ML20148D462
| ML20148D462 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/27/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20148D461 | List: |
| References | |
| NUDOCS 9705300236 | |
| Download: ML20148D462 (3) | |
Text
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t UNITED STATE 8 s
j NUCLEAR REGULATORY COMMISSION e
WASHINGTON, D.C. 30006-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 87 AND 74 TO FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARD OF SAN ANTONIO CENTRAL POWER AND LIGHT COMPANY CITY OF AUSTIN. TEXAS DOCKET NOS. 50-498 AND 50-499 SOUTH TEXAS PROJECT. UNITS 1 AND 2
1.0 INTRODUCTION
By application dated August 8,1996, Houston Lighting & Power Company, et.al.,
(the licensee) requested changes to the Technical Specifications (TSs)
(Appendix A to Facility Operating License Nos. NPF-76 and NPF-80) for the
-South Texas Project, Units 1 and 2 (STP). The proposed changes would allow the transition from Mode 4 to Mode 3 with the turbine-driven auxiliary feedwater (AFW) pump inoperable and allow a 72-hour period after the entry into Mode 3 to complete all necessary operability testing. The proposed changes are intended to allow the plant to achieve the secondary temperatures and pressures required to perform the post-maintenance and surveillance testing necessary to declare the turbine-driven AFW pump operable. The proposed change would affect TS 3/4.7.1.2, " Auxiliary Feedwater System."
2.0. BACKGROUND The AFW system at each of the STP units consists of three motor-driven AFW pumps and one steam-turbine,-driven AFW pump configured into four independent trains.
Each motor-driven pump and the turbine-driven pump provide 100% of the required capacity to the steam generators, as assumed in the accident analysis.
Each motor-driven pump is powered from an independent Class IE power supply and feeds one steam generator, although each pump has the capability to be realigned from the control room to feed other steam generators. The turbine-driven pump receives steam from, and feeds, the remaining steam generator (Train D).
Like the motor-driven pumps, it can also be realigned to feed (but cannot be supplied steam from) any of the other steam generators. The fact that the STP AFW system design includes four AFW pumps (in lieu of three like most other Westinghouse-designed plants) and the fact that the STP design does not re?) on the turbine-driven AFW pump for its station blackout (SBO) analysis provide the plant-specific basis for the licensee's proposed change.
9705300236 970527 PDR ADOCK 05000498 P
- 3.0 EVALUATION Tier are two basic changes associated with the licensee's proposed TS revisis. The first change would revise Action Statement b. of TS 3.7.1.2 to identify that "The provisions of Specification 3.0.4 are not applicable for entry into Mode 3 for the turbine driven pump." Presently, TS 3.7.1.2 would allow the turbine-driven pump to be inoperable for up to.72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> in Modes 1, 2, and 3.
However, entry into Mode 3 from Mode 4 with the turbine-driven pump inoperable is not allowed by TS 3.0.4 which applies to all the plant TSs unless otherwise stated in the individual TS. On the other hand, the turbine-driven pump cannot be demonstrated fully operable in Mode 4 since. surveillance t+. sting requires one of the tests to be done at a steam pressure of greater
-then or equal to 1000 pounds per square inch gauge (psig). Therefore, testing cannot be performed until the plant is in Mode 3, where steam pressure of at least 1000 psig is available. Thus, the exception to TS 3.0.4 is acceptable because it is necessary to enter Mode 3 to fully demonstrate operability of the turbine-driven pump (currently, the turbine-driven pump is declared operable in Mode 4, prior to entry into Mode 3, if all other surveillance tests. are acceptable). Additionally, TS 3.0.4 still applies to the three motor-driven pumps such that they must be operable before entering Mode 3.
The second change is related to the first change in that the proposed revision would allow 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after entry into Mode 3 to perform the surveillance requirement for the turbine-driven pump. The 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is consistent with the existing TS for an inoperable turbine-driven pump in Mode 3.
The 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is also consistent with NUREG-1431, " Standard Tec%1 cal Specifications, Westinghouse Plants," for an inoperable turbine-driven pump in Mode 3.
However, NUREG-1431 requires that the surveillance test be performed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after reaching 1000 psig in Mode 3.
The 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is based on an AFW system with two motor-driven pumps and one' turbine-driven pump where the turbine-driven pump is relied upon to meet the SB0 Rule, 10 CFR Part 50.63,
" Loss of all alternating current power." At STP, the turbine-driven pump is not relied upon to meet the SB0 Rule.
Therefore, the allowed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to perform the surveillance after entry into Mode 3 is considered at least as conservative for STP as the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> identified in NUREG-1431 is for other Westinghouse-designed plants.
In some instances the proposed changes could be considered more conservative than NUREG-1431 because NUREG-1431 would allow continued ' operation in Mode 3 as long as steam pressure is below 1000 psig.
I.e., according to NUREG-1431, indefinite operation is allowed in Mode 3 without performing the turbine-driven pump surveillance test provided steam pressure remains below 1000 psig.
1000 psig corresponds to a reactor coolant system (RCS) temperature of about 540 degrees Fahrenheit (*F).
Therefore, according to NUREG-1431, operation with RCS temperature between 350*F and 540*F'could continue indefinitely without performing the turbine-driven pump surveillance test to assure operation of the pump. At STP, operation could only continue for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> without performing the test under the same RCS conditions. Thus, under these conditions the STP proposed change can be more limiting.
Based on the STP system design which does not rely on the turbine-I
l 3-driven'AFW pump to' meet the SB0 rule, the staff finds that the proposed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after entry into Mode 3 to perform the required surveillance is adequately conservative and consistent with the remainder of the AFW system TS. The proposed change is, therefore, acceptable.
4.0
SUMMARY
Based on its evaluation, the staff finds that the licensee's proposed changes to TS 3/4.7.1.2 are necessary to perform the required testing of the turbine-driven pump, are consistent with the plant-specific AFW system design at STP, which does not rely on the turbine-driven pump to meet the SB0 Rule, and provide added plant flexibility without any significant decrease in safety.
The staff, therefore, finds the proposed changes acceptable.
5.0 STATE CONSULTATION
In accordance with the Comission's regulations, the Texas State official was notified of the proposed issuance of the amendments. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has 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 j
offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public coment on such finding (61 FR i
44359). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR i
51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
7.0 CONCLUSION
The Comission 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 Comission's regulations, and (3) the issuance of the amendments will not be inimical to the comon defense and security or to the health and safety of the public.
' Principal Contributor:
W. LeFave Date:
May 27, 1997 m
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