ML19269D123

LER 79-009/03L-0 on 790121:plant Chimney Sampling Sys Operating Incorrectly.Caused by Purge Valve V2 Being Stuck Open

ML19269D123
Person / Time
Site:	Dresden
Issue date:	02/20/1979
From:	Chan J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17173A634	List: ML17173A633 ML19269D123
References
LER-79-009-03L, LER-79-9-3L, NUDOCS 7902270352
Download: ML19269D123 (2)

Text

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• LICENSEE EVENT REFORT

. CCN90L BLOCK: l l l l l l l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATIONI 1 6 o 1 l I l L l D l R I S j 2 l@l 0 l 0*[- l 0 l0 l0 l0 l0 l- l0 l025lgl 264 l 1LICE'.SE l 1 l TYPE1 l1aJ @ 57 CAT l 58 lg 7 8 9 LICENSEE CCCE 14 15 uCENSE NLMBEa CCN'T ali RE CR 3g p lL 0 l 5 l 0 l 0 i 0 l 2 l 3 l7 gj 0 69 1 1l2l1j7)9 gj0l2l2l0 7l9l@

74 75 REPORT CATE s3 7 4 60 61 DCCAETr.UVBER 6d EVENT OATE EV2NT CESCRIPTICN AND PRO 3 ABLE CCNCECUENCES h o 2 i While Unit 2 was in steady state operation and Unit 3 was in cold shut down, it was  ;

f und that the planC chimney sampling system was operating incorrectly. Since the g o a l is g,, y steam jet air ejector conitors were operable the safety significance of this event  ;

g a s I minimal.

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80 7 0 9 SYSTEM CAUSE CAUSE CCYP VALVE CODE CODE SUBCODE COMPONENT COCE SUSCOOE SUSCOOE O si iM cl@ l Et@ I B i@ l vl Al LJ V! EI Xl@ l Dj @ l Dl @ 20 7 8 9 10 11 12, 13 18 13 SE QUE NTI AL OCCURRENCE REPORT REVISION EVENT YEAR REPCRT No. COCE TYPE N O.

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s3 35 .,6 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIC.'.S 'h It was found that the purge valve V2 was stuck open, thus continuously drawing air a l in-3 , i l from the turbine building into the system. The replaced valve was inadvertently ,

stalled backwards, still allowing building air to be drawn in. Following repair ,

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system flow still low due to plugged filter. Installation of condensate drain to

,, 3 eliminate moisture saturation of filters is under investigation. ,

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%PCWER oTH ER STATUS DisrOVE RY OISCOVERY OESCRIPTION s+

STATUS Found during activity samp .ng i s W@ l 0l 7 l 6 l@l U3 Shutdown l l B lg  ;

' ACTIVITY CO TENT pf LE ASED OF RELEASE AMOUNT OF ACTIVITY LOCATION CF RELEASE NA i e i Zi @ l zi@l NA l l' l 7 8 9 to 11 44 45 30 PER;ONNEL EMPCSUAES N U MP ~ ~4 TYPE D ESCR!PTICN 1 7 l0l0,0l@lzl@l N l PERSCNNE L iruuR ES NUv6E r4 DESCRIPTION 7

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NAME OF PREDARER - PHONE:

7902270352_

• s ATTAC M NT TO LICENSEE EVENT REPORT 79-09/03L-0 COM"GNWEALTH EDISON COMPAW (CNE)

DRESDEN UNIT -2 (ILDRS-2)

DOCKET # 050-237 While Unit 2 was in steady state operation and Unit 3 was in cold shutdown, it was determined the plant chimney sampling system was not operating correctly. Since the steam jet air ejector monitors

• were operable, the safety significance of this event was minimal.

On 1/21/79, a work request was initiated to investigate the problem.

It was found that the purge valva V2 was stuck open, allowing turbine building air to be continuously drawn into the system. The valve was replaced and the valve which was removed was disassembled. .It was found that the valve stem was bent. On 1/24/79, another investigation of a lo i flow problem revealed that the valve which had just been re-placed had been installed backwards, and once again was allowing air from the Turbine Building to be drawn into to system.

Despite the repair of the purge valve, a low flow problem persisted.

Further investigation showed that the particulate filter became plugged very frequently. Water stains could be found on the filters and the filter holder. Apparently the moisture of the warm air from the chimney condensed in the sampling pipe due to the extreme cold weather . It was found that in the original design of the system there was a loop drain. Apparently in a later modification, the drain was replaced by a heater. It is believed that this heater cannot handle the excessive condensation caused by the recent ex-cessively cold weather. An investigation is under way to determine if there is a need to reinstall the loop drain. Until the low flow problem is corrected, the filtet will be changed more frequently, to avoid moisture saturation.

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