ML20086D823

Telecopy Ro:On 760504,during Routine Surveillance Test, Primary Containment Oxygen Concentration Found to Be in Excess of Tech Spec Limit.Caused by Leakage from Drywell Instrument Air Sys Into Containment Nitrogen Supply Line

ML20086D823
Person / Time
Site:	Monticello, 05000000
Issue date:	05/05/1976
From:	Larson C NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19289B550	List: 05000000/LER-1977-012, :on 770620,during Investigation of Cycle 5 Max Critical Power Ratio Limits,Ge Found That Pump Trip Delay Time Assumed in Original Cycle 5 Transient Analysis Not Appropriate.Amend Request Will Be Submitted 05000000/LER-1977-020-03, /03L:on 770404,RCS Leakage Determined to Be Greater than 10 Gpm.Caused by Packing Leakage Past Stems on RTD Bypass Throttle Valves 13RC20 & 14RC20.Valves Placed on Backseat & Stem Leakage Decreased 05000000/LER-1977-038-03, /03L:on 770519,RCS Leakage Determined to Be Greater than 10 Gpm from Stem Leakoff on Manual Isolation Valves 1PS24 & 1PS28 for Pressurizer Spray Valves.Caused by Packing Leakage.Valves Will Be Repacked at Next Outage ML20086D481 ML20086D514 ML20086D520 ML20086D537 ML20086D550 ML20086D554 ML20086D557 ML20086D561 ML20086D567 ML20086D606 ML20086D642 ML20086D691 ML20086D703 ML20086D760 ML20086D788 ML20086D818 ML20086D823
References
NUDOCS 8312050159
Download: ML20086D823 (2)

Text

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Wo m T.H.E R-N-S.T A.7 E S.

P-O W"It R C.O. rey ANT r

Monticello. Nuclear Genemeing P.lant Mant3 cello, Mirulesota 55362 r

May 5, 1976 Mr. J. G. Keppler, Director Region 113 Office of Inspect $on and Faforcement United States Ibclear Regulatory Comission 799 Rooseve).t Road Glen lulyn, Illinois 60137 Dear Mr. Koppler-I N0lfMC111b M1CLE4R GDURATIlfG PIANP Docket No. 50-263 Licenso No. DPR-22 On Wy 4,1976, during a routine surve.illance test, the primary contairiment oxygen concentratien was found to be in excess of the. 'h;:chnical. Specifications lirait of 5%. The oxygen concentration a s approximately 6.57..

The problea L-as caused try leakage from the drywell instrtet air systers into the. contain-ment nitrogen supply line via a solenoid valve.

h solenoid valvo as isolated and the primary corttainment. oxygen concentration us roduced to tw. low Tecimical Specification lireits.

Purther investigation of this occurrence is continuing.

Yours very t ly, C. E. La o.w Plantlunager CEL/kik cc: Director, Office of Nanagement Infonuation f Program Control (2. copies) t G Charanit Mitmesota Pollution. Cbutiv>l Agency Attn: J W Fenean File Copy sent try telecopier to Keppler.

8312050159 700426 DR ADOCK 05000263 PDR

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