ML20138K432
| ML20138K432 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/12/1985 |
| From: | Charemagne Grimes Office of Nuclear Reactor Regulation |
| To: | Opeka J NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| NUDOCS 8512180435 | |
| Download: ML20138K432 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION
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December 12, 1985 Docket No.: 50-245 Mr. John F. Opeka, Senior Vice President Nuclear Engineering and Operations Northeast Nuclear Engineering Company Post Office Box 270 Hartford, Connecticut 06141-0270
Dear Mr. Opeka:
SUBJECT:
IMPLEMENTATION OF DEGRADED GRID PROTECTION FOR CLASS 1E POWER SYSTEMS Re: Millstone Nuclear Power Station, Unit No. 1 In a letter dated November 14, 1985, you proposed to delay implementation of plant modifications related to Degraded Grid Protection for Class 1E Power Systems from the current Reload No. 10 outage to Reload II currently scheduled for sumer 1987. Based on a recent study derived from the Probabilistic Safety Study (PSS) for Millstone 1, you concluded that the probability of a station blackout would increase by a factor of 2.4 if the previously approved modifications (NRC License Amendment No. 98 Letter dated June 14,1984) were completed. On this basis, you determined that final implementation of these modifications should not be made before the 1987 refueling outage, to allow sufficient time for any redesign and procurement of materials.
Although we will require additional information to confinn that the adverse impact of completing the degraded grid protection modifications outweighs the intended improvements, we agree that such a possibility is sufficient to justify a delay in completing the modifications to the ne.6.1 fueling outage. Therefore, we conclude that the proposed delay is accep" ile.
In the interim, the conditions found acceptable for cycle No.10 operation (Amendment 98) are applicable to cycle No.11 operation.
Inasmuch as our letter of July 31, 1985 identified this issue as being resolved independent of ISAP and you now propose to do additional design analyses we request that, within 30 days following your receipt of this letter, you provide a description of the probabilistic assessment results i
8512180435 e51212 DR ADOCK 0500 5
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4 Mr. John F. Opeka Millstone Nuclear Power Station Northeast Nuclear Energy Company Unit No. I cc:
Gerald Garfield, Esquire Kevin McCarthy, Director Day, Berry & Howard Radiation Control Unit Counselors at Law Department of Environmental City Place Protection Hartford, Connecticut 06103-3499 State Office Building Hartford, Connecticut 06106 Edward J. Mroczka Vice President, Nuclear Operations Northeast Utilities Service Company Post Office Box 270 Hartford, Connecticut 06141-0270 State of Connecticut Office of Policy and Management ATTN: Under Secretary Energy Division 80 Washington Street Hartford, Connecticut 06106 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Northeast Nuclear Energy Company ATTN: Superintendent Millstone Nuclear Power Station P. O. Box 128 Waterford, Connecticut 06385 Resident Inspector c/o U.S. NRC Millstone Nuclear Power Station P. O. Box 811 Niantic, Connecticut 06357 First Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385 i
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Decemb:r 12, 1985 e
Mr.-John F. Opeka I and ensuing design analysis, in a Supplement to ISAP Topic 1.25.
This request affects fewer than ten respondents and, therefore, an OMB clearance is not required in accordance with P. L.96-511.
J Sincerely, Original signed by:
C. I. Grimes Christopher I. Grimes, Director Integrated Safety Assessment Pro,1ect Directorate Division of PWR Licensing - 8 cc: See Next Page DISTRIBUTION y.g"N3 EJordan NSIC ISAPD Reading BGrimes PAnderson Local PDR JPartlow M80yle NRC PDR JShea FMiraglia CGrimes OELD ACRS (10) i J
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