ML20031F894

Responds to NUREG-0737 Item II.K.3.5,automatic Reactor Coolant Pump Trip.Requirement for Installation of Automatic Trip Sys Is Neither Warranted Nor Desirable

ML20031F894
Person / Time
Site:	Haddam Neck, Millstone  File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/14/1981
From:	Counsil W CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.05, TASK-TM A01379, A1379, TAC-49810, NUDOCS 8110200521
Download: ML20031F894 (2)

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Mr. Darrell G. Eisenhut, Director 00[] g 700/A

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U. S. Nuclear Regulatory Commission 7

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Reference:

(1)

D. G. Eisenhut letter to All Operating Pla'nts;hkdf Applicants for Operating Licenses and Holders of' Construction Permits, dated October 31, 1980, Forwarding NUREG-0737.

Gentlemen:

Haddam Neck Plant Millstone Nuclear Power Station Unit No. 2 NUREG-0737 Item II.K.3.5, Automatic Reactor Coolant Pump Trip Item II.K.3.5 of Reference (1) requires licensees to propose modifica-tions to automatically trip the reactor coolant p2aps during a Loss-of-Coolant Accident. In Reference (1) the Staff admits that " tripping of the reactor coolant pumps is not an ideal solution" but requires that "in the meantime, until a better solution is found, the reactor coolant p'2mps should be tripped automatically in case of a small-break IOCA."

Connecticut Yankee Atomic Power Company (CYAPCO), on behalf of the Haddam Neck Plant, and Northeast Nuclear Energy Company (NNECO), on behalf of Millstone Unit No. 2, have determined that the requirement for installation of an automatic trip system is neither warranted nor desirable at this time, and may in fact degrade plant safety during certain con-ditions. The loss of forced coolant flow during power operation is a potentially severe event. Failure of an automatic trip system which results in a reactor coolant pump trip would cause an unnecessary challenge to the Reactor Protection System as well as the entire plant as a trip from full power would result.

In addition, automatically tripping the Reactor Coolant Pumps during certain transients similar to a IOCA will g

lead to more severe consequences.

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Reactor operators at the Haddam Neck Plant and at Millstone Unit No. 2 are required to manually trip the reactor coolant pumps on receipt of a safety injection signal. Analyses have been performed and docketed to demonstrate that the existing plant design and procedures are adequate.

Operators are trained to recognize conditions when a reactor coolant pump trip is warranted (e.g. - high vibration) and to act accordingly, 8110200521 011014 DR ADOCK 05000213 PDR

. CYAPCO and IMECO have concluded that. an automatic Reactor Coolant Pump trip system is not required to ensure safe operation of the Haddam Neck Plant and Millstone Unit No. 2, and that such a system could potentially degrade plant safety. Plant procedures and operator training are adequate to ensure that the Reactor Coolant Pumps will be tripped when required if the operator determines they are not re-quired for a safe plant shutdown. CYAPCO and IMECO intend to reevaluate this position in light of new data if and when they become available.

We trust the Staff will find the above information sufficient to concur with our position and resolve the concerns of Action Plan Item II.K.3.5.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY CC 7ANY

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W.'G. Counsil Senior Vice President