ML20050D512

LER 82-021/03L-0:on 820302,during Normal Operation Surveillance Testing on Standby Gas Treatment Sys Charcoal Deluge Sys,A Train Found to Be Wet.Caused by Leaking Deluge Valve CV-5837 & Plugged Orifice in Drainline

ML20050D512
Person / Time
Site:	Duane Arnold
Issue date:	04/01/1982
From:	Varner D IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20050D509	List: ML20050D508 ML20050D512
References
LER-82-021-03L, LER-82-21-3L, NUDOCS 8204120272
Download: ML20050D512 (2)

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al OIQAfilg RI ?l@ 40 EVENT DESCRIPTION AND PRC8 A8LE CCNSECUENCES h l o 12 l l During normal operation while performino survnillanco toctinn nn thn eta I t o t a l I ndby gas treatment (SBGT) system charcoal bed deluce system, the "A" SRG I lo I AI I T system charcoal bed was found to be wet. As required by Technical Knor I Io is1 [ ification 3.7.B.3, a 7-day limiting condition for operation (tr0) was on f

[TTTI l tered. The redundant train of the RPGT svstnm was nnorahin. Tho 7-dav L,C 1 lol71 1 0 ended after 5.8 days when the "A" SRGT svstom uae man n na ra hi n _ Thorn I lo is j l have been no previous similar occurrences. I F 8 9 80 Sc$a" 'c'e'c'e' su'scEs ecuacNaNr cocs s sYe's sSc"$a lo191 iSlC l@ W@ l B l@ l Vf2 I Al L l Vl E! XI@ l El@ [D_J @

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CAusE oEsCaier.CN AND CCAAECTIVE ACTICNS h j i j o l l Water in the "A" SBGT charcoal bed was causod hv leakino deloce valve CV i li t i i 1 -5837A and plugged orifice in the deluge drain line. Contrihotino cause I i,,,,l is the desiqn of drain line pipina. CV-5837A was reworked and orifice el l l,63; l eared. Charcoal in "A" SBGT charcoal bed was replaced. "A" SBGT was test I ii t. i I ed sat. and made operable. Drain line pininn desian review plannod. I

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DUANE ARNOLD ENERGY CENTER

,.- Iowa Electric Light, and Power Company Licensee Event Report - Supplemental Data Docket No. 050-0331 Licensee Event Report Date: 4-1-82 Reportable Occurrence No.: 82-021 Event

Description:

During normal operation while performing surveillance testing on the standby gas treatment (SBGT) system charcoal bed deluge system, the "A" SBGT system charcoal bed was found to be wet. As required by Technical Specif' ation 3.7.B.3, a 7-day limiting condition for operation (LCO) was entered.' During *.he surveillance test, the level of charcoal in the "A" SBGT charcoal bed was found to be above the level of the deluge nozzles. When the excess charcoal was removed to inspect the deluge nozzles, it was discovered that the charcoal bed was wet. -

The redundant train of the SBGT system was operable. The 7-day LCO was ended after 5.8 days when the "A" SBGT system was made operable. There have been no previous similar occurrences.

Cause

Description:

The water in the "A" SBGT system charcoal bed was caused by leaking charcoal bed deluge valve CV-5837A. In addition, the orifice in the deluge drain line downstream of the leaking valve was plugged which prevented the' yalve leakage from draining. A contributing cause of the wet charcoal bed is the design of the deluge system piping. Because the deluge drain line is located at the same elevation as the deluge nozzle header, leakage from the deluge valve would not be drained before reaching the deluge nozzle elevation.

Corrective Action: .

Deluge valve CV-5837A was reworked to correct the leakage and the orifice in the deluge drain line was cleared. The charcoal in the "A" SBGT system charcoal bed was replaced. After these repairs, the "A" SBGT system was functionally tested satisfactorily and made operable. To preclude recurrence, a design review will be performed to consider changes to the deluge piping to both trains of the SBGT system charcoal beds. Potential changes include rerouting the deluge drain line to a low point in the piping downstream of the deluge valve and enlarging the orifice diameter in the deluge drain line.

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