Information Notice 1993-42, Failure of Anti-Rotation Keys in Motor-Operated Valves Manufactured by Yelan

Failure of Anti-Rotation Keys in Motor-Operated Valves Manufactured by Yelan

ML031070501
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:	06/09/1993
From:	Grimes B K Office of Nuclear Reactor Regulation
To:
References
IN-93-042, NUDOCS 9306030147
Download: ML031070501 (12)

"-UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555June 9, 1993NRC INFORMATION NOTICE 93-42: FAILURE OF ANTI-ROTATION KEYS IN MOTOR-OPERATEDVALVES MANUFACTURED BY VELAN

Addressees

All holders of operating licenses or construction permits for nuclear powerreactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this informationnotice to alert addressees to potential problems resulting from the failure ofanti-rotation keys in motor-operated globe valves manufactured by Velan ValveCorporation. It is expected that recipients will review the information forapplicability to their facilities and consider actions, as appropriate, toavoid similar problems. However, suggestions contained in this informationnotice do not constitute NRC requirements; therefore, no specific action orwritten response is required.

Description of Circumstances

On March 28, 1993, Wisconsin Public Service Corporation, the licensee forKewaunee Nuclear Power Plant, reported that during motor-operated valve (MOV)dynamic testing on March 27, 1993, one of two redundant safety injectionrecirculation valves to the refueling water storage tank failed to closecompletely. Investigation revealed that the anti-rotation device, an L-shapedkey between the valve stem and the yoke bushing (Attachment 1), had broken.The shorter part of the broken L-shaped key had apparently worked its waytoward the valve stem and had jammed the valve stem, preventing closing. Thevalve that failed was a 2-inch bonnetless globe valve manufactured by VelanValve Corp. The licensee inspected all nine similar motor-operated valves andfound that six had broken anti-rotation keys. The inspections were visual anddid not require disassembly of the motor-operated valve. Failures usually canbe observed on normally closed valves, since the broken long leg of theL-shaped key slides down partially and becomes visible below the yoke bushing.According to the licensee, the keys failed in a brittle manner. The fracturesbegan on either side of the key at the sharp radius of the inside corner ofthe L-shaped key and propagated into the body of the key. Machining of thesharp inside corner of the L-shaped key may have contributed to the failure ofthe anti-rotation keys by producing high stresses in the corner of the keys.It is likely that the rotational action of the valve stem impacted on bothsides of the key, exceeding the impact strength of the material at the sharpradius of the key.9306030147 POR SIE Wr;c-c 913o0&i 93o0wt41 ' C1301q3 in le- // A IN 93-42June 9, 1993 In 1990, at the Maine Yankee Atomic Power Station, anti-rotation keys in4-inch MOVs manufactured by Velan failed. Maine Yankee Atomic Power Company,the licensee, discovered that spare keys supplied by Velan for several of thevalves were not of the proper hardness; they were Rockwell C-20 instead of theharder Rockwell C-59 as originally specified. Valves that may have had thewrong anti-rotation keys installed were disassembled, and the licenseereplaced the Rockwell C-20 keys with keys made of the correct material. Thenon-conforming keys that were removed showed signs of significant wear.During post-maintenance testing, several of the new (hardened) keys broke atthe corner of the 'L" shape. This happened because the keyway in the valveadaptor plate was too tight considering the service-related wear that hadoccurred to the rest of the keyway. Maine Yankee engineers specified that newlarger keyways should be cut in the adaptor plate to prevent the key frombreaking when the valve is actuated. The licensee repaired all the affectedvalves and then tested the valves to ensure that they operated satisfactorily.Before testing MOYs at Prairie Island this past winter, an inspection of Velanglobe valves also discovered anti-rotation key failures (2 broken keys foundin 16 valves) in similar systems. Because of the location of the break on theanti-rotation key, and the length of the key and key slot, Northern StatesPower Company, the licensee, believed that the broken anti-rotation keys wouldstill perform their intended function and that the broken piece (i.e., theshort leg of the L-shaped key) would not interact with the valve stem so as toimpede valve operation. This is at variance with the Kewaunee event discussedabove. The licensee added a step to their generic actuator replacementprocedure to inspect, clean, debur, and lubricate anti-rotation devices.DiscussionOn April 5, 1993, Velan issued the attached (Attachment 2) Service Bulletin#SB-106. This bulletin recommends that the anti-rotation keys be inspectedfor possible wear which could result in failure and that consideration begiven to replacing the keys at the earliest convenient time. The replacementkeys, which have been supplied by Velan for the past 24 years, are made ofmaterial meeting American Iron and Steel Institute (AISI) 4140 alloy steel, asopposed to 440C stainless steel (440C SS). AISI 4140 is significantly tougherthan 440C SS. According to Velan, the material was changed to 4140 because4140 is easier to procure and to heat treat properly. Velan plans to sendthis bulletin to all U.S. nuclear utilities. On the basis of conversationsbetween the NRC staff and Velan subsequent to the issuance of the bulletin,and because of the hardness of anti-rotation keys made out of 440C SS, Velansuggests that both the keys and the keyways be inspected for damage anddeterioration. The experience cited above indicates that the use of brittlematerial in anti-rotation keys can lead to failures, although valve operationmay not always be impaired._ a IN 93-42June 9, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:David C. Fischer, NRR(301) 504-2728

