Information Notice 1993-16, Failures of Not-Locking Devices in Check Valves

Failures of Not-Locking Devices in Check Valves

ML031080101
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	02/19/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-016, NUDOCS 9302120052
Download: ML031080101 (12)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 February 19, 1993 NRC INFORMATION NOTICE 93-16: FAILURES OF NUT-LOCKING DEVICES IN CHECK VALVES

Addressees

power

All holders of operating licenses or construction permits for nuclear

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information devices in

notice to alert addressees to problems found with the nut-locking the

certain check valves. It is expected that recipients will review as

information for applicability to their facilities and consider actions, in

appropriate, to avoid similar problems. However, suggestions contained

this information notice are not NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

Trojan Nuclear Plant

shutdown, On December 20, 1991, the Trojan Nuclear Plant was in mode 5, cold licensee) was

for a refueling outage. Portland General Electric Company (the (RHR) pumps.

conducting routine inservice testing of the residual heat removal was lower

While testing the A RHR pump, operators noticed that indicated flow the B RHR

than expected and the B RHR pump was rotating backwards, indicating

pump discharge check valve was leaking.

check

On January 21, 1992, the licensee inspected the B RHR pump discharge fasten

valve. The licensee discovered the nut, washer, and lock wire which

On

the disk to the swing arm (see diagram, Attachment 1) were missing.check valve.

January 28, 1992, the licensee inspected the A RHR pump discharge

The licensee discovered the nut was loose and the lock wire was broken, although the disk nut and washer were in place.

could

The licensee reported this event to the NRC, as a condition that alone needed to

have prevented the fulfillment of the safety function of systems

mitigate the consequences of an accident. The licensee based this

disks

determination on the potential scenario of the discharge check valve valve bodies, for both trains separating from the swing arms, falling into the

and impeding RHR flow.

9302120052 P9 IPo*'ct4 t 9 '3in'/

Ace I//c 0\

IN 93-16 A

February 19, 1993 Vogtle Electric Generating Plant, Unit I

On April 2, 1992, the Vogtle Electric Generating

at 100 percent power. Georgia Power Company (the Plant, Unit 1, was operating

65 percent when the internals of the B" feedwater licensee) reduced power to

(FW) pump discharge

valve failed. The licensee inspected the check valve and discovered check

valve disk and hanger assembly were not in place. the

inspected the downstream piping and found the disk Subsequently, the licensee

wedged in a reducer section

of the pipe. The licensee retrieved two hangar capscrews

hanger capscrew locking device from a downstream and a portion of the

FW heater.

Discussion

Trojan Nuclear Plant

The Trojan Nuclear Plant licensee determined the

failures to be inadequate design of the valve diskroot cause of the check valve

Inadequate disk nut torquing had allowed the nut nut locking device.

to

forth. The free motion at the nut/lock wire interface rotate slightly back and

high cycle fatigue and eventual failure of the lock induced low stress, wire.

caused by flow induced vibration and by normal operational Nut motion had been

of the valve internal components. actuation movement

The licensee believes this problem is limited to

valves actuated frequently or

to cases where the associated piping has undesirable

The valves in question are Copes-Vulcan Model 8C74 flow characteristics.

believes this failure mechanism is not limited to valves. The licensee

similar nut locking device design (i.e., thin gauge Model 8C74 valves, as

model Copes-Vulcan check valves. Licensee repair lock wire) exist in other

consisted of torquing the disk retaining nut and of the check valves

a 1/8-inch cotter pin. replacing the lock wire with

The licensee examined five other Copes-Vulcan valves

had failed. In addition, the licensee torqued all but no other lock wires

all lock wires With cotter pins on the valves examined.retaining nuts and replaced

The licensee modified its check valve inspection

program to require

documentation of the type and condition of all valve

devices, including the extent to which retaining retaining nut locking

nut rotation was limited by

the locking device.

IN 93-16 February 19, 1993 Vogtle Electric Generating Plant

The Vogtle Unit 1 licensee determined the root cause of the check valve

failure to be inadequate procedural guidance on check valve maintenance.

