ML20114A911
| ML20114A911 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/18/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20114A904 | List: |
| References | |
| NUDOCS 9208240099 | |
| Download: ML20114A911 (2) | |
Text
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UNITED STATES i
NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D C. 20066 3
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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 40 TO FACILITY OPERATING LICENSE NO. NPF-76 HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARD OF SAN ANTONIO CENTRAL POWER AND LICHT COMPANY CITY OF AUSTIN. TEXAS DOCKET N0. 50-498 SOUTH TEXAS PROJECT. UNIT 1
1.0 INTRODUCTION
By application dated May 26, 1992, Houston Lighting & Power Company, et. al.,
(the licensee) requested changes to the Technical Specifications (Appendix A to facility Operating License No. NPF-76) for South Texas Project, Unit 1.
The proposed change is a one-time extension of the inspection interval for the turbine valves listed in Technical Specification (TS) 3/4.3.4, " Turbine Overspeed Protection." TS 4.3.4.2.d currently requires inspection by disassembly of at least one valve per category at least once per 40 months.
The revised TS would allow a one-time extension for Unit I until the fifth refueling outage which would constitute an interval of approximately 52 months. Application of the allowable 25 percent extension of TS 4.0.2 would result in an inspection interval of 50 months.
"0 EVALUATION The guidelines in the Standard Review Plan (SRP), Section 10.2 specify that at approximately 3%-year intervals, during refueling or maintenance shutdowns coinciding with the insarvice schedule required by Section XI of the ASME Code, examinations should be conducted on specifically identified turbina valves.
The STP-1 TS Section 4.3.4.2 states that the Turbine Overspeed Protection System shall be demonstrated operable by, among other steps, disassembling at le-ist one of certain specified valves at least once per ao months.
The p rpose of the disassembly and inspection is to ensure th' c ',
steam :mmission valves will not fail to seat as a result of internal ',a e
corrosion.
The NRC acceptance criteria for a fr,orably oriented turbine such as the ole at STP-1 is that the total probability for turbine missile generation must be less than 1.0E-4 per year at the time the turbine is brought on line.
9209240099 920ste PDR ADOCK 05000498 P
' Once the turbine is on line, if the probability exceeds 1.0E-4 per year but remains below 1.0E-3 per year, it may be kept in service until the next scheduled outage, at which time the licensee must take action to reduce the probability to meet the 1.0E-4 per year limit before returning the turbine to service.
The licensee has calculated a probability of turbine missile generaiion of 2E-4 per year for operation at the beginning of the fifth refueling outage.
Further, although valve seat inspections were not performed, two high pressure stop and two governor turbine valves were disassembled and parts replaced during the second refueling outage, which ended in June 1990.
The high pressure turbine stop valve seats were also replaced.
Therefore, there is adequate assurance that the valves till operate properly and that an acceptable margin of safety will be retained.
3.0 STATE r0NSULTAT10N in accordance with the Commission's regulations, the Texas State 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 and changes surveillance requirements.
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 irdividual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no sigrificant hazards consideration, and there has been no public comment on such finding (57 FR 2G202).
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 itith 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 Contributor: George F. Di k, NRR/PDIV-2 Steven R. Jones, NRR/SPLB Date:
August 18, 1992
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