Attachments:

(' w )1. Figure 1, Velan Valve and Anti-Rotation Key2. Velan Service Bulletin #SB-1063. List of Recently Issued NRC Information Notices N-Attachment 1IN 93-42June 9, 1993 VELAN VALVE AND ANTI-ROTATION KEYSTEM,1 1/X_ 5 ACME-2G-L.H.PITCH: .200LEAD: .200BUSHINGKEYWAYVALVE.,BUSHINGSTEM Attachment 2-_ IN 93-42June 9, 1993 _,VEAS-SERVICE BUlll ~- I#SB-1i

SUBJECT: -GLOBE VALVE STEM ANTROAIIO KEYThis is to advise you that an "LI shaped, globe valverotation key failed at Kewaunee Nuclear Plant. The valveis a 2; Motor operated globe valve originally supplied137.116/1.stem anti-in questionto drawingThe valves affected are those Motor Operated Globe valves requiring akey installed in mounting flange which prevents the stem fromrotating. Globe valves which have been supplied with torque arms arenot affected by this failure.Based on the incident at Kewaunee Nuclear Plant we recommend that keysbe inspected for possible wear which could result in failure.Consideration should also be given to replacing keys at your earliestpossible convenience with new keys. These new keys are supplied inmaterial meeting AISI 4140. This material replaces the 440C gradewhich several project drawings call up.Replacement keys which have been supplied by us during the last 2 1/2years have been from this new material. If these have been installed,only regular periodic verification will be required. If no inspectionand or replacements has been made, we recommend that key. be replaced.For additional information or replacement keys, please contact:Velan valve Corp.550 McArthurMontreal, QuebecH4T 1X8Attn t Nuclear DivisionPhone: 514-748-7743Pax s 514-342-2311Ic -esident, Quality AssuranceNilaeonManager, nuclearDivision-pa--. I p--v..My: 3.1. Francois 0 1 of 1I'Tiril 5f 1993By l .I. Francois Ilew0o1"..1 of 1I

'-IAttachment 3IN 93-42June 9, 1993Page l'of ILIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to93-4193-4093-3993-3893-3793-3693-3593-34,Supp. 1One Hour Fire EnduranceTest Results for ThermalCeramics Kaowool, 3MCompany FS-195 and3M Company Interam E-50Barrier SystemsFire Endurance TestResults for ThermalCeramics FP-60 FireBarrier MaterialRadiation Beams fromPower Reactor Biolog-ical ShieldsInadequate Testing ofEngineered SafetyFeatures ActuationSystemEyebolts with Indeter-minate Properties In-stalled in LimitorqueValve Operator HousingCoversNotifications, Reports,and Records of Misadmin-istrationsInsights from Common-Cause Failure EventsPotential for Loss ofEmergency CoolingFunction Due to ACombination ofOperational and Post-Loca Debris in Contain-ment05/28/9305/26/9305/25/9305/24/9305/19/9305/07/9305/12/9305/06/93All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All U.S. Nuclear RegulatoryCommission medicallicensees.All holders of OLs or CPsfor nuclear power plants(NPPs).All holders of OLs or CPsfor nuclear power reactors.OL = Operating LicenseCP = Construction Permit IN 93-42June 9, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Original signed byBrian K. GrimesBrian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:David C. Fischer, NRR(301) 504-2728

Attachments:

