Information Notice 1986-92, Pressurizer Safety Valve Reliability

Pressurizer Safety Valve Reliability

ML031250138
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, 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, Crane
Issue date:	11/04/1986
Revision:	0
From:	Jordan E L NRC/IE
To:
References
IN-86-092, NUDOCS 8610300067
Download: ML031250138 (4)

SSINS No.: 6835IN 86-92-UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555November 4, 1986IE INFORMATION NOTICE NO. 86-92: PRESSURIZER SAFETY VALVE RELIABILITY

Addressees

All pressurized-water reactor (PWR) facilities holding an operating license ora construction permit.

Purpose

This notice is provided to inform recipients of potentially significant problemspertaining to the reliability, of pressurizer safety valves. It is expected thatrecipients will review the information for applicability to their facilities andconsider actions, if appropriate, to preclude a similar problem from occurringat their facilities. However, suggestions contained in this information noticedo not constitute NRC requirements; therefore, no specific action or writtenresponse is required.

Description of Circumstances

St. Lucie 2:On April 17, 1986 while shut down for refueling, St. Lucie 2 personnel benchtested three pressurizer safety valves that have a technical specification (TS)set point of 2515 +/- 1x psig. Valve V-1200 lifted at 2554 psig (14 psi above themaximum TS set point, valve V-1201 lifted at 2893 psig (353 psi above themaximum TS set point), and valve V-1202 was leaking too much to test. Theproblem with V-1201 was attributed to a hole in the bellows which allowed boricacid to contaminate and corrode the valve internals causing them to bind. Theseat of V-1202 was badly steam cut. The minor set point drift of V-1200 wasconsidered normal for 18 months operation. All valves were repaired beforereplacing them in service.McGuire 1:On September 2, 1986, McGuire 1 reported that a pressurizer safety valve hadlifted at 2375 psig, 85 psi below the 2485 +/- 1% TS required set point. Theprimary system depressurized to 1800 psig before the valve fully closed. Thisevent occurred during pressurization for an inservice leak test. Duringsubsequent bench testing of that valve, the as-found set point was determinedto be 2320 psig. Analysis showed that the three lifts used to determine thevalve set point at the last test were trending downward. Cocking of the spring,probably because of debris under the spring or a burr, was considered to be thecause of the set point "drift." When the spring was properly seated, the setpoint stabilized.8610300067 IN 86-92November 4, 1986 The low pressure at which the valve reclosed is attributed by the licensee tothe setting of the blowdown adjusting ring, which deviated from the vendor'srecommended setting by 137 notches. The remaining pressurizer safety valves onunit 1 were inspected and one other had misadjusted ring settings. Themisadjustment was attributed to on-site readjustment by maintenance personnel.The correctly set rings on the third valve were set by the vendor's representa-tive. Unit 1 valves will be repaired and reset.Unit 2 had two pressurizer safety valves set by the vendor's representative andone set by plant maintenance personnel. The plant technician had recorded thering settings, which were the same as the vendor's recommendation. Therefore,Unit 2 valves were determined to be operable.Arkansas Nuclear One, Unit 2:On September 15, 1986 while at 29% power, ANO 2 experienced a spurious openingand rapid reseating of two pressurizer safety valves, which resulted in anincrease in level and pressure in the quench tank and a 4 psig drop in reactorcoolant pressure. On September 25, 1986 following a reactor trip, quench tankparameters and tail pipe temperatures indicated that one or both pressurizersafety valves had lifted. Licensee tests showed that the setpoints of the valveswere lower than the TS required 2485 psig +/- 1%. One valve lifted at 2365 psigand the other between 2430 and 2455 psig. It was determined that the wrong testequipment had been used to set the lift pressure of the valves at the outageprior to these events. The valve manufacturer sent a representative to the sitewith the correct equipment. The valves have been correctly reset.A search of licensee event reports from January 1, 1983 to the present showsthat 20 other evepts involving 32 valves occurred. The problems were: 18 valveswith set point drift, 12 valves with seat leakage, 1 valve with set pressurehigh and 1 valve designated as inoperable. Attachment 1 contains the detailsof this compilation. Other information on the subject of safety valveperformance and reliability may be found in information notices 86-05;86-05, Supplement 1; and 86-56, the subject of which are main steam safetyvalves.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.4,)!& 5 ectorOivisiji of Emergency Preparednessand Ehgineering ResponseOfficdof Inspection and Enforcement

Technical Contact:

Mary S. Wegner, IE(301) 492-4511

Attachments:

1. Other Pressurizer Safety Valve Problems2. List of Recently Issued IE Information Notices Attachment 1IN 86-92 OTHER PRESSURIZER SAFETY VALVE PROBLEMS FROM 01/01/83 TO PRESENTPLANT NO. VALVESINOPERABLESEQUOYAH 1 1LEAKINGSALEM 2 3SALEM 1 3MILLSTONE 2 1SEQUOYAH 2 1SEQUOYAH 2 1BEAVER VALLEY 1 1SUMMER 1SEQUOYAH 2 1SET POINT DRIFTCALVERT CLIFFS 2 1BEAVER VALLEY 1 1SET POINT DRIFT HIGHFT CALHOUN 1SALEM 2 3SALEM 1 3MILLSTONE 2 1PALISADES 1SUMMER 1YANKEE-ROWE 1SET POINT DRIFT LOWANO 1 1SEQUOYAH 1 1SEQUOYAH 2 3SET PRESSURE HIGHYANKEE-ROWE 1 Attactment 2IN 96-92November 4. 1986UI UUb , INootice No.68-91LIST OF RECENTLY ISSUEDIE INFObMATION NOTICESDate of'55 IV3/86nnsSubijectLimiting AccAutherizat1oIssued toAll power reactorfacilities holdingin OL or CP; fuelfabrication andprocessing facilitiesK6-90t6-e9t6-05Sup. 1e6-25Sup. 186-t8"-tJt6-U686-85Requests To Dispose Of Very 11/3/66Low-Level Radioactive WastePursuant to 10 CFR 20 302Uncontrolled Rod Vlthdrawel 10/16/t6Because Of A Single FailureRain Ste Safety Valve Test 10/16/86Failures And Ring SettingAdjustmentsTraceability And Material 10/15/U6Control of Material AndEquipment, ParticularlyFastenersCompensatory measures For 10/15/U6Prolonged Periods Of SecuritySystem FailuresLoss Ot Offsite Power Upon An 10/10/86Automatic tus TransferClarification Of Requirements 10/10/t6For Fabrication And Export OfCertain Previously ApprovedType t PackagesEnforcement Actions Against 10/3/86Medical Licensees ForWillfull Failure To Reporti satdmisistrationsAll power reactorfacilities holdingan OL or CPAll WR facilitiesholding an OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CP; fuelfabrication andprocessing facilitiesAll power reactorfpcilities holdingan OL or CPAll registered usersof NRC certif iedpackagesAll NRC medicalIIcenseesOL a Operating LicenseCP a Construction PermitUNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D.C. 20555OFFICIAL BUSINESSPENALTY FOR PRIVATE USE. *300FIRST CLASS MAILPOSTAGE 6 FEES PASOUSNRCWASH O.C.PERMIT No G47r : -*I '- r,"O I Y I C.". 1 ],A IT I; -- -:I -% :' -.'.7- ' L '.1' '-