ML20137R816

Safety Evaluation Supporting Amend 171 to License DPR-35

ML20137R816
Person / Time
Site:	Pilgrim
Issue date:	04/07/1997
From:	NRC (Affiliation Not Assigned)
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ML20137R810	List: ML20137R816
References
NUDOCS 9704140257
Download: ML20137R816 (3)

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UNITED STATES b

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j NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. - mi s.,.....j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 1

RELATED TO AMENDMENT NO. 171 TO FAC.LITY OPERATING LICENSE NO. DPR-35 BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION l

DOCKET NO. 50-293 e

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1.0 INTRODUCTION

By letter dated January 24, 1997, as supplemented March 27, 1997, the Boston

-Edison Company (BEco) (the licensee) submitted a request for changes to the Pilgrim Nuclear Power Station (PNPS) Technical Specifications (TSs). The requested changes would revise (1) the Safety Limit Minimum Critical Power Ratio (SLMCPR) based on the cycle-specific analysis of the mixed core of Gell /GE10/GE88 fuel parameters and (2) an increate in the minimum critical power ratio (MCPR) criteria that define a limiting control rod pattern required by an increase in the SLMCPR. The March 27, 1997, letter provided i

clarifying information that did not change the initial proposed no significant s zards consideration determination.

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2.0 EVALUATION 4

The licensee requested a change to the PNPS Cycle 12 TSs in accordance with the 10 CFR 50.90. The proposed revision of the TS 2.1.2 and its associated Bases Sections 2.1, 2.1.1, 2.1.2, and Note 5 to TS Table 3.2.C.1 is described belou.

i (1) TS 2.I.2 and ASSOCIATED BASES SECTIONS The safety limit MCPR in TS 2.1.2 is proposed to change from 1.07 to 1.08 i

4 with the reactor steam dome pressure 1725 psig and core flow 110% of rated flow based on the cycle-specific analysis performed by GE for PNPS Cycle 12 mixed core of Gell /GE10/GE8B fuel. The cycle-specific parameters were used including the actual core loading, actual bundle parameters evaluated at the projected exposure distribution based on projected control blade patterns for the odded burn through the cycle, and the full cycle exposure range to determine the most limiting ~

point (s).

The staff has reviewed the proposed TS change which is based on the analyses performed using PNPS Cycle 12 cycle-specific inputs and approved j

methodologies including GESTAR II (NEDE-24Dll-P-A-ll Sections 1.1.5 and l.2.5) and NED0-10985-A, January 1977. Because the R-factor methodology referenced in NEDE-240ll-P-A-Il is not applicable to the part length i

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i Gell, an improved R-factor methodology described in NEDC-32505P, "

'R-Factor Calculation Method for Gell, GE12 and GE13 Fuel", November 1995 was used. The revised R-factor-calculation method uses the same NRC i

approved equation stated in GESTAR (NEDE-24011-P-A) with the. correction

-factors to account for the peaking factor effects due to.the part-length-L-

rod design..The staff has reviewed _'the'R-factor calculation method for J

the Gell, the relevant information.provided in the proposed Amendment 25 3

to GESTAR II, NEDE-24011 (which is under the' staff review) and the supplemental information dated March 26, 1997 in response to the staff E

request for additional information during a telephone conference on

. March 13, 1997. The staff has' found that the justification for analyzing.

and determining.the SLMCPR of 1.08 is acceptable for application to the Gell fuel in.PNPS Cycle 12 since Pilgrim Cycle 12 bundle has a flatter distribution of uncontrolled R-factors for the highest power rods in each bundle.

The licensee has revised the associated Bases sections related to the above TS changes for the SLMCPR. The proposed changes modify the Bases section to describe the methodology used in the calculation of the SLMCPR. The new Bases sections have been changed to reflect the i

new requirements and are consistent with the proposed amendment.

The new Bases pages 2.1, 2.2, 2.3, and 2.4 are included with the new TS pages. These changes are acceptable.

(2) Note 5 of Table 3.2.C.1 The staff discussed with the licensee by telecon the propo:ed SLMCPR change and corresponding changes to MCPR criteria in 1S section 3.2.C.I.

TS section 3.2.C.1 defines a limiting rod pattern criteria as MCPR < 1.40 for Core Thermal Power greater than 90% and MCPR < 1.70 for Core Thermal Power less than or equal to 90%.

These criteria were determined in the i

ARTS program analysis for Pilgrim. The SLMCPR assumed in this analysis is 1.07. An increase in the SLMCPR will require an increase in the MCPR j

criteria used to define a limiting rod pattern.

For a SLMCPR of 1.08, the MCPR criteria for a limiting rod pattern are MCPR < l.41 for Core Thermal Power greater than 90% and MCPR < l.72 for Core Thermal Power i

less than or equal to 90%. The rod withdrawal error analysis for Pilgrim i

Station is presented in the " ARTS Improvement Program Analysis for Pilgrim Nuclear Power Station," NEDC-31312-P, September 1987.

1 Applicability of this analysis for more recent fuel designs is verified as part of the reload core design analysis and is documented in the cycle-specific su)plemental reload licensing report.

Therefore, this change is accepta)1e to the staff, i-The licensee also stated that the linear heat generation rate (LHGR) limit has been reviewed for Cycle 12 for the rod withdrawal error, and that the current operability statement for the rod block monitor utilizing the revised criteria for a limiting rod pattern will provide adequate protection against exceeding the LHGR thermal limit, as well as SLMCPR, during a rod withdrawal error event. The licensee will continue to review the LHGR limit in future cycles. Based on NRC staff review, we i

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3-conclude that the changes to the TS for Pilgrim Cycle 12 application are analyzed based on the NRC-approved method.

The staff reviewed the request by BEco to revise the TS of the PNPS.and based on the review, conclude that these revisions are acceptable.

3.0 STATE _C0KSULTATION In accordance with the Commission's regulations, the Massachusetts 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. 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 i

exposure. The Comission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 6568). 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 environmenta1' 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 3

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 Contributors:

T. Huang G. Golub Date: April 7, 1997 1

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