ML20086E528
| ML20086E528 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/13/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20086E519 | List: |
| References | |
| NUDOCS 9112020153 | |
| Download: ML20086E528 (3) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR RFACTOR PEGULATION RELATED TO AMENDMENT NO. 7 TO FACILITY OPERATING LICENSE NO. NPF-87 TEXAS UTILITIES ELECTRIC COMPANY, ET AL.
COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 1 DOCKET NO. 50-445
1.0 INTRODUCTION
By application dated October 1, 1991, Texas Utilities Elactric Company (the licensee) requested changes to the Technical Specifications (Appendix A to facility Operating License No. NPF-87) for the Comanche Peak Steam Electric Station, Unit No. 1 (CPSES).
The proposed changes would revise Technical Specification (TS) Surveillance 4.5.2.h, paragraphs (1)(a) and (2)(a), by lowering the minimum centrifugal charging pump (CCP) and high head safety injection (HHSI) pump flow rate surveiliance acceptance criteria.
The purpose of this change is to avoid pump operation at flow rates exceeding runout limits for the pumps.
2.0 EVALUATION In the October 3,1991, submittal, the licensee identified that CPSES CCP and HHS1 pump flows could exceed their runout limit when aligned to take suction from the low pressure injection pump discharge in the recirculation mode of emergency core cooling system (ECCS) operation.
This could lead to pump damage and/or compromise of ECCS safety function.
The licensee indicates that the previous TS minimum flow limits (total CCP flow = 333 gpm, excluding the highest injection line flow; total HHSI pump flow = 437 gpm, excluding the highest injection line flow) are too high to ensure that runout limits (Lotal CCP flow = S60 gpm, total HHSI pump flow = 67S gpm) would not be reachec.
The propused Technical Specification addresses the runout concern by reducing the settings.f injection line throttle valves, resulting in reductions in the l
minimum flow values to 245 gpm total for the CCPs and 400 gpm total for the l
HdSI pumps.
These criteria for avoiding runout were established by the Westinghouse Electric Corporation, which designed the ECCS, with concurrence by the Dressler/ Pacific Pumps Company, supplier of the pumps.
The methodologies i
used were similar to those previously used to determine design flows, but considered the newly identified conditions for operation.
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9112O20153 911113 PDR ADOCK 05000445 I
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4.Y 2-The reductions in flow will be implemented through TS Surveillance 4.5.2.h paragraphs (1)(a) and (2)(a).
In performing these surveillances, the ECCS will be rebalanced by resetting the throttle valves on each of the safety injection branch lines from the discharges of the CCPs and the HHSI pumps, as well as the reactor coolant pump seal injection throttle valves.
Lowering the setting on the throttle vglves will reduce the maximum pump flow and provide greater assurance against pump runout, but will also reduce the minimum flow for non runout situations.
The submittal also provided an assessment of the impact of the flow reductions on design analyses for the plant.
For non-LOCA accidents and transients, the licensee's assessment identified four events whose analyses could be affected:
(a) Mass and Energy Release Inside Containment from a Stcamline Break (FSAR Chapter 6.2.1.4), (b) Mass and Energy Release Outside Containment from a Steamline Break, (c) Steamline Break - Core Response (FSAR Chapters 15.1.4 and 15.1.5), and (d) Feedline Break (FSAR Chapter 15.2.8).
For each of these analyses, a Westinghouse evaluation, summarized in the submittal, concluded that the flow reductions would not prevent the ECCS from mitigating the consequences of the events analyzed in the FSAR, and that the conclusions of the FSAR event analyses remain valid.
For LOCA analyses, the licensee's submittal provides an assessmenc of the impact of the flow reductions on the calculated peak cladding temperature (PCT).
The impacts of the flow reductiont were added to those from other changes to the analyses of record and assessed against the PCTs for the analyses of recnrd.
The estimated changes due to ECCS flow reduction for small break LOCAs is 64.85 F, with 182.2 F for othar changes to the PCT of record, and a resulting small break LOCA PCT of 2034.55 F.
For large break LOCAs these valut> are 0 F effect due to flow reduction, 55 F due to other changes to the PCT of c
record, and a resulting' PCT of 2065.7 F, The=e values meet 10 CFR 50.46(b)(1).
Based on the information provided by the licensee, the staff concludes that with reduced CCP and HHSI flow, the CPSES.-Unit 1, will continue to meet applicable performance criteria, and that the proposed TS changes are acceptabl(.
With regard to the significant changes to the ECCS record of analyses, by letter of July 31, 1991, the licensee committed to provide reanalyses of the LOCA analyses performed with models conforming with 10 CFR 50, Appendix B, by May 29, 1992, thereby satisfying the requirements of 10 CFR 50.46.
3.0 STATE CONSULTATION
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.
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4.0 ENVIRONMENTAL CON;10 ERAT 10N The amendment chang 65 e ;Jrveiller. : rc;uirement.
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 the,e has been no public comment on such finding (56 FR 50956).
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 Contributor:
F. Orr, SRXB/NRR Date:
November 13, 1991
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