ML20086D806

Updated AO 73-06:on 730302,chemist,while Attempting to Draw Offgas Sample,Discovered Improper Flow Through Offgas Sample/Monitoring Sys.Caused by Two Lines to Offgas Monitoring Sys Rolled During Mods

ML20086D806
Person / Time
Site:	Vermont Yankee
Issue date:	03/08/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086D809	List: ML20086D806 ML20086D814
References
AO-73-06, AO-73-6, VYV-2503, NUDOCS 8312050131
Download: ML20086D806 (2)

Text

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? ) VERMONT YANKMM NUCLEAR POWER CORPORATION SCVCtdTY GCVCtd OROVE GTRCET Rtrrl.AND, VF.Ith10NT 03701 ftEPLY To:

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U.S. ATOM 10 ENERGY

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[) Abnormal Occurrence No. A0-73-06

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Dear Sir:

(jf.i An defined by Technical Specifications for the Vernont Yankee Nuclear 1 i , Power Station, Section 6.7.B.d, we are reporting the following Abnornal t- Occurrence as A0-73-06, c) f -

At approximately 0800 on March 2 during a plant startup and power ascension, a chemist while attempting to draw an off-gas sample discovered g't.J; ~'

that there was improper flow through the off-gas sample /nonitoring systems.

ti7 This inoperability of the off-gas nonitoring system exceeds the Liniting Condition for Operation as defined by Section 3.8.A.1 of Technical Specifications. The subject section requires that at least one of f-gas monitoring sy, stem be operable at all times. The reactor was operating at 47% power at the time of this incident with a stack gas discharge rate of approximately 600 pCi/sec.

Investigation revealed that two lines going to the off-gas monitoring system had been rolled during systen modifications made during the last plant oatage. Since Technical Specification Sections 3.8.A.2 & .3 were not being exceeded no reduction of power was necessary. The system was repaired, checked out, and placed back in operation by 1000 on March 2.

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0 JKilt NUCL. CAR POWER COHPORATION Directorate of Licensing March 8, 1973 Page 2 The Plant Operatiens Revleu Committee concluded that the cause of the " roll" and subsequent failure of the retest to unearth it was due to the difficulty of detection where lines pass through a wall. Therefore, all instrument tubing nodifications should, in the future, be visually inspected for proper installation as was the practice in the past. Ir addition, if during this inspection the tubing passes through a wall such that visual verification is inpossible, a continuity check using fluids or other means must be perforned.

Very truly yours, VERlIONT YANKEE NUCLEAR POWER CORPORATION

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B.W. Rilev '

Plant Superintendent WPM /rph f

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