ML20083D066
| ML20083D066 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/17/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20083D065 | List: |
| References | |
| TAC-M91372, NUDOCS 9505240161 | |
| Download: ML20083D066 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 20066 4001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.113 TO FACILITY OPERATING LICENSE NO. NPF-49
' NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 DOCKET NO. 50-423
1.0 INTRODUCTION
By letter dated January 18, 1995 the Northeast Nuclear Energy Company (the licensee) submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 3 Technical Specifications (TSs). The requested changes would revise the TSs to increase the minimum required boron concentration in the boric acid tank (BAT) from 6300 to 6600 ppm. The increase is required to meet the latest analysis for Cycle 6 which includes additional conservatisms which are meant to ensure the new required boron concentration will bound future cycle varutions.
2.0 EVALUATION The current Cycle 5 TS value for the minimum boron concentration in the BAT is 6300 ppm. This value was set by previous Westinghouse BORDER analyses. The BORDER evaluation determines the ability to maintain shutdown margin when the plant is taken from initial operating condition of Mode 1 or 2 to a final condition of mode 5 or 6 using an assumed minimum BAT concentration.
For Millstone 3 Cycle 6 the BORDER evaluation included the following j
conservatisms which attempt to ensure that future cycle variations and j
redesign effects are bounded:
1 1.
The best-estimate critical boron concentration for the Mode 1/2 initial condition was decreased by 50 ppm.
2.
The best-estimate maximum required Mode 5/6 boron concentration was increased by 50 ppm.
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Based on the results of this evaluation, it was determined that the minimum BAT borun concentration needed to meet shutdown margin requirements is 6600 ppm. The licensee believes that increasing the minimum BAT concentration to 6600 ppm at this time should ensure that shutdown margin requirements will be 9505240161 950517 PDR ADOCK 05000423 P
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o maintained for subsequent cycles. This will avoid additional increases if future operations and core loading are similar to that of Cycle 6.
t The licensee is proposing to increase the current BAT minimum concentration from 6300 ppa to a value of 6600 ppe. This implementation is achieved by changes to the following TSs.
Section 3.1.'1.1.1 Shutdown Margin - Modes 1 and 2 Section 3.1.1.1.2 Shutdown Margin - Modes 3,4, and 5 - Loops filled Section 3.1.1.2 Shutdown Margin - Cold Shutdown - Loops not Filled Section 3.1.2.5 Borated Water Source - Shutdown 4
i Section 3.1.2.6 Borated Water Sources - Operating Sectior. 3.9.1.1 Boron Concentration Section 3.10.1 Shutdown Margin Bases Section 3/4 1.2 Boration Systems Increasing the required minimum BAT concentration from 6300 ppa to 6600 ppe enhances plant safety. The methods used to calculate the cycle-specific boron limit have been previously reviewed by the staff and have been approved. The.
1 proposed changes to TSs for Millstone 3 are acceptable to the staff.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
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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 deftaed 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 exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (60 FR 8753). 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 environmental assessment need be prepared in connection with the issuance of the amendment.
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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 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 Contributor:
G. Schwenk Date:
May 17, 1995 l
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