Procedural deficiencies identified included lack of specifications for

(1) capscrew torque requirements; (2) the correct number of hangar capscrews

to be used; and (3) the correct use and/or reuse of hangar capscrew locking

devices. The hangar capscrew locking device, shown in Attachment 2, is a

stainless steel plate used to prevent the inadvertent loosening of the hanger

capscrews. The locking devices undergo plastic deformation during

installation. Reuse of the locking devices results in work hardening of the

material, making it more susceptible to unacceptable levels of cracking. As a

result of procedural deficiencies, some valves were reassembled without

locking devices, or with used locking devices. Locking device failure can

allow the hanger capscrews to loosen and the hanger to separate from the body

of the valve.

Valve failure may also have been partially caused by the use of an incorrect

number of capscrews. The valve body is drilled and tapped to accept three

capscrews. The locking device and hanger shims are predrilled for use with

three capscrews. The disk hangers (also illustrated on Attachment 1) removed

from the Vogtle Unit 1 check valves were drilled for use with only two

capscrews. Both Unit I check valves had previously undergone hanger

replacement, as evidenced by warehouse records. The disk hangers supplied by

Pacific Valve, as stock spares, are blanks which must be drilled at the time

of installation to ensure proper disk/seat alignment. The licensee believes

Pacific Valve may have originally supplied check valves with disk hangers

drilled for use with only two capscrews. This belief was based on an

inspection of a Vogtle Unit 2 check valve. The original disk hanger for the

pre-assembled valve was drilled for use with only two capscrews.

The licensee is revising its check valve maintenance procedure to ensure the

hanger capscrews are adequately torqued and the required locking device is

correctly installed. In addition, Pacific Valve Engineering is being asked to

specify the correct number of capscrews required for integrity of the

hangar/body bolted joint, and to identify any differences between design and

installation configurations.

Related Generic Communication

In Information Notice 81-35, "Check Valve Failures," the NRC discussed an

event similar to the failure at Trojan involving Anchor Darling check valves.

The Anchor Darling check valve failures were attributed to the valve being

assembled with lock wire used as the retaining nut locking device, rather than

a locking pin as shown on the design drawing.

r

IN 93-16 February 19, 1993 This information notice requires no specific action or written response.

you have any questions about the information in this notice, please contactIf

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical, contacts: Eric J. Benner, NRR

(301) 504-1171 Francis Grubelich, NRR

(301) 504-2784 Attachments:.

1. -Copes-Vulcan Check Valve Internals

2. Copes-Vulcan Hanger Capscrew Locking Device

3. List of Recently Issued NRC Information Notices

\ Attachment 1 IN 93-16 February 19, 1993 HANGER CAPSCREWS

DISK HANGER

SWING ARM

DISK

WASHER

LOCK WIRE

NUT

COPES-VULCAN CHECK VALVE INTERKALS

1, b

I

LOCKING TAB

_TX

C

/3oides: IT6L CQL

(

K>

Attachment 3 IN 93-16 February 19, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-15 Failure to Verify the 02/18/93 All holders of OLs or CPs

Continuity of Shunt Trip for nuclear power reactors.

Attachment Contacts in

Manual Safety Injection

and Reactor Trip Switches

93-14 Clarification of 02/18/93 All licensees who possess

10 CFR 40.22, Small source material.

Quantities of Source

Material

93-13 Undetected Modification 02/16/93 All holders of OLs or CPs

of Flow Characteristics for nuclear power reactors.

in the High Pressure

Safety Injection System

93-12 Off-Gassing in Auxiliary 02/11/93 All holders of OLs or CPs

Feedwater System Raw for nuclear power reactors.

Water Sources

93-11 Single Failure Vulner- 02/04/93 All holders of OLs or CPs

ability of Engineered for nuclear power reactors.

Safety Features

Actuation Systems

93-10 Dose Calibrator Quality 02/02/93 All Nuclear Regulatory Com- Control mission medical licensees.

93-09 Failure of Undervoltage 02/02/93 All holders of OLs or CPs

Trip Attachment on for nuclear power reactors.

Westinghouse Model DB-50

Reactor Trip Breaker

93-08 Failure of Residual 02/01/93 All holders of OLs or CPs

Heat Removal Pump for nuclear power reactors.

Bearings due to High

Thrust Loading

93-07 Classification of Trans- 02/01/93 All Licensees required to

portation Emergencies have an emergency plan.

