ML20196C430

Safety Evaluation Supporting Amend 102 to License DPR-36

ML20196C430
Person / Time
Site:	Maine Yankee
Issue date:	02/09/1988
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20196C390	List: ML20196C385 ML20196C421 ML20196C430
References
NUDOCS 8802160097
Download: ML20196C430 (3)

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1. • o,, UNITED STATES

! o NUCLEAR REGULATORY COMMISSION 3 E WASHING TON, D. C. 20655

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SAFETY EVALUATION BY THJ OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO AMENDMENT N0.10' TO FACILITY OPERATING LICENSE N0. DPR-j MAINE YANKEE ATOMIC POWER COMPANY

, MAINE YANKEE ATOMIC POWER STATION DOCKET N0. 50-309 INTRODUCTION By letter dated July 30, 1987, Maine Yankee Atomic Power Company (the licensee) made application to revise the technical soecifications of the Mair.e Yankee Atomic Power Plant. The proposed revision would alter the actions required when the Incore Monitoring System becomes inoperable. The NRC staff has reviewed the licensee's application and prepared the following evaluation.

Maine Yankee currently uses the Incore Monitoring System to monitor the Linear Heat Generation Rate (LHGR) and determine the margin to the value of LHGR permitted by the LOCA analysis. If the incore alarms become inoperable power operation may continue if certain conditions are met. These include:

CEAs are maintained above the 100% power insertion limit Excore symmetric offset remains with +0.05 of the value measured when the last incore readings were taken Core power is reduced to less than or equal to P (% of rated power) when l P is given by: 1 P = 0.85 R, and R is the minimum value of the ratio (LOCA LHGR Limit / Latest Measured value of LHGR corrected to 100%

power)

The penalty factor of 0.85 accounts for the maximum possible loss in margin l that could result from operation within the restricted CEA and symetric offset limits. The flyspeck analysis used in the determination of the RPS setpoints forms the basis of this penalty, which is evaluated each cycle.

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-2 The proposed specification separates this combined penalty factor into CEA and symmetric offset components and expresses the penalty as a function of CEA movement relative to the CEA position at the time when the last incore readings were taken. In addition, the proposed specification defines two symmetric offset ranges to cover the most likely conditions of core operations.

The specific form that the proposed formula for the value of the reduced power is-P = [R-0.5S][LHR (limit)/LHR(measured)], where P = percent of rated power R = 85 for symmetric offset between 0.00 and +0.10 or

= 92 for symmetric offset between 0.00 and . 0.10, S = Number of steps, the CEAs deviate from the CEA position existing when the lirear heat rate measurement was taken, LHP (limit) = Linear heat rate permitted by LOCA analyses, and LHR /maasured) = Lirear heat rate last measured corrected to 100 percent power.

As before, the CEAs must be maintained above the full power insertion limits and the use of the algorithm is limited to fourteen full power days.

The same flyspeck peaking factor analysis that was used to arrive at the current penalty factor was used to construct the proposed algorithm. This analysis is a parametric study of the effect of CEA motion and symmetric offset on the peaking factor and is performed for each cycle. The l suitability of the proposed penalty factors will be evaluated for each '

cycle.

The current specification LOCA LHGR limits were determined using an approved I ECCS evaluation model and meet the criteria in 10 CFR 50.46 and 10 CRR Part 50 Appendix K. The proposed specification is based upon the same parametric analysis as the current specification and provides equal assurance that the LOCA LHGR limits will not be violated during operation when the Incore Monitoring l System is inoperable. We, therefore, find that the proposed revision to Technical l Specification 3.10C.3.1.1 is acceptable. l l

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0 ENVIRONMENTAL CONSIDERATION This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 70.

The staff has determined that the amendment involves no sianificant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no sianificant increase in individual or cumulative occupational radiation exposure. The Commission 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 set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statenent or environmental assessment need be prepared in connection with the issuance of this amendment.

CONCLUSI0d We have 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, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance '

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

Date: February 9, 1988 Principal Contributor: W. Brooks 1