ML20071F482

/03L-0 on 780908:Inadvertent Radioactive Gas Release to Atmosphere Caused by Leakage Past Check Valve CH-284,HG-100 & Relief Valve HG-105.Valves Will Be Inspected & Replaced or Repaired During Next Refueling Outage

ML20071F482
Person / Time
Site:	Fort Calhoun
Issue date:	10/06/1978
From:	Gates G OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20071F475	List: ML20071F472 ML20071F482
References
LER-78-029-03L, LER-78-29-3L, NUDOCS 7810110114
Download: ML20071F482 (4)

Text

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LICENSEE EVENT REPORT CONTROL SLCCK: l 1

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) lo l11

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TvPE ao CON'T lotil %RC I L }@l o j 51010 t o 12 i S 15 )@l 0 j 9101817 l 8 }@]l l 0 l016 !? l:80l@ 74 76 7 4 60 41 DOCK ET NUMBER 68 Sif EVENT DATE REPORT QATE EVENT DESCRIPTION AND PACS ABLF. CONSEQUENCES h lo I:l l Inadvertent radicactive gas release to the at:0 sphere Occu red due to les.kaze "re= thal ioi3l l che. ical volu=e control tank through check valvas CH-28h and E%100 and relief vai r. I l o t a l I E%105. Operatd ens noted e adual decrease in tank tressu*e and 4 '* * ** e4 e-*d -- '- l l0tsl l gag relief valve EG-105 and isolate E%105 vith valve E%101. Paleases were l I o i s 1 Mthin Te" ' ~' Stecification Limits.  !

l0l7l l l D4I I 80 7 8 9 SYSTE M CAUSE CAUSE COMP vALv; CCCE CDCE SUSCCCE COMPONENT CCDE SUSCCCE $UBCQQE 1o191 7 4 iPIC 9 to l@ [E_l@ L 3.J @ l vi Al il v t E l x i@ l x I@ La_J 11 12 13 18 1s 20

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AC*l C N PUvuRE EPPECT SMUTCOWN ATT AC MM E NT NPRO4 PRIME COMP. COMPONENT TA8C E N ACTION ON PVANT METaCQ MOURS SU8uiTTED PORMbuS SUP*LI E R uANUPACTURER

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33 J. 2S 3 e. 40 41 CAUSE DESCRIPTICN AND CCRRECTIVE ACTIONS l i 10 I I"he release was caused by leakare tast check - alve CH-29h . E3;100 and r. lief ral.r. I i- #ij !E% 105. Relief valve E % 105 was carred and isolatten r0-101 vae ~1~>-'-'- I

[ ] lthe release. *he check valves and relief valves vill ba insracted ard rarl"e-d -- J l j l l repaired durine the ner re.^2elin eutare. I Wl 7 8 9 90 P act Lin YETWOO CP STATUS  % POWER OTWER STATUS Ot $COV E R Y OISCQvtRv 0ESCRIPTf 0N -4 l !s i4 12 l@ l 01 o l Sl@l  ::A 44 l IAl@l 45 46 0:erater Obse-ratien _I 80 7 3 to 1 11 ACTivtTV CONTENT FELEASED 0FRELEASE AMOUNT OF ACTIVITY **

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NUM9ER OESCRiPTICN 41 l' ia $l 101010 l@l :iA I 9 11 1 30 LC13 OF OR DAuaGE TO PACIUTv TYPE OESCRIPTION l1 l9ll* l lIA l 7 8 9 10 3:

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LER 76-029 -

Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000235 Attachment No. 1 Analysis of Occur ence/Safetr Analysis During nor: sal steady state power operation the operators noticed a gradual decrease in chemical volume control tank pressure. Investigation by the opera-tors indicated that stack activity sonitored by P& O62 also.showed a slight increase whenever the tank was pressurized.

Maintenance Order No.19962 was issued to gag HG-105, the suspected leakage point. The required maintenance was completed on September 8, 197S.

Subsequent review of the stack activity readings indicated that the periodic release of gas due to pressurization of the volume control tank had occurred on each of 3 previous days.

The total amount of activity released has been esiculated to be 110.22 curies.

This li=1t is reported as a 30-day written report since the radioactive gas releases were due to an abnor: sal degradation other than fuel cladding, reactor ecolant pressure boundary or primary containment.

The ~ ^ - instantaneous release rate was 1260 pCi/see which is less than the Technical Specification limit to 33,000 #01/see release rate of gasecus activity excluding halegens and particulates with half lives greater than S days.

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d LEE 78-029 , , ,

Omaha Public Pcver District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attachment No. 2 Cor eetive Action

1. The relief valve HG-105 vill be inspected and repaired as necessary during the next refueling cutage.

2. The check valves CH-26h and HG-100 vill be inspected as necessary during the next refueling outage.

3. This event is the second failure occurrence of check valves CH-2Sh and HG-100. To prevent further reoccurrences, investigation is presently being conducted by the licensee to determine if another type of check valve would be more desirable in this system.

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. LER 78-029 Omaha Publie' Poser District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attachment No. 3 Failure Data This is the third event at Fort Calhoun which has resulted in a gas release due to valve leakby.

Refer to LIR 50-285/76-15 , ,

LIR 77-lh -

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