OL = Operating License

CP = Construction Permit

K)

IN 93-16 February 19, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Original signed by

Brian K. Grime3 Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Eric J. Benner, NRR

(301) 504-1171 Francis Grubelich, NRR

(301) 504-2784 Attachments:

1. Copes-Vulcan Check Valve Internals

2. Copes-Vulcan Hanger Capscrew Locking Device

3. List of Recently Issued NRC Information Notices

Reviewed by J. Main, Technical Editor

on 04/24/92 DOCUMENT NAME: 93-16.IN

• SEE PREVIOUS CONCURRENCES

OFC :OEAB:DORS :EMEB:DE :PM:PDV:DRP :PM:PDII:DRP

_____ ____________- ____________- - - -------  :-- - -- - -

NAME :DGarcia* :FGrubelich* :LKokajko* :DHood*

____________ _ _ ___

_----------  :  :

DATE :09/24/92 :10/07/92 :10/09/92 :10/09/92  :

OFC :SC/OEAB:DORS:C/OEAB:DORS :C/OGCB:DWORS D9S,77:

_____ ___________--:----------- -- :------------- ,

NAME :TKoshy* :AChaffee*  :.GMarcus*  :

__

__ __ __ __ __-_ ___-----:

- - - - -- - - - - - .-- --

DATE :11/05/92 :12/07/92  : 02/09/93  : WI/Z/93  :

NECampbell

02/09/93 OFFICIAL RECORD COPY

IN 93-XX

February xx, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Eric J. Benner, NRR

(301) 504-1171 Francis Grubelich, NRR

(301) 504-2784 Attachments:

1. Copes-Vulcan Check Valve Internals

2. Copes-Vulcan Hanger Capscrew Locking Device

3. List of Recently Issued NRC Information Notices

Reviewed by J. Main, Technical Editor

on 04/24/92

• SEE PREVIOUS CONCURRENCES

OFC :OEAB:DORS :EMEB:DE :PM:PDV:DRP :PM:PDII:DRP

_____ ____________ _________ _: _ -----  :-  :

NAME :DGarcia* :FGrubelich* :LKokajko* :DHood*

_____ ____________- __________--- :------- - -  :-- - -- - -

DATE :09/24/92 :10/07/92 :10/09/92 :10/09/92 OFC :SC/OEAB:DORS:C/OEAB:DORS :C/OGCB:DORS :D/DORS

____. ____________: -----  :-:

NAME :TKoshy* :AChaffee* :GMarcus J1i:BGrimet-, :

_____-__ _ __ _- -

__ _ __ __-.-__ -- - _- - -

- - __----

__ - - -

DATE :11/05/92 :12/07/92 2//93 V:  ://93  :

OFFICIAL RECORD # PY

Document Name: oNCHKVX.EJB

Francis Grubelich, NRR

(301) 504-2784 Attachments:

1. Copes-Vulcan Check Valve Internals

2. Copes-Vulcan Hanger Capscrew Locking Device

3. List of Recently Issued NRC Information Notices

Reviewed by J. Main, Technical Editor

on 04/24/92

• SEE PREVIOUS CONCURRENCES

OFC :OEAB:DORS :EMEB:DE :PM:PDV:DRP :PM:PDII:DRP

_- __ - -- __

__ ___-

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__  :-- - -- - -

NAME :DGarcia* :FGrubelich* :LKokajko* :DHood*:

_____ ___________- __________--- :---- - - - - :- - - -- - -

DATE :09/2492 :10/07/92 :10/09/92 :10/09/92 OFC :SC/OEAB:DORS:C/OEAB:DORS :C/OGCB:DORS :D/DORS

_____ ____________- __________---:----- - - -  :-- - -- - -

NAME :TKoshy* :AC)W e :GMarcus :BGrimes

_-& _______--  :-- - ----- -- -- -- --

_____ ____________-

DATE :11/05/92  : AZ/7192  : I /92  : I /92 OFFICIAL RECORD COPY

Document Name: G:\EJB1\INCHKVLV.EJB

Reviewed by J. Main, Technical Editor

on 04/24/92

• SEE PREVIOUS CONCURRENCES

OFC :OEAB:DORS :EMEB:DE :PM:PDV:DRP :PM:PDII:DRP :

_____ ____________-- _- _____-_--- -:----- - - - :-- - -- - -

NAME :DGarcia* :FGrubelich* :LKokajko* :DHood*

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NAME :: :AChaffee :GMarcus :BGrimes

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Document Name: G:\DMG\INCHKVLV.DMG

Reviewed by J. Main, Technical Editor

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