ML20010E095

Forwards Safety Evaluation of SEP Topic VII-6, Frequency Decay. Facility Meets Current Licensing Criteria

ML20010E095
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	08/28/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Counsil W CONNECTICUT YANKEE ATOMIC POWER CO.
References
TASK-07-06, TASK-7-6, TASK-RR LSO5-81-08-068, LSO5-81-8-68, NUDOCS 8109030070
Download: ML20010E095 (4)

Text

O August 28, 1981 Docket i:o. 50-21; p\\ \\ 'm, i t D' /h f

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Dear t'r. Counsil:

SUCJECT:

SEP TOPIC '!II-6, FREQUEt:CY DECAY SAFETY EVALUATI0ti FOR HAD9A'1 liECK The enclosed staff saff evaluation is based on a contractor document that has been made available to you previously. This evaluaticn is the staff's position regarding design of your facility.in the subject area.

With ragard to the referenced topic, the staff has concluded that your facility meets current licensing criteria.

Sincerely, Dennis it. Crutchfield, Chief Operating P.eactors Branch flo. 5 Division of Licensing E.ic ksure:

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HADDAM NECK l

Docket No. 50-213

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Mr. W. G. Counsil t

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L ay, Berry & Itoward Counselors at Law l

One Constitution Plaza llartford, Connecticut 06103 4

Superintendcat Haddam Neck Plant 4

RFD #1 Post Office Box 127E East Hampton, Connecticut 05424 Mr. Richard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency 1

ATTN: Assistant Director Research and Policy Development 1

i Department of Planning and

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Energy Policy i

20 Grand Street l

Hartford, Connecticut 06106 U. S. Environmental Protection Agency Region 1 Office ATTN: EIS COORDINATOR JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station c/o U. S. NRC East Haddam Post Office East Haddam, Connecticut 06423 I

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SYSTEMATIC EVALUATI0fl PROGRAM

~-T0PIC VII-6 HADDAM tlECK TOPIC VII-6 FREQUEt;CY DECAY I.

Introduction Isse 9 of t;0 REG-0138 states that the staff.should require that a post-ulated rapid decay of the frequency of the offsite power system be included in the accident analysis and that the results be demonstrated to be acceptable. Alternatively, the reactor coolant pump (RCP) circuit breakers shculd be designed to protection system criteria and tripped to separate the pump motors from the offsite power system ber.ause iapid decay of the frequency of offsite power system has the pc'.e..tial for slowing down or braking the RCP thereby reducing the coolant flow rates to levels not considered in previous analyses.

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II.

Review Criteria The review criteria for reactor trip systems are presented in Table 7-1 of the Standard Review Plan.

III. Related Safety Tocics and Interfaces Set Points (Topic VII-1.A) and Degraded Grid (Topic VIII-1.A) are relat-ed review areas that are outside the scope of this Topic.

j Although Topic VIII-1. A is not dependent on the present topic for comp '

letion, the conclusions with regard to frequency decay should be compat-able.

IV. Review Guidelines Issue 9 of tiUREG-0138, " Staff Discussion of Fifteen Technical Issues Listed in Attachment to tiovember 3,1976 Memorandum from Director, fiRR to f1RR Staff," provides suitable guidance for this review.

V.

Evaluation Oak Ridge National Laboratory (ORtil), under a technical assistance program, reviewed the frequency decay rate phenomena and its effects on RCP's. The results of the review are presented in Section 4 of fiUREG CR 1464, " Review of tiuclear Power Plant Offsite Power Source Reliability and Related Recom-mended Changes to the !1RC Rules and Regulations." In sumary, the report shows that the conditicas required for dynamic braking of reactor coolant pumps are a sustained and ra M d decrease in frequency while maintaining bus voltage. These conditions are only reali:ed in a highly capacitive system using large amounts of buiied transmission cables (such as Long

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Island).

The Connecticut Yankee Atomic Power system does not use large amounts of buried transmission cable.

VI.

Conclusion l

l lhe conditions necessary for an unacceptable frequency decay rate are not present in the Haddam ficck offsite electrical distribution system.

Accordingly, the staff considers this issue not to be applicable to Haddam fieck.

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