Information Notice 1996-01, Potential For High Post-Accident Closed-Cycle Cooling Water Temperatures to Disable Equipment Important to Safety

Potential For High Post-Accident Closed-Cycle Cooling Water Temperatures to Disable Equipment Important to Safety

ML031060340
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:	01/03/1996
Revision:	0
From:	Crutchfield D M Office of Nuclear Reactor Regulation
To:
References
IN-96-001, NUDOCS 9512270372
Download: ML031060340 (9)

I January 3, 1996NRC INFORMATION NOTICE 96-01: POTENTIAL FOR HIGH POST-ACCIDENT CLOSED-CYCLECOOLING WATER TEMPERATURES TO DISABLE EQUIPMENTIMPORTANT TO SAFETY

Addressees

All holders of operating licenses or construction permits for pressurizedwater reactors.PurDoseThe U.S. Nuclear Regulatory Commission (NRC) is issuing this informationnotice to alert addressees to the potential for high post accident closed-cycle cooling water system temperatures to disable equipment important tosafety. 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 are not NRC requirements; therefore, no specific action or writtenresponse is required.

Description of Circumstances

On November 14, 1994, the licensee for Fort Calhoun initiated a plant shutdownbecause engineering analysis had shown that the control room air conditioners,which operate in a vapor compression refrigeration cycle, could be disabled bya large primary coolanL system pipe rupture or a main steamline break insidethe containment. Loss of the control room air conditioners could causecertain engineered safety feature equipment in the control room to becomeoverheated. The engineering analysis was initiated during preparations for aservice water system operational performance assessment.At Fort Calhoun, the closed cooling water (CCW) system operates in a closedcycle and transfers heat to the raw water system from various pieces ofequipment, including the containment coolers and the control room airconditioning units. The raw water system operates in an open cycle andrejects the heat to the Missouri River. A large primary coolant system piperupture or main steamline break inside the containment could cause the CCWtemperature to rise rapidly because of the large heat input from thecontainment coolers during these postulated accidents. The licenseecalculated that under design-basis conditions, with the maximum availablecontainment tooling capacity and the minimum permissible heat rejectioncapability of the CCW system, the system temperature could reach a maximum of9512270372 or) 1e ltPOD. ICE 00+-tccJ 9Z9Z-j/0 IN 96-01January 1, 1996 6 °C [187 OF], which exceeds the maximum post accident CCW temperaturespecified in the final safety analysis report (FSAR) and the temperature usedto calculate thermal stress in certain piping segments.The control room air conditioning units, which operate with the condenserrefrigerant in a two-phase equilibrium state, are equipped with rupture discsthat were designed to blow out at a CCW supply temperature of 54.5 °C[130 OF]. If the refrigerant was released, the air conditioning units couldnot be recovered. The licensee does not consider a release of the refrigerantto be a personnel safety concern. However, without any air conditioning, andwith the control room ventilation system operating in the emergencypressurization mode, the control room temperature could increase to levelsthat could hinder operator activities and cause the design temperatures ofsafety-related equipment in the control cabinets to be exceeded.The licensee identified two root causes associated with the design deficiency(Licensee Event Report 50-285/94-010 and supplements):1. The use of an inappropriate methodology to establish the maximum postaccident CCW system temperature.2. The failure to include a maximum condenser temperature for post accidentconditions in the procurement specifications for the air conditioningunits. The procurement specifications gave the normal CCW systemtemperatures.The Fort Calhoun FSAR documented the loss of an emergency onsite power sourceas the most limiting single failure for the CCW system. However, such afailure would reduce containment heat transfer to the CCW system, as well asreduce the heat rejection capability of the CCW system. During preparationsfor the self-assessment, the lirensee identified 'ertain initial equipmentconfigurations that could result in a significant reduction in the heatrejection capability of the CCW system without reducing the potential heattransfer from containment.The licensee justified continued operation until the March 1995 refuelingoutage based on implementation of certain compensatory measures and theexistence of low river water and air temperatures at that time. The licenseesubsequently completed modifications that installed air-cooled condenser unitsfor the control room air conditioning units, increased the minimum design CCWheat rejection capability, and determined that the calculated piping thermalstress was within acceptable limits for post accident CCW transienttemperatures. The licensee has also implemented administrative controls toensure that post-accident CCW temperatures remain within acceptable limitswhile a request for a Technical Specification amendment is pendin IN 96-01January 1, 1996 DiscussionClosed cooling water systems are subject to significant transient temperaturevariations because of the limited system heat capacity and the potential forsubstantial changes in heat addition and heat rejection rates. The complexnature of some such systems may make difficult the correct identification ofthe most limiting potential operating configuration of the system. Certainsafety-related components served by CCW systems, such as air conditioningunits and emergency diesel generators may fail in a non-recoverable manner asa result of temperature transients outside the system design basis. Becausetemperature transients initiated by an accident may affect redundant parts ofthe closed cooling water system, safety-related components in redundant trainsnecessary for mitigation of an accident may be affected.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate Office ofNuclear Reactor Regulation (NRR) project manager.Dennis M. Crutch fieldA' DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts: Steven R. Jones, NRR(301) 415-2833Internet:srj@nrc.govWilliam F. Burton, NRR(301) 415-2853Internet:wfb@nrc.gov

