Information Notice 1985-23, Inadequate Surveillance and Postmaintenance and Postmodification System Testing

Inadequate Surveillance and Postmaintenance and Postmodification System Testing

ML031180395
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:	03/22/1985
From:	Jordan E L NRC/IE
To:
References
IN-85-023, NUDOCS 8503210461
Download: ML031180395 (4)

SSINS No: 6835IN 85-23UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555March 22, 1985IE INFORMATION NOTICE NO. 85-23: INADEQUATE SURVEILLANCE AND POSTMAINTENANCEAND POSTMODIFICATION SYSTEM TESTING

Addressees

All nuclear power reactor facilities holding an operating license (OL) or aconstruction permit (CP).

Purpose

This information notice is to alert addressees of several instances pertainingto improper system modifications, inadequate postmodification system testing,and inadequate surveillance testing recently detected at the McGuire nuclearpower facility.It is expected that recipients will review the information contained in thisnotice for applicability to their facilities and consider actions, if appropri-ate, to preclude similar problems from occurring at their facilities. However,suggestions contained in this notice do not constitute NRC requirements; there-fore, no specific action or written response is required.

Description of Circumstances

On November 1, 1984, Duke Power Company (DPC) informed the NRC that the fourRosemont differential pressure transmitters that control the closing of fourisolation valves of the upper-head injection (UHI) system at McGuire Unit 1were improperly installed (i.e., the impulse lines were reversed when theoriginal Barton reverse-acting differential pressure switches were replacedwith Rosemont direct-acting differential pressure transmitters during April of1984). As a result, the UHI isolation valves failed to close during drainingof the accumulator when the water level in the UHI accumulator reached the-setpoint. In addition to the improper installation, the postmodification testingwas limited to a dry calibration method that does not use the actual referenceleg of the accumulator; therefore, the installation error was not detected bythe postmodification test. Consequently, the plant was operated for approxi-mately five months with the UHI isolation valves inoperable.The McGuire UHI system design includes a separate nitrogen accumulator thatsupplies pressurized nitrogen to force the water from the UHI accumulator intothe reactor vessel during the initial phase of a design-basis loss-of-coolantaccident (LOCA). Thus, if a design-basis LOCA had occurred while the UHIisolation valves were inoperable, the UHI system would have been actuated;however, the UHI isolation valves would not have closed when the water in the8503210461 IN 85-23March 22, 1985 UHI accumulator had been depleted. As a result, nitrogen gas could have beeninjected into the reactor vessel during the course of a design-basis LOCA.Under such conditions, and using Appendix K assumptions, DPC's analysis indi-cated that the peak cladding temperature of 2200'F most likely would have beenexceeded and that the worst-case increase in containment pressure could haveresulted in exceeding the design pressure by 2 psi.A related but separate event involved the establishing of the set points forclosing the UHI isolation valves. On February 14, 1984, DPC approved theuse of a dry calibration method, which would establish the trip set point forclosing the UHI isolation valves relative to the bottom of the UHI water accumu-lator tank. However, a 24-inch nonconservative error in the trip set pointoccurred at McGuire Units 1 and 2 when the responsible instrument engineermisinterpreted the tank measurements made by instrument technicians. Becausethe dry calibration method does not use the actual process leg of the UHI accu-mulator, this error was left undetected at both units for several months. Thecalibration error was finally detected on November 2, 1984, while DPC personnelwere taking "as-found" data in response to the previous error involving theincorrect installation of the differential pressure transmitters. The conse-quences of this event would be the early isolation of the UHI water accumulatorduring a design-basis LOCA, resulting in less water being delivered to thevessel than assumed in the analysis.A completely unrelated event involved the inoperability of two of the fouroverpower delta temperature reactor protection channels at McGuire Unit 2.This defect was discovered on November 26, 1984, by a DPC engineer while per-forming a posttrip review of a reactor scram in which signals of the twoaffected channels responded contrary to that expected. This event was causedbecause an electrical jumper was not installed on two of the four overpowerdelta temperature input logic cards. The purpose of the jumper is to ensurethat the overpower delta temperature system provides protection for decreasingtemperature, as might be expected on a steam line break. DPC's surveillancetests only verified that protection would be provided for increasing tempera-ture, but not for decreasing temperature. This defect was left undetected foran unknown period of time, but most likely it had existed since initial plantstartup. Subsequent investigations revealed that in addition to inadequatetesting, there was an absence of instructions and descriptions of the requiredjumpers.The above examples illustrate the need for thorough reviews and detailedattention to plant surveillance and postmaintenance and postmodification tests,to ensure that they accomplish the required verification of system function.

IN 85-23March 22, 1985 No specific action or written response is required by this information notice;however, if you have any questions regarding this notice, please contact theRegional Administrator of the appropriate NRC regional office or the technicalcontact listed below.DieorDivis of Emergency Preparednessand 'ngineering ResponseOffice of Inspection and EnforcementTechnical Contacts: I. Villalva, IE(301) 492-9007H. Dance, RII(404) 221-5533Attachment: List of Recently Issued IE Information Notices

Attachment 1IN 85-23March 22, 1985LIST OF RECENTLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to85-2285-21Failure Of Limitorque Motor-Operated Valves ResultingFrom Incorrect InstallationOf Pinon GearMain Steam Isolation ValveClosure Logic3/21/853/18/8585-20Motor-Operated Valve Failures 3/12/85Due To Hammering Effect85-1985-10Sup. 184-1883-70Sup. 185-1785-1685-15Alleged Falsification OfCertifications And AlterationOf Markings On Piping, ValvesAnd FittingsPosstensioned ContainmentTendon Anchor Head FailureFailures Of UndervoltageOutput Circuit Boards In TheWestinghouse-Designed SolidState Protection SystemVibration-Induced ValveFailuresPossible Sticking Of ASCOSolenoid ValvesTime/Current Trip CurveDiscrepancy Of ITE/Siemens-Allis Molded Case CircuitBreakerNonconforming StructuralSteel For Safety-RelatedUse3/11/853/8/853/7/853/4/853/1/852/27/852/22/85All power reactorfacilities holdingan OL or CPAll PWR facilitiesholding an OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll WestinghousePWR facilitiesholding an OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPOL = Operating LicenseCP = Construction Permit