Information Notice 2001-14, Problems with Incorrectly-Installed Swing-Check Valves

Problems with Incorrectly-Installed Swing-Check Valves

ML012710212
Person / Time
Issue date:	10/03/2001
From:	Imbro E V Operational Experience and Non-Power Reactors Branch
To:
vsb
References
TAC MA2314 IN-01-014
Download: ML012710212 (6)

1*NUDOCS documents can be accessed at the NRC Public Document RoomsUNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555-0001October 3, 2001NRC INFORMATION NOTICE NO. 2001-14:PROBLEMS WITH INCORRECTLY-INSTALLEDSWING-CHECK VALVES

Addressees

All holders of operating licenses for nuclear power reactors, except those who have ceasedoperations and have certified that fuel has been permanently removed from the reactor vessel.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alertaddressees to swing-check valve problems caused by incorrect installation. It is expected that

recipients will review the information for applicability to their facilities and consider actions, as

appropriate, to avoid similar problems. However, suggestions contained in this information

notice are not NRC requirements; therefore, no specific action or written response is required.

Description of Circumstances

Cooper Nuclear StationWhile trouble-shooting a leaking check valve between the reactor core isolation coolingbarometric condenser and the suppression pool, the licensee determined that a check valve

had been installed rotated 90 degrees away from the orientation recommended by the valve

vendor. According to the vendor's technical manual, the valve should have been installed either

in a horizontal line with the hinge pin centerline vertical or in a vertical line with flow upward.

The staff documents this problem with certain Anderson-Greenwood check valves in Inspection

Report 50-298/98-05 (NUDOCS Accession Number 9809240061).

1*The check valves of concern are designed so that, when installed in a horizontal run of piping,the axis of the hinge is vertical and the check valve disc pivots in the horizontal plane, like a

door. The licensee incorrectly installed the valves with the hinge pin horizontal, so the disc did

not pivot in the horizontal plane as required. The disc face pivoted from a horizontal plane, on

forward flow, to a vertical plane on flow reversal. Therefore, the disc tended to hang open on

reversal and cessation of flow. This effect can be visualized from attached Figure 1, which

shows the relationship of the center of gravity of the disc to the axis of the hinge pin. The

spring shown wound around the hinge pin is intended to close the valve against only the design

frictional and drag forces expected to exist with the hinge pin vertical or with the valve in a vertical run of pipe; it was not designed to overcome the gravitational force that would tend tohold the valve open when the hinge pin axis is horizontal and the valve is in a horizontal run of

pipe.As part of its actions to correct this problem, the licensee identified several other check valvesof this type installed with this incorrect orientation.Palo Verde Nuclear StationThe licensee experienced excessive leakage through some Borg-Warner swing-check valves inthe high-pressure safety injection (HPSI) system. The root cause of the problem was

determined to be an error in valve assembly during the original installation. As a result, the disc

assembly was suspended too low inside the body of the valve. With the disc assembly

suspended too low, the valve might have seated acceptably at first but remained partially open

after forward flow exercised the valve.The improper assembly occurred during plant construction. The licensee removed the internalsof these valves so the valve bodies could be welded into the piping. During reassembly of the

internals, the bonnet retaining ring was threaded into the body until it bottomed. The original

factory assembly process included a step that involved backing out the bonnet retaining ring, after it bottomed in the valve body, until the correct disc height was obtained, as visually

observed through the open ends of the valve body. At Palo Verde, however, the valve had

been installed in the piping and the valve internals could not be observed. Therefore, the disc

height adjustment could not be made during valve reassembly, and the disc remained too low in

the body to engage the seat properly. The NRC staff had addressed this problem in Information Notice IN 89-62, "Malfunction ofBorg-Warner Pressure Seal Bonnet Check Valves Caused by Vertical Misalignment of Disk,"

dated August 31, 1989 (NUDOCS Accession Number 8908240375). After IN 89-62 was

issued, the valve vendor issued maintenance guidance to recommend that measurements of an

internal critical dimension be done to ensure that the disc is in the correct position following

maintenance.Until November 1994, the licensee's maintenance procedure for these check valves did notinclude adequate instructions for ensuring correct vertical positioning of the disc. Once the

problem was diagnosed in 1998, the licensee implemented a plan to identify and correct the

error on all of the HPSI discharge check valves. The NRC staff described the licensee's

actions on this problem in Inspection Report 50-528/529/530 98-14 (NUDOCS Accession

Number 9809090298).

DiscussionAs a result of the installation and maintenance errors discussed in this information notice, somecheck valves did not seat properly. Furthermore, the problems at Cooper and Palo Verde

reveal the importance of timely incorporation of vendor recommendations into work instructions

to ensure that check valves are installed and maintained properly. Specifically, the problems highlight the need to install Anderson Greenwood check valves in accordance with vendorguidance and to ensure that the Borg-Warner check valve disc is in its correct vertical position. This information notice requires no specific action or written response. However, recipients arereminded that they are required to consider industry-wide operating experience (including NRC

information notices), where practical, when setting goals and performing periodic evaluations

under 10 CFR 50.65, "Requirement for Monitoring the Effectiveness of Maintenance at Nuclear

Power Plants." 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./RA Patrick M. Madden Acting for/Eugene V. Imbro, Acting Chief

Operational Experience

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor RegulationTechnical Contacts:Charles Marschall, Region IVRobert Benedict, NRR(817) 860-8185(301) 415-1157 E-mail: csm@nrc.govE-mail: rab1@nrc.gov

Attachments:1. Figure 1. Anderson Greenwood Check Valve

2. Figure 2. Borg-Warner Check Valve With Disk Jammed in Open Position

3. List of Recently Issued NRC Information Notices

ML012710212TEMPLATE NO.=NRR-052*See previous concurrenceOFFICEREXBTech EditorRIVC:EMEBREXBAC:REXBNAMERBenedict*PKleene*CMarschallPKuo*JTappertEVImbroDATE09/06/200109/ 04 /2001 / /200109/26/2001 / /2001 / /2001 Attachment 1 Attachment 2

______________________________________________________________________________________OL = Operating License

CP = Construction PermitAttachment 3 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICES

_____________________________________________________________________________________InformationDate of

Notice No. SubjectIssuanceIssued to

______________________________________________________________________________________2001-13Inadequate Standby LiquidControl System Relief Valve

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those who have ceased

operations and have certified that

fuel has been permanently

removed from the reactor vessel2001-12Hydrogen Fire at NuclearPower Stations7/13/01All holders of operating licensesor construction permits for

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operations and have certified that

fuel has been permanently

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2001-10Failure of Central SprinklerCompany Model GB Series

Fire Sprinkler Heads06/28/01All holders of licenses for nuclearpower, research, and test

reactors and fuel cycle facilities2001-09Main Feedwater SystemDegradation in Safety-Related

ASME Code Class 2 Piping

Inside the Containment of a

Pressurized Water Reactor06/12/01All holders of operating licensesfor pressurized water nuclear

power reactors, except those who

have permanently ceased

operations and have certified that

fuel has been permanently

removed from the reactor vessel2001-08Supplement 1Update on the Investigation ofPatient Deaths in Panama,

Following Radiation Therapy

Overexposures06/06/01All Medical Licensees