ML20086H300

Ao:On 720904,two Solenoid Operated Isolatation Valves in Torus Sampling Connection Found Not to Close on Isolation Signal.Caused by Valve Piston Binding.Piston Rings Removed, Valves Cleaned & Reassembled

ML20086H300
Person / Time
Site:	Vermont Yankee
Issue date:	09/29/1972
From:	Rosalyn Jones VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086H282	List: ML20086H288 ML20086H295 ML20086H300 ML20086H303 ML20086H307 ML20086H309
References
VYV-2256, NUDOCS 8401160335
Download: ML20086H300 (1)

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Q O VsuMorr Y ANI ME NUCLEAR POWER CORPORXrION " ~

MJ srvtr Tv SEVEN GROVE STREC#

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t,q", yy sta pty to- 3, P 0, nov 157 VFRNON VERMONT o*354 September 29. 1972

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Directorate of Liceasing #9 o /'

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United States Atem!c Enorgy Commission k'a n M ng t on , D. r'. !0 5 '+ 5  !)

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Reference:

Operating 1.icense DPR-28 \ . g.[.%, 4- p '/

Decket No. 50-171 \g ). */h '

Dear Sit :

In accordance with Technical Speci fications for the Vermont i'ankee Nuclear Power Station , Seutten 6. .t.a. we are reporting the following substantial vartance f rom pert ormance specifications given in Table 3.7.i.o.

1n the afternoon of September 4, while conducting a valve lineup and isolation valve operational check in the process of establishing Primary Con tainment , tbc two solenoid operated isolation valves in the torus sampling connection for the Containment Air Sampling System were found not to close on an isolation signal. After investigation

• of the valve internals and discussion with the vendor ( Atkomatic Valve Company), it was determined that dust, due to construction activities 1 had accumulated within the valve internals and had caused binding of the valve piston.

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The piston rines in the valve operator were removed upon vendor reconmendatien, to 3rovide greater clearance for the piston and, thus, reduce the resistance offered to solenoid operation. The valve bodies were cleaned, seatw were inspected and the valves were reassembled.

The valves were t!ien cycled repeatedly with satisf actory results and containment Nas est ablished. Due to the structure of the valve bodv, removal of the operating piston rings does not affect the integrity of '

primary containment. it should be pointed out that these valves are located within a closed loop and do not serve to iselate the primary centainment from secondary containment.

8401160335 721024 PDR ADOCK 05000271 Very truly yours, Q'S }

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Q,RMONT,YANI$EENUCLEARPOWE

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,*i- RobertF.ydnes

' Plant Superintendent' (19 m DWE/Ik *~

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