ML20076B087

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Notifies That stem-mounted Limit Switches on Valves SI-614, SI-624,SI-634 & SI-644 Will Not Be Replaced;Valves Do Not Perform safety-related Function
ML20076B087
Person / Time
Site: Millstone Dominion icon.png
Issue date: 05/08/1979
From: Counsil W, Switzer D
NORTHEAST UTILITIES
To: Reid R
Office of Nuclear Reactor Regulation
References
TAC-46174, NUDOCS 7905160262
Download: ML20076B087 (2)


Text

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NORTHI!AST IFFII.rFIIES

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P.O. BOX 270

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HARTFORo. CONNECTICUT 06101 v m., u i, u n.aw m A ""

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May 8, 1979 Docket No. 50-336

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Director of Nuclear Reactor Regulation o-Attn:

Mr. R. Reid, Chief

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Operating Reactors Branch #4 U. S. Nuclear Regulatory Commission

,q Washington, D. C.

20555 V

References:

(1)

W. G. Counsil letter to R. Reid dated March 23, 1979.

(2)

W. G. Counsil letter to R. Reid dated April 6,1979.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Environmental Qualification of Class lE Equipment In Reference (1), Northeast Nuclear Energy Company (NNECO) advised the NRC Staff that certain stem-mounted limit switches (SMLS) on safety-related valves in the Millstone Unit No. 2 containment may not be suitable for service in the LOCA environment. Reference (2) indicated that replacement of all SMLS's identified in Reference (1) would be completed prior to the start of Cycle 3 operation, unless modified by future correspondence.

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Please be advised that on Valves SI-614, SI-624, SI-634, and SI-644, the SMLS's will not be replaced. Further review has revealed that the SMLS's need not be environmentally qualified for post-LOCA conditions for the above four valves.

The control and indication functions are derived from a limit switch which is integral to the motor operator. This limit switch will continue to function post-LOCA. The only function that the SMLS's perform is for valve position annunciation which is not a safety-related function. Therefore, replacement is not necessary in these cases.

It is also noted that Valves Sl-651 and SI-652 were inadvertently included in the Reference (1) lut. These valves are not equipped with SMLS's and, therefore, should not h:ve been included.

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The remaining SMLS's identified in Reference (1) will be replaced with environmentally qualified switches prior to the start of Cycle 3 operation.

Very truly yours, NORTllEAST NUCLEAR ENERGY COMPANY f! bbw+w 4

W. G. Counsil Vice President l

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By:

f D. C. Switzer

'j President O

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