05000281/LER-1983-046-03, /03L-0:on 831004,valve MOV-R5-255A Became Inoperable When Valve Operator Support Broke Loose from Floor Mounting During Attempt to Cycle Valve.Caused by Using Bolts W/Insufficient Strength to Attach Stand to Floor

/03L-0:on 831004,valve MOV-R5-255A Became Inoperable When Valve Operator Support Broke Loose from Floor Mounting During Attempt to Cycle Valve.Caused by Using Bolts W/Insufficient Strength to Attach Stand to Floor

ML20132D204
Person / Time
Site:	Surry
Issue date:	11/03/1983
From:	Joshua Wilson VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20132D141	List: 05000281/LER-1983-045-03, /03L-0:on 831008,w/unit Operating at 100% Power, Breaker for Valve MOV-2867D Found Open,Rendering Valve Inoperable.Caused by Accidental Bump While Opening Nearby Fire Door.Breaker Reclosed 05000281/LER-1983-046-03, /03L-0:on 831004,valve MOV-R5-255A Became Inoperable When Valve Operator Support Broke Loose from Floor Mounting During Attempt to Cycle Valve.Caused by Using Bolts W/Insufficient Strength to Attach Stand to Floor ML20132D137
References
LER-83-046-03L, LER-83-46-3L, NUDOCS 8507310245
Download: ML20132D204 (3)

LER-1983-046, /03L-0:on 831004,valve MOV-R5-255A Became Inoperable When Valve Operator Support Broke Loose from Floor Mounting During Attempt to Cycle Valve.Caused by Using Bolts W/Insufficient Strength to Attach Stand to Floor

Event date:
Report date:
2811983046R03 - NRC Website

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4 40 81 DOCKETNvuggm 64 OD EVENT DATE 74 75 REPomT DATE 80 EVENT DESCRIPTION AND PROBA5LE CONSEQUENCES Q l o 121 l With Unit #2 at 100% power. MOV-RS-255A beenwe inonernble uhan the valva nnovnen, l

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ATTACHMENT 1 SURRY POWER STATIO1!, UNIT NO. 2

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DOCKET NO:

50-261 REPORT NO:

83-046/03L-0 EVENT DATE:

10-04-83 TITLE OF THE EVENT: MOV-RS-255A OPERATOR MOUNTING BOLTS SHEARED 1.

Description of the Event With Unit 2 at 100% power during the performance of PT 17.3 (Outside Recire. Spray Pump Test), it was noted that the limits for MOV-RS-255A ('A' OSRS suction valve) were not properly adjusted. While the valve was being cycled, in order to set the proper limits, the valve operator support stand bolts sheared and the valve operator support broke loose from its floor mounting. This rendered the valve inoperable and is contrary to Technical Specification 3.8, Table 3.8.2 and is reportable per T.S.6.6.2.b. (2).

2.

Probable Consequences and Status of Redundant Equipment The OSRS suction and discharge valves remain open during power operations in order to insure the reliability of the OSRS system. However, they must be capable of remote manual closure in the event of a break in the OSRS system during a LOCA.

Since the length of piping in the OSRS system is short and extremely well protected in the valve pit, it is highly unlikely that an OSRS system pipe break would occur simultaneously with a LOCA. Therefore, the health and safety of the public we're not affected.

3.

Cause

The valve motor operator support stand is constructed of a 10" pipe flanged at the bottom with six 9/16 inch concentric bolt holes in the flange in order to bolt the stand to the floor.

The valve operator support broke loose because the 1/4" bolts used in the base were not of sufficient strength to support the shear forces encountered when operating the valve. The 1/4" bolts were installed when the initial installation of DC75-44 (Replacement of OSRS Valves) was installed in 1976. The Design Change package did not provide sufficient detail in specifying the required anchors for the valve operator.

4.

Immediate Corrective Action

The valve was manually closed and the redundant ORS system was verified operable.

5.

Subsequent Corrective Action Six 1/2" dia, by 7" long 'Hilti' concrete anchors were used to attach the stand to the concre;e floor. The valve was verified operable and the ' A' ORS system was returned to service. Also, an engineering evaluation verified that these bolts would be more than adequate to resist all applied forces.

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Report No.

83-046/03L-0 6.

Action Taken to Prevent Recurrence l

Since the installation of the support stands in 1976, many changes have taken place in the design change program and maintenance procedures. These efforts along with increased review procedures and improved support requirements for design work will preclude events of this nature in the future.

7.

Generic Implications An inspection of MOV-RS-255B revealed that three 1/2" bolts were supporting the stand. These bolts have been removed and replaced with sir.

1/2" diameter by 7" long 'Rilti' bolts. The unit 1 valves, MOV-RS-155A and 155B were inspected and each valve uses five 1/2" bolts to secure the stand to the floor. These have been determined to be adequate, however, they will be replaced with six 1/2" 'Hilti' bolts each during the next outage of.

i sufficient duration.

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