05000324/LER-1981-020-03, /03L-0:on 810402,high Leakage Rate Past Valve Seat Found During Integrated Primary Containment Leak Rate Test on Chamber Vent Valves CAC-V22 & 2-CAC-V8.Caused by Misaligned Sealing Ring in Main V-8 Valve Body

/03L-0:on 810402,high Leakage Rate Past Valve Seat Found During Integrated Primary Containment Leak Rate Test on Chamber Vent Valves CAC-V22 & 2-CAC-V8.Caused by Misaligned Sealing Ring in Main V-8 Valve Body

ML20003H567
Person / Time
Site:	Brunswick
Issue date:	04/30/1981
From:	Pastva M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20003H564	List: 05000324/LER-1981-020, Forwards LER 81-020/03L-0 05000324/LER-1981-020-03, /03L-0:on 810402,high Leakage Rate Past Valve Seat Found During Integrated Primary Containment Leak Rate Test on Chamber Vent Valves CAC-V22 & 2-CAC-V8.Caused by Misaligned Sealing Ring in Main V-8 Valve Body
References
LER-81-020-03L, LER-81-20-3L, NUDOCS 8105060336
Download: ML20003H567 (2)

LER-1981-020, /03L-0:on 810402,high Leakage Rate Past Valve Seat Found During Integrated Primary Containment Leak Rate Test on Chamber Vent Valves CAC-V22 & 2-CAC-V8.Caused by Misaligned Sealing Ring in Main V-8 Valve Body

Event date:
Report date:
3241981020R03 - NRC Website

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@ l Following maintenance on suppression chamber vent valve, CAC-V22, Integrated Primary l

l Containment Leak Rate Test PT 20.5 was performed on this valve and the parallel valve ;

o 3 lTITl l 2-CAC-V8.

The measured combined leakaged rate for these valves where added to the l

l previously known primary containment leak rate produced a total leakage rate of l

o s [TTT1 (_>.60La for all primary containment penetration and valves.

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31 40 41 42 43 44 47 33 CAUSE OESCRIPTICN AND CORRECTIVE ACTIONS h l i l o l l Disassembly of both valves revealed a misaligned sealing ring in the main valve body l the valve seat. A new sealing ring and I 8 l of V-8 which caused a high leakage rate past g l retaining ring were installed in V-8 and both valves were reassembled and returned to ;

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o LER ATTACH.!ENT - RO # 2-81-20 Facility: BSEP Unit No. 2 Event Date: April 2,1981 4

This event occurred due to a misaligned valve disc sealing ring in the valve body of CACV8 which prevented the disc from properly sealing.

During the inspection of this valve, it was discovered that the heads of three of the eight l

adjacent 1/4 inch machine screws which fasten the valve retaining ring to the valve body had broken of f which prevented the retaining ring from uniformly holding the sealing ring in place. This apparently caused the sealing ring to become misa11gned when the valve was closed. The three broken retaining screws were removed from the valve body and were replaced with qualified replacements.

The sealing ring i.as also replaced to' ensure scaling uniformity and the valve was reassembled. A leak rate ' test of the valve determined it to be properly sealing and it was returned to service.

A review of the maintenance and operating history o,f this type valve did not reveal any similar event of broken screw heads in the' retaining ring assembly.

As there is no history of retaining screw failures in this valve or other valves - - - - - - -

of this type, this failu.;e is considered isolated and therefore requires no further action.

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