ML20079N761

Safety Evaluation Supporting Amend 105 to License NPF-12

ML20079N761
Person / Time
Site:	Summer
Issue date:	10/22/1991
From:	Office of Nuclear Reactor Regulation
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ML20079N747	List: ML20079N746 ML20079N761
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NUDOCS 9111110383
Download: ML20079N761 (5)

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ENCLOSURE 1 a nsc u o

UNITED STATES

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'$9....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.105 TO FACILITY OPERATING LICENSE NO. NPF-12 SOUTH CAROLINA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1

. 3 D0CKET NO. 50-395

1.0 INTRODUCTION

By a letter dated November 16, 1990, South Carolina Electric & Gas Compar.y (SCE&G or the licensee) submitted a request for Technical Specifica'"n changes regarding a VANTAGE + fuel reload for the V. C. Sumer Nuclear Stan r., Unit 1 (Sumer Station), Cycle 7 core. The VANTAGE + fuel design is described in the Topical Report WCAP-12610, which was approved by the staff by letters dated July 1, and October 9 1991.

VANTAGE + fuel riesign involves a new cladding material called Zirlo. Although Zirlo's material properties are similar to Zircaloy-4 material propertiac, the staff has limited the approval of the VANTAGE + fuel applications for up to 60,000 mwd /MTU rod average burnup due to the lack of data beyond this range.

The Technical Specification changes involve the use of VANTAGE + fuel and Zirlo filler rods.

The Sumer Station Cycle 7 core will have about 50-60 percent VANTAGE 5 and 40-50 percent VANTAGE + fuel assemblies. The VANTAGE + fuel includes the following features:

Zirle clad fuel rods and guide thimbles, reconstitutable top nozz'.e, intermediate flow mixing grids, axial blankets, integral fuel burnable absorbers. The VANTAGE + core has been designed to have the same operating limits as the VANTAGE 5 core.

2.0 EVALUATION (1) Mechanical Decign As indicated earlier, the VANTAGE + fuel mechanical design is approved for licensing applications in the Topical Report WCAP-12610 up to a rod average burnup of 60,000 mwd /MTU. The VANTAGE + fuel is designed to be mechanically compatible with VANTAGE 5 fuel, i.e., VAMTAGE+ and VrNTAGE 5 are, for all practical purposes, mechanically identical except fcr different clad material.

Thus, from the fuel performance standpoint, the VANTAGE + fuel is 1

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essentially no offferent from the VANTAGE 5 fuel, and there are no mixed

. core-concerns for Cycle 7.

We therefore concludc that the VANTAGE + fuel is acceptable for the Sumer Station Cycle 7 reload from a mechanical design standpoint.

(2) Nuclear Design The two features in VANTAGE + fuel not present in taHTAGE 5 fuel that affect the nuclear design are:- (1) use of the Zirlo alloy for fuel rods and guide thimbles, and (2) use of annular axial blanket pellets. The VANTAGE + fuel has a-slight neutron;c difference from the VANTAGE 5 fuel nuclear design due to

the presence of niobium-in the Zirlo material, but this difference is insignificant. The use of annular axial blanket pellets is an optional design i

feature for Sumer Station, and the effect on neutronics is also very minimal.

We thus conclude that the VANTAGE + fuel nuclear design is acceptable for the Sumer Station Cycle 7 reload because the VAtlTAGE+ fuel nuclear design does not differ from the NRC-yproved _ VANTAGE 5 fuel nuclear design in any significant-manner.

-(3) Thermohydraulic Design

' The therreal and hydraulic analyses to support the VANTAGE

• fuel reload are-identical to the currently-approved analyses of VANTAGE 5 fuel since all pertinent parameters and characteristics are identical-to each other. He thus conclude th6t the VANTAGE + fuel thermohydraulic design is acceptable for.the Summer Station Cycle 7 reload.

