ML17074A352

3/29/2017, Entergy Presentation for River Bend Station Pre-submittal Meeting for Control Building Air Conditioning New Technical Specification License Amendment

ML17074A352
Person / Time
Site:	River Bend
Issue date:	03/29/2017
From:	Schenk T A Entergy Operations
To:	Regner L M Plant Licensing Branch IV
Regner L M
References
Download: ML17074A352 (20)

Text

RIVER BEND STATIONPRE-SUBMITTAL MEETINGLicense Amendment Request (LAR): TechnicalSpecification 3.7.7, "Control Building AirConditioning (AC) System"March 29, 20171 OPENING REMARKSTim SchenkRegulatory Assurance ManagerRiver Bend Station2 INTRODUCTIONS3Tim SchenkRegulatory Assurance ManagerRiver Bend Station Agenda4IntroductionTim Schenk-Reg.Assurance ManagerProposed ChangeOverview -HVK and HVCSystemRisk EvaluationClosing CommentsTim Schenk-Reg.Assurance ManagerTim Schenk-Reg.Assurance ManagerPaul Sicard -Sr. Staff PRA EngineerTim Schenk-Reg.Assurance Manager PROPOSED CHANGE5Tim SchenkRegulatory Assurance ManagerRiver Bend Station Proposed ChangeRBS is requesting to add a new Technical Specificationrelated to "Control Building Air Condition (AC) System".This amendment will establish a Completion Time of 14days to allow adequate time to complete maintenanceactivities on the Control Building AC System equipment andthus reduce the need for unnecessary plant shutdowns.6 OVERVIEW -HVK AND HVC SYSTEMTim SchenkRegulatory Assurance ManagerRiver Bend Station7 HVK System DesignSystem DescriptionThe Control Room Air Condition system consists of the heating, ventilating and air conditioning system (HVC) andchilled water system (HVK).Control Building Chilled Water (HVK)Four 100% capacity refrigeration compressors/chillers (2 per division), associated valves, chilled water pumps,service water pumps, instrumentation, and compression tanks.Division I -HVK-CHL1A & HVK-CHL1CDivision II -HVK-CHL1B & HVK-CHL1DThe chilled water system functions during normal, shutdown, and accident conditions to supply chilled water to thecooling coils in HVC-ACU1A/B, HVC-ACU2A/B, and HVC-ACU3A/B.The Normal Service Water system provides cooling water to the chiller condenser. In a DBA or loss of NormalService Water the Standby Service Water system functions as the Ultimate Heat Sink.The Standby Service Water system is also connected to the Chilled Water piping circuit and in the event both trainsof HVK fail it can function as the cooling medium for HVC-ACU1A/B, HVC-ACU2A/B, and HVC-ACU3A/B.The HVK Chillers are safety related and are supplied with power from their respective safety related buss orEmergency Diesel Generator8 9HVK Diagram -Normal Flow Path for 1 of 2Redundant DivisionsACU1A -MainControl RoomFrom ServiceWaterTo ServiceWaterPump 1CPump 1AChiller 1AChiller 1CACU2A -Battery,Switchgear, Inverter,and General AreaACU3A -ChillerEquipment RmTemperatureControl ValveExpansionTankFrom Make-Up Water HVCSystem Design10Control Building HVAC (HVC)Two 100% capacityDivision I -HVC-ACU1A, HVC-ACU2A, & HVC-ACU3ADivision II -HVC-ACU1B, HVC-ACU2B, & HVC-ACU3BThe HVC ACUs function to provide cooling, heating, ventilation to the following areas in the Control Building:HVC-ACU1A/BMain Control RoomHVC-ACU2A/BStandby Switchgear Rooms Cable Chase RoomsGeneral Areas Remote Shutdown RoomsInverter Charger Rooms Battery RoomsHVC-ACU3A/BChiller Equipment RoomsThe HVC ACUs are safety related and are supplied with Power from their respective safety related buss orEmergency Diesel Generator HVC Diagram -Normal Flow Path -1 of 2 Redundant Divisions11 HVCDiagram -Normal Flow Path -1 of 2 Redundant Divisions12 RISK EVALUATIONPaul SicardSenior Staff PRA EngineerRiver Bend Station13 Risk Evaluation: Cont.Bldg.AC TSEvaluated risk (ICCDP and ICLERP) of proposed TS withrespect to RG 1.177 criteria(ICCDP < 10-6, ICLERP < 10-7)Evaluated risk of 14 day outages of HVC and HVK trainsUsed RBS PRA Rev.5-RHU--based on Rev.5 Model of Record--includes improved more rigorous modelling of ControlBuilding room heat-up (RHU) developed 2015-16 toinvestigate chiller risk impactsExternal event risk includedDemonstrated risk of 14 day outages of HVC and HVKtrains meet RG 1.177 criteriaRev 5 Second Dry Run -March 24, 201614 Risk Evaluation: Cont.Bldg.AC TSRBS PRA Rev.5-RHU:accounts for detailed Control Building heatup calculationsperformed 2015uses refined realistic heat loadscredited metal heat sinks in Switchgear Roomscredits battery room fans for Battery andDC Equipment Roomsdetailed equipment survivability studies performed todemonstrate acceptable equipment performanceonly operator action required is to open room doors within4 hours of eventPRA model also credited Service Water direct cooling ofHVC-ACU2A(B)Resulted in low impact on CDF of HVC/HVK trains out ofserviceRev 5 Second Dry Run -March 24, 201615 Risk Evaluation: Cont.Bldg.AC TSICCDP results for 14 day LCO:External Events addressed with multiplier, as done for ILRTsubmittal and in various industry SAMA submittalsIncludes RG 1.177 Common Cause Failure treatmentMeets RG1.177 criteria of <10-6 ICCDP.RBS LERF two orders of magnitude less than RBS CDF.Rev 5 Second Dry Run -March 24, 201616 Risk Evaluation: Cont.Bldg.AC TSRisk of proposed Completion Times smaller than existing TScompletion times.--comparison based on External Events, average maintenanceunavailability assumed, RG 1.177 CCF treatment for HVC/HVK:HVC Div.13.52E-07HVC Div.23.13E-07HVK Div.11.95E-07HVK Div.21.65E-07Service Water A2.71E-06Service Water B1.93E-06HPCS2.87E-07EDG A5.94E-07EDG B7.52E-07EDG C1.42E-06RHR A5.69E-06RHR B2.08E-06Rev 5 Second Dry Run -March 24, 201617 Risk Evaluation: Cont.Bldg.AC TSRBS manages on-line risk per site and corporateprocedures (ADM-0096, EN-WM-104)--protected trains--work only one Division at a time during work weeks--schedule maintenance for <50% of TS LCO timeDefense-in-depth and Safety Margin maintained--no modifications to plant--design criteria maintained--no overreliance on programmatic controls; Loss ofControl Building HVAC procedure calls for electricalequipment room doors to be open <4 hours as onlyrequired recovery actionRev 5 Second Dry Run -March 24, 201618 Risk

Conclusions:

Cont.Bldg.AC TSEvaluated risk (ICCDP and ICLERP) of proposed TSconsistent with RG 1.177 criteriaRisk of 14 day outages of HVC and HVK trainsdemonstrated to meet RG 1.177 criteria (ICCDP < 10-6,ICLERP < 10-7)Used RBS PRA Rev.5-RHUExternal event risk includedSimilar risk as TS LCO's for other systems19 CLOSING COMMENTSTim SchenkRegulatory Assurance ManagerRiver Bend Station20