Attachment:

List of Recently Issued NRC Information Noticesi LL_

KJAttachmentIN 96-01January 1, 1996 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to95-5895-5795-5695-5510 CFR 34.20; FinalEffective DateRisk Impact Study RegardingMaintenance During Low-PowerOperation and ShutdownShielding Deficiency inSpent Fuel Transfer Canalat a Boiling-Water ReactorHandling UncontainedYellowcake Outside of aFacility ProcessingCircuitDecay Heat ManagementPractices duringRefueling OutagesFailures of Main SteamIsolation Valves as aResult of StickingSolenoid Pilot ValvesUnexpected Opening of aSafety/Relief Valve andComplications InvolvingSuppression Pool CoolingStrainer Blockage12/18/9512/18/9512/11/9512/06/9512/01/9512/01/9511/30/95Industrial RadiographyLicenseesAll holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All Uranium RecoveryLicensees.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.95-5495-5395-47,Rev. 1OL -Operating LicenseCP -Construction Permit IN 96-01January 1, 1996 DiscussionCCW systems are subject to significant transient temperature variationsbecause of the limited system heat capacity and the potential for substantialchanges in heat addition and heat rejection rates. The complex nature of someCCW systems may make difficult the correct identification of the most limitingpotential operating configuration of the system. Certain safety-relatedcomponents served by closed cooling water systems, such as air conditioningunits and emergency diesel generators (See Licensee Event Report 50-317/93-007for Calvert Cliffs, Unit 1), may fail in a non-recoverable manner as a resultof these temperature transients. Because the temperature transient in theclosed cooling water system may be initiated by a single design-basisaccident, safety-related components in redundant trains necessary formitigation of the accident may be affected.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.Dennis M. Crutchfield, DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts: Steven R. Jones, NRR(301) 415-2833Internet:srj@nrc.govWilliam F. Burton, NRR(301) 415-2853Internet:wfb@nrc.gov

Attachment:

List of Recently Issued NRC Information NoticesDOCUMENT NAME: 96-01.INTech Ed reviewed this document 08/22/95*See previous concurrenceTo receive a copy of this document, Indicate In the box: C'" -Copy without enclosures 'E' -Copy with enclosures N -No copyOFFICE SPLB:DSSA* I PECB:DRPM* I C/PECB:DRPM* I D/1,5 I llNAME SJones WFBurton AEChaffee DMW EfieldDATE 12/ /95 12/ /95 12/ir/95 12/Z/95 12/ /95OFFICIAL RECORD COPY IN 95-xxSeptember xx, 1995 DiscussionCCW systems are subject to significant transient temperature variationsbecause of the limited system heat capacity and the potential for substantialchanges in heat addition and heat rejection rates. The complex nature of someCCW systems may make difficult the correct identification of the most limitingpotential operating configuration of the system. Certain safety-relatedcomponents served by closed cooling water systems, such as air conditioningunits and emergency diesel generators (See Licensee Event Report 50-317/93-007for Calvert Cliffs, Unit 1), may fail in a non-recoverable manner as a resultof these temperature transients. Because the temperature transient in theclosed cooling water system may be initiated by a single design-basisaccident, safety-related components in redundant trains necessary formitigation of the accident may be affected.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 Nuclear-Reactor Regulation (NRR) project manager.Dennis M. Crutchfield, DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts:William F. Burton, NRR(301) 415-2853Steven R. Jones, NRR(301) 415-2833

Attachment:

List of Recently Issued NRC Information NoticesDOCUMENT NAME:S:\DRPMSEC\HICCW*See previous concurrencew s. -_. -a dj.I.8 ---- a..i.... #h. 16-~ It~" -rnnu waithrmet anndtnures'F' -CoDv with enclosures 'N' No copyIU ecIMV *a uvy W .-_ne I....-... r.V ......-.-.--_- --.-OFFICE SPLB:DSSA E ADM:PUB I N PECB:DRPM I E C/SPLB:DSSA I E SC/PECB:DRPMI NNAME SJones* Tech Editor* WFBurton CMcCracken EFGoodwi nvDATE 08/21/95 108/22/95 09/05/95 09/07/95 09/11/95----. .- ---aOlFFTCFPECB:DRPM IE IC/PECB:DRPM II UI/KPMI II..... .--. ....... ..1 ............... -- -NAME RJKiessel* jAEChaffee* JDMC utchfieldDATE 09/1395 19118/ _ 112/ /95 _ _UI-IILIAL KtLUKU Lw'i t \ )IN 95-xxSeptember xx, 1995 DiscussionCCW systems are subject to significant transient temperature deviationsbecause of the limited system heat capacity and the potential for substantialchanges in heat addition and heat rejection rates. The complex nature ofclosed cooling water systems may prevent correct identification of the mostlimiting potential operating configuration of the system. Certain safety-related components served by closed cooling water systems, such as airconditioning units and emergency diesel generators (See Licensee Event Report50-317/93-007 for Calvert Cliffs, Unit 1), may fail in a non-recoverablemanner as a result of these temperature transients. Because the temperaturetransient in the closed cooling water system may be initiated by a singledesign-basis accident, safety-related components in redundant trains necessaryfor mitigation of the accident may be affected.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.Dennis M. Crutchfield, DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts: William F. Burton, NRR(301) 415-2853Steven R. Jones, NRR(301) 415-2833