1. Figure 1, Velan Valve and Anti-Rotation Key2. Velan Service Bulletin #SB-1063. List of Recently Issued NRC Information Notices*See previous concurrence sheet*EMEB:DE:NRRDCFischer4/15/93*C/EMCB:DE:NRRJRStrosnider4/20/93*OGCB:DORS:NRRRJKiessel05/03/93*SC/EMEB:DE:NRREJSullivan4/16/93*C/RVIB:DRILLJNorrholm4/20/93*C/OGCB:DORS:NRRGHMarcus05/12/93*RPB:ADMTechEd4/15/93*C/EMEB:DE:NRRJANorberg4/19/93*D/DE:NRRJERichardson4/23/93I0*DRS:RIIIGCWright4/21J.3II /93DOCUMENT NAME: 93-42.IN IN 93-XXApril 22, 1993 Even though a broken anti-rotation key does not always impair valve operation,it is a concern to the NRC that anti-rotation keys made of such brittlematerial (440C SS) are used in safety-related valves.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:David C. Fischer, NRR(301) 504-2728

Attachments:

1. Figure 1, Velan Valve and Anti-Rotation Key2. Velan Service Bulletin #SB-1063. List of Recently Issued NRC Information NoticesDocument Name:*See previous concurrence sheet*EMEB:DE:NRRDCFischer4/15/93*SC/EMEB:DE:NRREJSullivan4/16/93*RPB:ADMTechEd4/15/93*C/EMEB:DE:NRRJANorberg4/19/93*C/EMCB:DE:NRRJRStrosnider4/20/93*C/RVIB:DRILLJNorrholm4/20/93*DRS:RIIIGCWright4/21/93*D/DE:NRRJERichardson4/23/93OGCB:DORS:NRRRJKiessel/ /93C/OGCB:DORS:NRRGHMarcusHkiMf /taL/93D/DORS:NRR rBKGrimes -/ /93 u IN 93-XXApril 22, 1993 Even though a broken anti-rotation key does not always impair valve operation,it is a concern to the NRC that anti-rotation keys 'made of such brittlematerial (440C SS) are used in so many safety-related valves.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact: David C. Fischer, NRR(301) 504-2728

Attachments:

1. Figure 1, Velan Valve and Anti-Rotation Key2. Velan Service Bulletin #SB-1063. List of Recently Issued NRC Information NoticesDocument Name:*See previous concurrence sheet*EMEB:DE:NRRDCFischer4/15/93*SC/EMEB:DE:NRREJSullivan4/16/93*RPB:ADMTechEd4/15/93*C/EMEB:DE:NRRJANorberg4/19/93*C/EMCB:DE:NRRJRStrosnider4/20/93*C/RVIB:DRILLJNorrholm4/20/93*DRS:RIIIGCWright4/21/93*D/DE:NRRJERichardson4/23/93OGCB:DORS:NRRRJKiessel/ /93C/OGCB:DORS:NRRGHMarcus/ /93D/DORS:NRRBKGrimes/ /93 114rIN 93-XX-Paige3, 1993 hardness of anti-rotation keys made out of 440C SS, Velan suggests that boththe keys and the keyways be inspected for damage and deterioration.Even though a broken anti-rotation key does not always impair valve operation,it is a concern to the NRC that anti-rotation keys made of such brittlematerial (440C SS) are used in so many safety-related valves.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:David C. Fischer, NRR(301) 504-2728

Attachments:

1. Figure 1, Velan Valve and Anti-Rotation Key2. Velan Service Bulletin #SB-1063. List of Recently Issued NRC Information NoticesDocument Name:*See previous concurrence sheet*EMEB:DE:NRRDCFischer4/15/93*SC/EMEB:DE:NRREJSullivan4/16/93*RPB:ADMTechEd4/15/93*C/EMEB:DE:NRRJANorberg4/19/93*C/EMCB:DE:NRRJRStrosnider4/20/93*C/RVIB:DRILLJNorrholm4/20/93*DRS:RIIIGCWright4/21/93*D/DE:NRRJERichardson4/23/93OGCB:DORS:NRR4,RJKiesselg/gJ/93 MQ<C/OGCB:DORS:NRRGHMarcus/ /93D/DORS:NRRBKGrimes/ /93 Document Name:G:\FISCHER\VELAN.INEMEB:DE:NRR 8 :NRRDCFischer EJSe 1yn9 /ir/93 4/l /CDoo t1-1 1I.c"641Ott FRvRPB:ADMTechEdV /f/93lee OmILA/ /3IDRS :R I I I'346sGCWright4 /'i /93C:& rgRRD: DE: NRRJERichard nt/N~3/93OGCB:DORS:NRRRJKiessel/ /93C/OGCB:DORS:NRRGHMarcus/ /93D/DORS:NRRBKGrimes/ /93