ML20071F928

/03L-0 on 781101:auxiliary Feedwater Check Valve FW-164 Found to Be Oriented in Wrong Position.Caused by Missing Valve Disk Plate Which Was Subsequently Located & Recovered

ML20071F928
Person / Time
Site:	Fort Calhoun
Issue date:	11/27/1978
From:	Kusek L OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20071F926	List: ML20071F923 ML20071F928
References
LER-78-036-03L, LER-78-36-3L, NUDOCS 7812050179
Download: ML20071F928 (4)

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LICENSEE EVENT REPORT CONTROL BLOCK: l 1

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G Ti'l8 9l n i sLICENSEE i F i cCODE l e. l a 84 l@l IS 0 l o l 010 LICENSE l o l oNUMBER l 0 l o l 0 l n l 29o l@l 26 h 11 11 l111 l@L LICENSE TYPE JO I l@

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3 DOCKET NUMSER 69 75 EVENT DESCalPTION AND PROBABLE CONSEQUENCES h o#2l l Although no tilting dise check valves have been identified at the Fort Calhoun Stationt

. ; o ,3 ;  ; (Reference IE Circular 78-15), another type of' check valve which is orientation sensi-l io i4 l l tive was inspected during the 1978 refueling outage. As a result of the inspection, I l o p s ; l Auxiliary Feedwater check valve W-16k was found to be oriented in the wrong position.[

l 0 l6 l l Maintenance Order Number 20h29 was written to remove the valve and orient it correctlyJ l O [ 7 l l Upon disassembly of the valve, one of the two valve disk plates was missing. I a is 1 l l e, 30 SYSTEM CAUSE CAUSE COMP, VALVE CODE CODE SUSCODE COMPONENT CODE SutCODE SUBCODE l0l9]

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40 44 47 CAUSE DESCRIPTION AND CORRECTIVE Af"lONS l i l o l l W-16h is a Tyre 3"-C308, Style "B" Duo Chek, series 900 check valve. The hince lursl l i l i i l of the missing disk plate were broken at the clate. thus allovine the riste to carry I l7l lover to the steam generator during the cuarterly test of the auxiliary feedvater rumes.l i3 )3l l New valve internals for W-16h will be installed prior to sta' tuu. The missine plate l -

i li14) [vas located and recovered. l 7 e s 80 STA S  % POWER OTHER STATUS dis O RV DISCOVERY DESCRIPTION lilsllHl@ l0l0l0l@l NA l lDl@lIECircular78-15 l ACTIVITY CO T, NT REuASEo OpaEuASE LOCATiO~ O, REuASE @

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LE 78-036

.0maha'Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attachment No. 1 Safety Analysis The auxiliar/- feedvater system provides a redundant means of supplying the steam generators with feedvater. Operation of the system is automati-cally initiated on loss of power to the main steam generator feedvater pumps.

The system can also be manually operated. The purpose of check valve W-16h is to prevent the back-flow of water and steam from the steam generator to the auxiliary feedvater pumps and their associated discharge piping. With half of the disk plate missing from W-16k, the auxiliary feedvater piping between the steam generator and the auxiliary feedvater centainment isola-tion valves vould have been pressurized to steam generator pressure (approximately 780 psia at 100% power and 900 psia at zero power). The auxiliary feedvater piping in questic.n has a design pressure of 1600 psi and thus, no piping would have been overpressurized. In the event of failure of all three main feedvater pumps, the auxiliary feedvater pumps would have started to supply water to the steam generators. Steam genera-tor pressure vould have had to be overcome at the containment isolation valves rather than at W-164, but this fact would not have prevented proper operation of the auxiliary feedvater pumps.

Thus, in spite of the fact that half of the disk plate fror. W-16h was missing, the auxiliary feedvater system would still have been able to supply water to the steam generator in question, and the health and safety of the public would not be affected.

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IIR 78-036 0=aha Public Power District Fort Calhoun Station Unit No.1 Docket No. 05000285 Attachment No. 2 Corrective Action A complete set of new internals was obtained for W-16h and will be installed before startup from the refueling outage currently in progress. The valve disk

• plate material was changed from ASTM A216-WCB to kl6 Stainless Steel.

A search for the missing disk plate was conducted inside the steam genera-r tor. The plate was found on the tube sheet very near one of the handhole inspection ports.

The results of the steam generator secondary side visual inspection both before and after the missing disk plate was found, coupled with the results of stea= generator eddy current testing from both the present and 1977 refueling outages, indicate that no observable internal damage has occurred in the steam generator as a result of the loose disk plate.

The sister valve for the other steam generator (W-163) was disassembled and inspected. W-163 showed none of the damage evident in W-16h and it was reinstalled.

The inspection of si=ilar type valves for proper orientation is being scheduled.

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bR78-036 Omaha Public Power District .

Fort Calhoun Station Unit No.1 Docket No. 05000285 Attachment No. 3 Failure Data This is the first incident / failure of this type at the Fort Calhoun Statio .

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