ML20212G445
| ML20212G445 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/27/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20212G441 | List: |
| References | |
| NUDOCS 9711060181 | |
| Download: ML20212G445 (3) | |
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NUCLEAR REO.ULATORY COMMISSION WASHINGTON. D.C. m =1
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 209 4
TO FACILITY OPERATING LICENSE NO. DPR-65 i
NORTHEAST NUCLEAR ENERGY COMPANY THE CONNECTICUT LIGHT AND POWER COMPANY THE WESTERN MASSACHUSETTS ELECTRIC COMPANY HILLSTONE NUCLEAR POWER STATION. UNIT NO. 2 DOCKET NO. 50-336
1.0 INTRODUCTION
By letter dated September 2,1997, the Northeast Nuclear Energy Company, et al. (the licensee) submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 2, Technical Specifications changes would modify the TSs for the maximum allowed (TSs).The proposed primary containment internal pressure during normal operation.
Specifically, the proposed changes would modify TS 3.6.1.4, " Containment System Internal Pressure," from 2.1 pounds per square inch gauge (psig) to 1.0 psig. The TS Bases, Section 3/4.6.1.4, would also be modified to reflect the new maximum allowed internal primary containment pressure of 1.0 psig.
2.0 BACKGROUND
The licensee is in the process of reanalyzing the main steamline break accident for Millstone, Unit No. 2, and has determined that it is necessary to require a lower initial primary containment internal pressure as an initial condition in performing the analysis. This initial maximum primary containment internal pressure of 1.0 psig, combined with a proposed plant modification to add cavitating ventures in the auxiliary feedwater (AFW) discharge lines to each steam generator, should result in the reanalysis indicating that the peak primary containment internal pressure following a main steamline break will not exceed the design pressure of 54 psig.
The reanalysis of the main steamline break is required to be completed and approved prior to the restart of Millstone, Unit No. 2.
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. 3.0 EVALUATION i
The previous main steamline break analysis assumed that the AFW flow, at the initiation of an event, was the result of a single failure. However, the use of the AFW to supply the steam generators is normal, up to approximately 3 percent power, in accordance with the current operating procedures.
The i
ommission of not including the AFW flows was identified in Liceasee Event
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Report (LER) 97-006-00, dated February ll, 1997.
The licensee committed in the LER to implement corrective actions prior to restart from the current extended outage. The corrective actions necessary include the plant I
i modification and reanalysis, as previously discussed.
The reanalysis will determine the effect of various AFW flow rates to a steam generator, assuming a main steamline break inside containment, and the resulting primary containment peak pressure.
Using the existing TS maximum 3
primary containment initial ressure of 2.1 psig could provide results that could exceed the 54 psi design limit. As previously noted, reducing the maximum primary containment nitial pressure requirement in the TSs to 1.0 psig will result in a reduction of the peak primary containment pressure 4
resulting from a main steamline break inside of containment.
Therefore, to ensure that the lower initial primary containment maximum pressure is maintained, the NRC staff has determined that the proposed change to TS 3.6.1.4 from a maximum initial pressure of 2.1 )sig to 1.0 psig is 4
acceptable. The NRC staff has also determined that tie proposed update of the TS Bases, Section 3/4.6.1.4, to reflect the change in the primary containment ma timum initial pressure is also acceptable.
4.0 STATE CONSULTATION
f 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.
5.0 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 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 (62 FR 50007 dated September 24,1997).
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 er environmental assessment need be prepared in connection with the issuance of the amendment.
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6.0 CONCLUSION
The Comtssion has concluded bated 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 Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
D. Mcdonald Date:
October 27, 1997 G
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