Limits," would be revised to relocate Figures 2.1-1 and 2.1-2 (Reactor Core Safety Limit) to the COLR. The figures would be replaced by TS 2.1.1.1 which would state that in MODES 1 and 2, the departure from nucleate boiling ratio (DNBR) shall be maintained greater than or equal to 1.17 for the WRB-1 DNB correlation and by TS 2.1.1.2 which would state that in MODES 1 and 2, the peak fuel temperature shall be maintained less than 5080 F, decreasing by 58 F per 10,000 MWD /MTU of burnup.
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' Therefore, the figures would be replaced with more specific requirements regarding the safety limits (i.e., the fuel DNB design basis and the fuel centerline melt design basis),
conforming with WCAP-14483-A. We find this proposed relocation acceptable.
2.
TS 2.2, Table 2.2-1, " Reactor Trip System Instrumentation Trip Setpoints,' would be revised to relocate the Overtemperature AT (OTDT) and Overpower AT (CPDT) trip 4
setpoint parameter values to the COLR. The NRC has previously approved COLR additions for relocating the OTDT and OPDT setpoint parameter values to the COLR for the Catawba, McGuire, and Seabrook Nuclear Stations. This allows these setpoints to be based on cycle-specific core design parameters, which are verified on a cycie-specific basis, thereby avoiding the necessity of overly conservative TS limits.
The applicable NRC-approved setpoint methodology, WCAP-8745-P-A, " Design Bases j
for the Thermal Overpower AT and Thermal Overtemperature AT Trip Funct;ons," dated September 1986 (proprietary and nonproprietary reports available), will be added to the i
list of approved analytical methods in TS 6.9.1.6.b. We find the proposed changes acceptable.
3.
TS 2.2, Table 2.2-1, would also be revised to relocate the loop design flow referenced i
by the reactor coolant f'ow-low trip to the COLR. The low reactor coolant flow trips provide core protection to prevent DNB by mitigating the consequences of a loss of flow resulting from the loss of one or more reactor coolant pumps. The value for loop design flow to be relocated to the COLR is the analytical value consistent with the thermal design flow assumed in the DNB analysis. We find the proposed relocation acceptable.
4.
TS 3.2.5, " Departure from Nucleate Boiling (DNB) Parameters," would be revised to relocate the pressurizer pressure and the reactor coolant system (RCS) r2verage temperature (Ty) to the COLR. The minimum measured flow would also be moved from TS 3.2.5 to the COLR. The minimum thermal design reactor coolant flow would be retained in TS 3.2.5. The values of pressure, temperature, and flow rate to be relocated to the COLR are indicated values and include measurement uncertainties. The value for RCS flow rate maintained in TS 3.2.5 is the thermal design RCS flow rate used in the analysis approved by the NRC and is an analytical limit consistent with 10 percent plugging of the steam generator tubes and DNB requirements. Since this minimum value is retained in the TS, any reduction in RCS flow rate due to additional tube plugging or other physical plant change would have to be reviewed by the NRC. This is consistent with WCAP-14483-A. We find the proposed changes acceptable.
5.
TS 6.9.1.6," Core Operating Limits Repor1," would be modified to reflect the above relocations to the COLR and to add the appropriate approved references for the COLR parameters. We find the proposed changes acceptable.
EVALUATION
SUMMARY
The staff has reviewed the proposed TS revisions for STP, Units 1 and 2, and finds them in conformance with NRC GL 88-16 and with WCAP-14483-A and acceptable. Specifically, the revisions would relocate the reactor core limits figures for thermal power, pressurizer pressure and the highest operating loop coolant temperature for TS 2.1 to the COLR. The figures would be replaced with more specific requirements regarding the safety limits (i.e., the fuel DNB design basis and the fuel centerline melt design basis). In addition, the limiting safety system
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settings for reactor coolant flow low loop design flow, the OTDT and OPDT setpoint parameter values for TS 2.2, and the DNB related parameters for RCS T,,, pressurizer pressure, end minimum measured RCS flow (including flow measurement uncertainties) would be relocated to the COLR.
4.0 - - STATE CONSULTATION In accordance with the' Commission's regulations, the Texas State official was notified of the proposed lent:ance of the amendmmts. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change a rdquirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has i
determined that the amendments involve 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 3
significant increase in indvidual or cumulative occupational radiation exposure. The i
Commission has previously issued a proposed finding that the arr endments involve no significant hazards consideration, and there has been no public comment on such finding (64 FR 38036). Accordingly, the amendmants meet the eligibility criteria for categorical
' exclusion set forth in 10 CFR 51.22(c)(9).' These amendments also change in recordkeeping, reporting, or administrative procedures and requirements. Accordingly, with respect to these items, the amendments _ meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(10). Pursuant to 10 CFR 51.22(b), no environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSION
i The Commission has, conclud_ed, 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 Co#nmission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and cccunty or to the health and safety of the public.
Principal Contributor: L. Kopp Date: S ptember 2, 1999 i
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