ML20211L395

Safety Evaluation Supporting Amend 103 to License DPR-3 Re Max Nominal Enrichment of Fuel

ML20211L395
Person / Time
Site:	Yankee Rowe
Issue date:	02/17/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20211L342	List: ML20211L339 ML20211L356 ML20211L395
References
NUDOCS 8702270119
Download: ML20211L395 (4)

Text

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.103 TO FACILITY OPERATING LICENSE NO. DPR-3 YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION DOCKET NO.50-029

1.0 INTRODUCTION

By letter dated October 20, 1986, the Yankee Atomic Electric Company (YAEC) submitted a request for changes to the Yankee Nuclear Power Station Technical Specifications (TS). This letter superseded a June 24, 1986 application. Staff action on some of the changes in this application is deferred as discussed in YAEC's letter of December 18, 1986.

The amendment revises the allowable enrichment for reload fuel from a nominal 3.7 weight percent to a maximum nominal 4.0 weight percent U-235.

2.0 DISCUSSION Technical Specification 5.3.1 provides information on design features of the fuel assemblies. The existing specification states that reload fuel shall have a nominal enrichment of 3.7 weight percent U-235. This value has been appropriate for reload fuel used in the last few cycles. In earlier cycles, enrichments of 4.0 weight percent U-235 or more have been approved by the NRC, most recently in Cycle XIV.

As the TS specified that " reload fuel has a nominal enrichment of,"

the actual value for the fuel cycle was inserted as fuel characteristics changed. This enrichment has changed from 4.94 to 4.0 to 3.5 to 3.7 over the last several cycles of the plant. For future cycles, the licensee wishes to use reload fuel with up to 4.0 weight percent U-235; tjerefore, a Technical Specification change to set a maximum nominal enrichment of 4.0 weight percent U-235 was proposed.

3.0 EVALUATION The fuel enrichment is not a direct input to the reactor safety analysis. Fuel enrichment is used in conjunction with a nurrber of parameters and considerations in determining safe operation of the Q22{g 73$ 9 P

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reactor core. The fuel enrichment, number of fuel assemblies, exposure (burnup) of existing fuel, burnable poisons and fuel management schemes are used to derive measurable reactor core parameters important to safe operation. These dynamic parameters, such as rod worths and peaking factors, are currently included in the plant's TSs. The limits.on these parameters will'not be changed by the proposed amendment. .The specification of fuel enrichment in the core design section alone does not uniquely determine nor limit the values of the reactor core parameters which are important for safe operation. The existing safety limits and limiting conditions of operation in the TSs have to be addressed and evaluated for each specific' reload to take into account the fuel enrichment.

For a given cycle, safety and operating limits are verified acceptable to the appropriate criteria using analysis methodology previously reviewed and approved by the NRC. The safety analysis is performed assuming certain plant characteristics and protective features which are governed by the TS. Specifically, TS limiting conditions for operation and surveillance requirements.have been established for control rod insertion limits, peaking factors, reactor coolant system pressure and temperature and for instrumentation that provides automatic protective actions.

These requirements provide assurance that the plant is operated such that cladding and RCS integrity limits are maintained. If these TS limits can be met with the reload fuel, then applicable fuel design limits and other acceptance criteria will be satisfied. If operation with the reload fuel would result in parameters falling outside of these TS limits, NRC review and approval of the revised TS values would be required.

Therefore, since' enrichments as high as that proposed have been previously found acceptable at Yankee and since the effect of the actual enrichment is evaluated as discussed above, the staff finds this proposed TS change acceptable.

4.0 ENVIRONMENTAL CONSIDERATION

This amendment involves a change to a requirement with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any affluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion setforthin10CFR51.22(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 this amendment.

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5.0 CONCLUSION

The staff 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, ano(2)suchactivitieswillbeconductedincompliancewiththe Comission's regulations and the issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public.

6.0 ACKNOWLEDGEMENT Principal Contributors: M. Dunenfeld and E. McKenna Dated: February 17, 1987 i si

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