Attachment:

List of Recently Issued NRC Information NoticesDOCUMENT NAME: S:\DRPM SEC\HI CCW*See previous concurrenceTo receive a copy of this document, Indicate In the box: wCw -Copy without enclosures E" = Copy with enclosures NS -No copyOFFICE SPLB:DSSA E ADM:PUB I N PECB:DRPM l E IC/SPLB:DSSA l E SC/PECB:DRPMI N lNAME SJones* [Tech Editor* lWFBurton ICMcCracken X EFGoodwinDATE 08/21/95 108/22/95 09/05/95 09/07/95 09/11/95OFFICE PECB:DRPM E C/Po&R:DRPM I D/DRPMNAME RJKiessel* AECV'affee DMCrutchfeldDATE 09/13/95 09/ /95 056 09/ /95OFFICIAL RECORD COPY

'--' IN 95-xxAugust xx, 1995 DiscussionClosed cooling water systems are subject to significant transient temperaturedeviations because of the limited system heat capacity and the potential forsubstantial changes in heat addition and heat rejection rates. The complexnature of closed cooling water systems may prevent correct identification ofthe most limiting potential operating configuration of the system. Certainsafety-related components served by closed cooling water systems, such as airconditioning units and emergency diesel generators (See Licensee Event Report50-317/93-07 for Calvert Cliffs, Unit 1), may fail in a non-recoverable manneras a result of these temperature transients. Because the temperaturetransient in the closed cooling water system may be initiated by a singledesign-basis accident, safety-related components in redundant trains necessaryfor mitigation of the accident may be affected.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.Dennis M. Crutchfield, DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts:William F. Burton(301) 415-2853Steven R. Jones(301) 415-2833

Attachment:

List of Recently Issued NRC Information NoticesDOCUMENT NAME:G:\IN\HICCW*See previous concurrenceTo receive a copy of this document. Indicate In the box: 'C, -Copy without enclosures E" -Copy with enclosures AN= No copyFOFFICE JSPLB:DSSA I E ADM:PUB I PECB:DRPM C/SPLB:DSSA SC/PECB:DRPM1NAME SJones* Tech Editor* WFBurton VW 4, CMcCracke r 4_ EFGoodwin ,DATE 08/21/95 08/22/95 09/T/95 09/7 /95 09/J /95IOFFICE IPECB:DRPM 1,I..IC/PECB:DRPM II D/DRPMI 11NAME jRJKiessel IM(IAEChaffee IDMCrutchfel IDATE 109/ 95 6" q 109/ /95 09/ /95OFFICIAL RECORD COPY IN 95-xxAugust xx, 1995 DiscussionClosed cooling water systems are subject to significant transient temperaturedeviations because of the limited system heat capacity and the potential forsubstantial changes in heat addition and heat rejection rates. The complexnature of closed cooling water systems may prevent correct identification ofthe most limiting potential operating configuration of the system. Certainsafety-related components served by closed cooling water systems, such as airconditioning units and emergency diesel generators (See Licensee Event Report50-317/93-07 for Calvert Cliffs, Unit 1), may fail in a non-recoverable manneras a result of these temperature transients. Because the temperaturetransient in the closed cooling water system may be initiated by a singledesign-basis accident, safety-related components in redundant trains necessaryfor mitigation of the accident may be affected.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.Dennis M. Crutchfield, DirectorDivision of Reactor Program ManagementOffice of Nuclear Reactor RegulationTechnical contacts:William F. Burton(301) 415-2853Steven R. Jones(301) 415-2833

Attachment:

List of Recently Issued NRC Information NoticesDOCUMENT NAME:G:\WFB\HICCW*See previous concurrenceTo receive a copy of this document, Indicate In the box: ACT -Copy without enclosures 'E" -Copy with enclosures 'N' -No copy[OFFICE SPLB:DSSA l J 1ADM:PUB I PECB:DRPM I C/SPLB:DSSA SC/PECB:DRPMlNAME SJones A1L ITech Editor WFBurton CMcCracken EFGoodwinDATE 08/21/9 108/ /95 08/ /95 08/ /95 08/ /95OFFICE IPECB:DRPM IIC/PECB:DRPM IID/DRPMI 1INAME RJKiessel AEChaffee DMCrutchfieldDATE 08/ /95 08/ /95 08/ /95OFFICIAL RECORD COPY