(t) :Non-Loss-of-Coolant Accident (LOCA) Safety Analysis Based _ on the licensing basis accident analyses, the licensee determined that therv are only two non-LOCA accidents affected by the use of 71rlo material:

-(1) iccked rotor accident, and (?) a rod cluster control assembly (RCCA) ejection accident. According to the NRC-approved Topical Report WCAP-12610,-

the reanlysis showed that the use of the Zirlo alloy results in only a minor increase in the peak clad temperature compared to the' Zircaloy-4 clad peak 1temperatura.. Since the resultant peak clad temperature increase ~ is' minor-enough:to Lt considered-insignificant, ti,e staff has concluded that the results-of-approved tircaloy-4 clad analysis are applicable to the Zirlo clad for locked rotor ' accident. As for the RCCA ejection accident, the reanalysis showed that the use_of Zirlo allow results in a-small reduction in fuel n. citing-fraction and ftel-stored energy when compared to the Zircaloy-4 clad results which is not significant.

Thus the peak RCS pressure is unaffected by the tau of Zirlo alloy feel clad. Based on the NRC-appreved Topical Report WCAp-12610, therefore, we contlude that the licensee has ade.quately addressed the concern of_ non-LOCA accideat analysis including locked rotor and-RCCA ejection for the Summer 9tction Cych 7 reload.

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! (E) LOCA Safety Analysis The LOCA analysis was described in Appendices F and G of WCAP-12610.

These Appendices were approved by the NRC staf f in c Safety Ev01uation (SE) dated October 9, 1991.

The SE concluded that ecch licensee referenciro Topical Report WCAP-12610, Appendices F ard G, should apply for an exemption from the requirements of 10 CFR 50.46, and 50.44, to allow their application to Zirlo fuel.

In the case of Jummer Station, the Connission, on its cwn initative, has prepared such an exemption.

This exemption will be issued along with the proposed amendaent.

The Safety Evaluation also conr.luded that the use of Baker-Just correlation to calculate rcetal-water reaccion is ccnservative f or Zirlo material.

Thus, the SE found that the application of 10 CFR 50.44, 50.46 and Appendix K is appropriate for the Zirlo material and that the LOCA Safety Analvsis as described in Appendices F and G of WCAP-12610 shows that Zirlo clad fuel is acceptable for the Summer Station Cycle 7 ieload.

(6) Technical Specification Changes Section 5.3, Reactor Core, Fuel Assemblies Section, was revised to incorporate the Zirlo alloys in addition to Zircaloy-4. As discussed in the evaluation, we~

have approved Topical Report WCAP-12610, therefo-o, this change is acceptable.

4.0 SUkMARY We have reviewed the licensee submittal of VANTAGE + fuel design and Technical Specification changes for the Suncer Station Cycle 7 reload. Based on the NRC-approved Topical Report WCAP-12610 and the plant-specific analyses, we i

approve the use of VANTAGE + fuel design and Technical Specifichtion changes for L

Summer Station Cycle 7.

5.0 STATE CONSULTATION

In accordance with the Commission's regulations, the appropriate South Carolina State official was notified of the proposed issuance of the amendment.

The State official had no comments.

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6.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a i

facility component located within the restricted area as defined in 10 CFR l

Part 20. The NRC staff has determinea that the amendment involves no significant L

increase in the amounts, and no significant change in the types, of any E

effluents that may be rele: sed offsite, and that there is no signi'icent increase in individual or_ cumulative occupational radiation exposure.

The Conmission b5s previously issued a proposed finding that the amendment involves no signifir:n' 'azards consideration, and there has been no_ public comment on I

such finding (55 FR 53076 - December 26,1990). Accordingly, the amenoment caets the eligibility criteria for categorical exclusion set forth in-10 CFR l

51.z2(c)(9).

Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmeidal assessment need be prepared in cennection with the issuance of the anendnent.

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7.0 CONCLt!SION 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 comnon defense and security or to the health and safety of-the public.

Principal Contributor:

S. L. Fu Date: October 22, 1991 e

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AMENDMENT NO.

105 10 FACILITY 0PT. RATING LICENSE N0. NDF SUMMER, UNIT No. 1 Docket File NRC PDR Local PDR PD11-1 Reading)

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