ML19259C279

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Responds to IE Bulletin 79-01 Re Environ Qualification of Class IE Equipment.Solenoid on safety-related Valve in Unit 2 Containment Not Qualified.Solenoid Will Be Replaced Before Cycle 3 Operation
ML19259C279
Person / Time
Site: Millstone Dominion icon.png
Issue date: 04/18/1979
From: Counsil W
NORTHEAST UTILITIES
To: Reid R
Office of Nuclear Reactor Regulation
References
NUDOCS 7906140528
Download: ML19259C279 (2)


Text

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April 18, 1979 Docket No. 50-336 Director of Nuclear Reactor Regulation Attn: Mr. R. Reid, Chief Operating Reactors Branch #4 U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Reference:

(1) B. H. Grier letter to W. G. Counsil dated February '8,1979, forwarding I&E. Bulletin 79-01.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 I&E Bulletin 79-01 Environmental Oualification of Class lE Equipment In accordance with the reporting requirements of Reference (1), Northeast Nuclear Energy Company (NNECO) is advising the NRC Staff that it has been determined that one solenoid installed on a safety-related valve in the Millstone Unit No. 2 con-tainment has not been qualified for service in the LOCA envirorurent.

.The original design function of this valve, (2-CH-517), the auxiliary spray valve, is to cool the pressurizer when the pressure of the reactor coolant system is below that required to operate the reactor coolant pumps. This feature is described in FSAR Section 9.2.3.3. Since that time, a flow path utilizing this valve was established for the hot leg injection method of precluding postulated boron precipi-tation concerns following a LOCA. The fact that this valve is now being used for an additional application, beyond the original design intent, supports NNECO's conclusion that this lack of qualification is a unique situation.

The solenoid installed on 2-CH-517, Model Number 8302C27RF, Serial Number 22516A, will be replaced with an environmentally qualified solenoid prior to the start of Cycle 3 operation.

Although not reportable by the requirements of Ref erence (1), four other solenoids installed on safety-related valves within the Millstone Unit No. 2 containment are noted. These solenoids are fully qualified to perform their design function in a LOCA environment, unless subjected to a coincident undervoltage condition, i.e. ,90-100 V DC, applied to a solenoid with a nominal voltage rating of 125 V DC. The nonical DC voltage level within the plant is 130 - 132 volts, and it is not a credible, hypothesis to superimpose the requirements of a LOCA and a severe (less than 100 V) undervoltage condition on these solenolds. Therefore, the current solenoids are acceptable. However, it is the intention of NNECO to replace these four solenoids as soon as replacements are available, and during the current refueling outage, if possible. I f replacements cannot be procured on a schedule compatible with the start of Cycle 3 operation, replacement will be accomplished at the first suitable opportunity. I list of the specific valves, and the associated codel number and serial nu=ber, is provided as follows:

7906] q QS 2279 235 1

Valve Solenoid Model No. Serial No.

CH-518 HTX-8320A90V 77965A CH-519 HTX-8320A90V 77965A EB-91 HT-834445V 19820B EB-100 ET-834445V 19820B Because the information presented above is considered complete, the 14-day report requested in Reference (1) is not planned in this instance. Also, justification for continued operation is not applicable.

We trust the above infor=ation is respons_ve to your requests of Reference (1).

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

/ , /

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W. G. Counsil Vice President e

2279 236

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