ML19207A848

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Requests Addl Info for Degraded Grid Voltage
ML19207A848
Person / Time
Site: Maine Yankee
Issue date: 07/20/1979
From: Lainas G
Office of Nuclear Reactor Regulation
To: Reid R
Office of Nuclear Reactor Regulation
References
NUDOCS 7908220489
Download: ML19207A848 (3)


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UNITED STATES

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JUL 3 61979 MEMORANDUM FOR:

R. Reid, Chief, Operating Reactors Branch #4, Division of Operating Reactors FROM:

G. Lainas, Chief, Plant Systems Branch, Division of Operating Reartors

SUBJECT:

MAINE YANKEE, REQUEST FOR ADDITIONAL INFORMATION FOR DEGR?.DED GRID VOLTAGE (TAC 10032)

Plant Name: Maine Yankee Docket No.:

50-309 Responsible Branch ORB #4 Project Manager:

E. Conner Reviewing Branch:

Plant Systems Branch Status: Awaiting Information In response to technical assistance request TAC 10032, the Plant Systems Branch has reviewed the licensee's submittal of July 18, 1977 and found that additional infonnation is required in order to complete our review.

The attached request for additional information should be forwarded to the licensee as soon as possible with a request for response within 45 days.

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G. Lainas, Chief Plant Systems Branch Division of Operating Reactors

Contact:

S. Rhow, X28077 C. Cleveland, EG&G

Enclosure:

As stated

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D. Eisenhut W. Gammill B. Grimes E. Conner G. Lainas D. Tondi M. Chiramal P. Shemanski S. Rhow C. Cleveland, EG&G 761130

A REQUEST FOR ADDITIONAL INFORMATION MAINE YANKEE DEGRADED GRID VOLTAGE (TAC 10032)

Based on our review of your submittal dated July 25, 1977, we have concluded that your basis for not proposing a design modification to your plant electrical power distribution system undervoltage protection is not acceptable.

Your basis being that compliance with our positions, sub-mitted to you by our letter dated June 3,1977, violates GDC-17.

We contend that without a modification your existing system may not meet the requirements of GDC-17, since GDC-17 requires that the safety functions of each of the offsite and onsite system (assuming the other system is not functioning) shall be to provide sufficient capacity and capability to assume that:

(a) specified acceptable fuel limits and the design conditions for tte reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences; and (b) the core is cooled and cor.tainment integrity and other vital functions are maintained during any of the postulated accidents.

The offsite power system is the common source which normally supplies power to the redundant safety related buses. Any transient or sustained degradation of this common source will be reflected into the safety related buses and could result in loss or damage to redundant safety loads.

In view of the above, we require that you provide your proposed design modification and changes in the Technical Specification based on the guidance contained in the staff positions submitted to you by our letter dated June 3,1977.

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