Information Notice 1986-72, Failure 17-07 PH Stainless Steel Springs in Valcor Valves Due to Hydrogen Embrittlement

Failure 17-07 PH Stainless Steel Springs in Valcor Valves Due to Hydrogen Embrittlement

ML031250113
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, 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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	08/19/1986
Revision:	0
From:	Jordan E L NRC/IE
To:
References
IN-86-072, NUDOCS 8608150013
Download: ML031250113 (3)

SSINS No.: 6835IN 86-72UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555August 19, 1986IE INFORMATION NOTICE NO. 86-72: FAILURE 17-7 PH STAINLESS STEEL SPRINGS INVALCOR VALVES DUE TO HYDROGEN EMBRITTLEMENT

Addressees

All nuclear power reactor facilities holding an operating license or aconstruction permit.

Purpose

This notice is provided to inform recipients of a potentially significant safetyproblem that could result from the failure of springs in solenoid globe valvesmanufactured by Valcor Engineering Corporation. According to the valve manu-facturer these valve springs may fail when exposed to high temperature reactorcoolant containing hydrogen.It is expected that recipients will review the information for applicabilityto their. facilities and consider action, as appropriate, to preclude a similarproblem from occurring at their facility. However, suggestions contained inthis information notice do not constitute NRC requirements; therefore, no spe-cific action or written response is required.

Description of Circumstances

Difficulties were experienced with the operability of two solenoid-operatedglobe valves (Model V526-6190A, p/n 454660001) in the charging system at theFort Calhoun Station, Unit 1 in August 1985. When shut, the valves could notbe reopened without securing all charging pumps. During a refueling outage inJanuary 1986, the two valves were disassembled and examined to determine thecause of the valve malfunction. It was found that disc guide assembly springsin both valves had undergone complete and catastrophic failure. The springs,which initially had 25 coils, were found in sections of only 1-2 coils. Metal-lurgical analysis of the failed springs attributed the probable cause of failurewas due to hydrogen embrittlement. The spring is made of 17-7 PH stainless steel.Discussion with the valve manufacturer, Valcor Engineering Corporation, revealedthat during 1982-83 one failure occurred at Prairie Island Nuclear GeneratingStation and two failures occurred at North Anna Nuclear Generating Station.These spring failures were also attributed to hydrogen embrittlement.8608150013 IN 86-72August 19, 1986 Discussion:Based on analysis and evaluation of the earlier spring failures, the valvemanufacturer issued a letter in 1983 to affected licensees requesting informa-tion on valve application and advised customers of a potential spring problem.Elgiloy springs were offered on receipt of information confirming use withreactor chemistry fluid or specific customer request. With the occurrence ofthe third similar event, the valve manufacturer is planning to issue a secondletter to affected licensees conservatively recommending that valves with springmaterial of 17-7 PH stainless steel used in borated water or reactor chemistrywater be closely monitored and evaluated for any change in normal operation suchas increased seat leakage or an increase in the time required to change position.These conditions could be attributed to broken springs. The manufacturer hasconcluded that hydrogen embrittlement of stainless steel springs is a complexfunction of high temperature, water chemistry, water flow condition, and time ofexposure to the service condition. Therefore, all such springs made of 17-7 PHstainless steel used in Valcor valves in nuclear power plant may be susceptibleto this failure mode under these conditions and should be considered forreplacement.The above described events are an indication of potential licensee/vendorinterface problem. Based on the information received by the NRC, the vendorwas not completely informed via the purchase specifications regarding the servicecondition to which the valve would be exposed. Further, all users of Valcorvalves were not notified of the initial problem through either oversight by thevendor or as a result of the valves being supplied through an intermediate source.No specific action or written response is required by this information notice.If you have any questions about this matter, please contact the RegionalAdministrator of the appropriate regional office or this office."dward LU Jordan, DirectorDivi io$ of Emergency Preparednessani ngineering ResponseOffice of Inspection and Enforcement

Technical Contact:

L. D. Vaughan, IE(301) 492-8811

Attachment:

List of Recently Issued IE Information Notices Attachment 1IN 86-72August 19, 1986LIS OF RECENrLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to86-71Recent Identified ProblemsWith Limitorque MotorOperators8/19/86All power reactorfacilities holdingan OL or CP86-70Spurious System IsolationCaused By The Panalarm Model86 Thermocouple Monitor8/18/86All GE BWRholding anfacilitiesOL or CP-86-6986-6886-6786-6686-6586-6486-6386-62Scram Solenoid Pilot Valve 8/18/86(SSPV) Rebuild Kit ProblemsStuck Control Rod 8/15/86Portable Moisture/Density 8/15/86Gauges: Recent Incidents AndCommon Violations Of Require-ments For Use, Transportation,And StoragePotential For Failure Of 8/15/86Replacement AC Coils SuppliedBy The Westinghouse ElectricCorporation For Use In ClasslE Motor Starters AndContractorsMalfunctions Of ITT Barton 8/14/86Model 580 Series SwitchesDuring Requalification TestingDeficiencies In Upgrade 8/14/86Programs For Plant EmergencyOperating ProceduresLoss Of Safety Injection 8/6/86CapabilityPotential Problems In West- 7/3186inghouse Molded Case CircuitBreakers Equipped With AShunt TripAll BWR facilitiesholding an OL or CPAll BWRholdingfacilitiesan OL or CPAll NRC licenseesauthorized to possess,use, transport, andstore sealed sourcesAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll PWR facilitiesholding an OL or CPAll power reactorfacilities holdingan OL or CPOL = Operating LicenseCP = Construction Permit