ML20080R436

Safety Evaluation Supporting Amends 34 & 20 to Licenses NPF-87 & NPF-89,respectively

ML20080R436
Person / Time
Site:	Comanche Peak
Issue date:	03/01/1995
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20080R429	List: ML20080R427 ML20080R436
References
NUDOCS 9503090304
Download: ML20080R436 (4)

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j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

-I RELATED TO AMENDMENT NOS. 34 AND 20 TO 4

FACILITY OPERATING LICENSE NOS. NPF-87 AND NPF-89 j

TEXAS UTILITIES ELECTRIC COMPANY t

COMANCHE PEAK STEAM ELECTRIC STATION. UNITS 1 AND 2

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DOCKET NOS. 50-445 AND 50-446-l Li

1.0 INTRODUCTION

R By application dated November.18, 1994, Texas Utilities Electric Company.

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-(TU Electric /the licensee)-requested changes to the Technical Specifications y

_(Appendix A to Facility Operating License Nos. NPF-87 and NPF-89) for the>

8 Comanche Peak Steam Electric Station (CPSES), Units 1 and 2.

The proposed-changes would ~ revise Technical Specifications (TS) 3/4.2.2, " HEAT FLUX HOT,

CHANNEL FACTOR - F,(Z)" and 6.9.1.6, " CORE OPERATING LIMITS REPORT." as follows:

(1) TS Surveillance Requirement'4.2.2.2f would be revised to replace the

.i standard 2 percent-allowance, which accounts for increases in F,'(z) i between surveillances, with cycle-specific allowances in the Core-Operating Limits Report (COLR)._

(2) TS 6.9.1.6a, item 5 would be revised to add the cycle-specific allowance which is added to F,*(z) when F,'(z) is increasing.

'i (3) TS 6.9.1.6b, item 5 would be revised to update the reference to the NRC approved methodology provided in Westinghouse Topical Report WCAP-10216-P-A, Revision IA, " Relaxation of Constant Axial Offset Control - F, Surveillance Technical Specification."

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2.0 BACKGROUND

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l Technical Specification Surveillance Requirement 4.2.2.2e requires that the l

Heat Flux Hot Channel Factor - F,(z) be measured every 31 effective full power i

days (EFPD). A computed Heat Flux Hot Channel Factor - F,*(z) is determined -

i by increasing the measured F (z) to account for manufacturing tolerances and f

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• z) h. (z)~ is used to ensure that F,(z) does not measurement uncertainties ~.

exceed its. limit.

as increased from the previous surveillance, i

Surveillance Requiremen$. (4.2.2.2f requires that either a 2 percent allowance be added to F *(z) and that the increased value of F,*(z) remains within the limits specifled by Specification 4.2.2.2d, or the surveillance frequency must be increased to every 7 EFPD.

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currently, Technical Specification 4.2.2.2f uses a standard 2 percent allowance because it has historically bounded the maximum potential monthly-cincrease in F,*(z) for typical cores. However, for more recent core designs, between monthly surveillances, F,'(z) may increase beyond the 2 percent allowance provided.

For those cores, a larger allowance should be specified

.on a cycle-specific basis' A generic analysis of F,(z) increases was submitted to the NRC by Westinghouse Topical Report WCAP-10216-P-A, Revision -1A.

The NRC reviewed the report and found it to be acceptable for referencing in licensing applications by letter dated November 26, 1993.

a Westinghouse informed the licensee that the Unit 2, Cycle 2 reload could have increases in F,'(z) which exceed 2 percent per month during some portion of the cycle. Therefore, in order that the CPSES TSs use-the appropriate cycle-specific allowance factors, the proposed changes to Surveillance Requirement ~

7 4.2.2.2f and the' administrative controls TS 6.9.1.6a, item 5 and TS.6.9.1.6b, item 5 were submitted for approval.

i 3.0 EVALUATION F

• z) is determined during periodic flux maps and compared to the F *(z)'

.f llm(it to ensure that F,(z) does not exceed the maximum value assumed in the safety analyses.

F (z) normally decreases with increasing burnup because locations of peak p,ower output in the core are also locations of peak depletion rate. However, cores using large numbers of burnable absorbers may show small increases in F,*(z) over some period of core life.

If F *(z) has increased since the last surveillance, a 2 percent allowance is adJed to F,*(z) (as one option permitted by Surveillance Requirement 4.2.2.2f) and the sum must meet the F

• z limit specified in TS 4.2.2.2d.

The 2. percent allewance accounts fo(r) additional increases in F,*(z) that may occur prior.to i

the next monthly flux map. A standard 2 percent allowance was originally selected because it bounded the maximum monthly increase in F '(z) for typical cores (based on Westinghouse analyses of earlier core designs,).

Cores typical of the CPSES Unit 2, Cycle 2 design, with low leakage loading patterns, higher amounts of burnable poisons, and longer cycle lengths may exhibit F *(z) increases in excess of 2 percent per month during some portion of the fuel cycle.

The NRC reviewed Westinghouse Topical Report WCAP-10216-P-A, Revision IA and found it to be acceptable for referencing in licensing applications by letter dated November 26, 1993. As stated in the Safety Evaluation (SE) accompanying that letter, the NRC concluded that revisions to the F,(z) TS surveillance requirements were acceptable for plants using constant axial offset control (CAOC) for power distribution control, provided that:

(1) the new peaking factor penalties are incorporated in the Core Operating Limits Report (COLR),

(2) the new peaking factor penalties are calculated using NRC-approved methods, and (3) the approved version of WCAP-10216-P, Revision IA is included in the Administrative Reporting Requirements Section of the technical specifications.

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CPSES Units 1 and 2 use CAOC for power distribution control and the prop (osed -

technical specification changes meet the above criteria. The larger F z) allowances will be included in the COLR as a replacement for the curre.t n

' technical specification value of 2 percent.

Revisions to the COLR will'be evaluated in accordance with 10 CFR 50.59. COLR revisions.will assure conformance to 10 CFR 50.36.-

The NRC will be notified of all revisions to the COLR in'accordance with TS 6.9.1.6.

All COLR revisions will be based on NRC-approved methodologies. Revisions to the Fo(z) penalty will be based on the Westinghouse. methodology, previously reviewed and approved by the NRC, in WCAP-10216-P-A, Revision IA. Calculating 'this cycle-specific parameter in accordance with an approved NRC methodology ensures that the parameters are consistent with the. applicable safety analysis addressed in the CPSES final-t safety analysis report (FSAR) update.

. Therefore, the staff finds the proposed changes acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Texas State official was notified of the proposed issuance of the amendments.

The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

5 The amendments 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 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 amendments involve no significant hazards t

consideration, and there has been no public comment on such finding (59 FR 63127). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). This amendment also involves changes in record-keeping, reporting or administrative procedures or requirements. Accordingly, with respect to these items, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 551.22(c)(10).

Pursuant to 10 CFR 51.22(b), no environmental impact statement or invironmental assessment need be prepared in connection with the issuance of this amendment.

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6.0 CONCLUSION

t The Commission has concluded, based on the considerations discussed above,

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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 amendments will not be inimical to the common defense and security or to the health and safety of the public.

l Principal Contributor: Timothy J. Polich Date: March 1, 1995 i

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