ML13238A054

08/19/2013 Meeting Summary - Category 1 Public Meeting Regulatory Conference, H.B. Robinson Steam Electric Plant, Docket No. 50-261

ML13238A054
Person / Time
Site:	Robinson
Issue date:	08/23/2013
From:	Hopper G Division Reactor Projects II
To:	William Gideon Duke Energy Carolinas
References
EA-13-129
Download: ML13238A054 (56)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 245 PEACHTREE CENTER AVENUE NE, SUITE 1200 ATLANTA, GEORGIA 30303

-1257 August 2, 2013 EA-13-129 Mr. William R. Gideon Vice President Duke Energy H. B. Robinson Steam Electric Plant, Unit 2 3581 West Entrance Rd Hartsville, SC 29550

SUBJECT:

MEETING

SUMMARY

- CATEGORY 1 PUBLIC MEETING - REGULATORY CONFERENCE, H.B. ROBINSON STEAM ELECTRIC PLANT, DOCKET NO.

50-261

Dear MR. Gideon,

This refers to the meeting conducted at your request at the NRC Region II Office on August 19, 2013, at 10:30am, Eastern Time. The purpose of this Regulatory Conference was for you to present to the NRC your perspectives on the facts and assumptions used by the NRC to arrive at the finding and the significance stated in the Inspection Report (IR) 05000261/2013008. This meeting also provided you an opportunity to provide other information you believe the NRC should take into consideration before making an enforcement decision.

Enclosed are a list of attendees (Enclosure 1) and the presentation handouts (Enclosure 2).

The topics discussed included Duke Energy's position with regard to the preliminary White finding documented in IR 05000261/2013008. This preliminary White finding was associated with an apparent violation (AV) of 10 CFR 50.63, "Loss of All Alternating Current Power", as a result of the licensee's failure to inspect the dedicated shutdown diesel generator radiator fan belts in accordance with the vendor's recommended maintenance guidelines. We will consider the information you provided prior to making an enforcement decision.

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room (PDR) or from the Publicly Available Records (PARS) component of NRC's Agency

-wide Document Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/NRC/ADAMS/index.html (the Public Electronic Reading Room).

W. Gideon 2 Should you have any questions concerning this conference, please contact me at 404.997.4645. Sincerely, /RA By James Dodson For/

George Hopper, Chief Reactor Projects Branch 4 Division of Reactor Projects

Docket No.:

50-261 License No.:

DPR-23

Enclosures:

1. List of Attendee 2. Duke Energy Presentation Slides

cc: Distribution via Listserv

___

______ SUNSI REVIEW COMPLE FORM 665 ATTACHED OFFICE RII:DRP RII:DRP SIGNATURE /RA/ /RA/ NAME SHerrick JDodson DATE 8/20/2013 8/20/2013 E-MAIL COPY?

YES NO YES NO YES NO YES NO YES NO YES NO YES NO W. Gideon 3 Letter to William R. Gideon from George Hopper dated August 2, 2013

SUBJECT:

MEETING

SUMMARY

- CATEGORY 1 PUBLIC MEETING - REGULATORY CONFERENCE, H.B. ROBINSON STEAM ELECTRIC PLANT, DOCKET NO.

50-261 DISTRIBUTION: OEMAIL OEWEB Region II Regional Coordinator NRR Enforcement Coordinator Enforcement Officer and Regional Counsel, RII Public Affairs Officer, RII Chief, Resource Management Branch, RII Region II Administrator's Secretary DRP Division Secretary Region II Division Directors and Deputies Region II Receptionist Headquarters Operations Officer NRR DISP/PIPB (reactor cases)

L. Douglas, RII, EICS RIDSNRRDIRS RidsNrrPMRobinson Resource PUBLIC Enclosure 1 List of Attendees NRC L. Wert, Deputy Regional Administrator, RII C. Evans, Regional Counsel, RII S. Sparks, Senior Enforcement Specialist, RII R. Croteau., Director, Division of Reactor Projects (DRP) W. Jones, Deputy Director, DRP H. Christensen, Deputy Director, Division of Reactor Safety (DRS)

G. Hopper, Chief, DRP, Reactor Projects Branch (RPB) 4 C. Scott, Acting Senior Resident Inspector, Robinson, RII

J. Hickey, Chief, Division of Fuel Facility Inspection, Fuel Facility Branch 2, RII J. Dodson, Senior Project Engineer, DRP, RPB 4 S. Herrick, Project Engineer, DRP, RPB 4 G. MacDonald, Senior Reactor Analyst, RII J. Circle, Senior Reliability and Risk Analyst , HQ Call-in attendees:

M. Halter, Office of Enforcement, HQ L. Casey, Office of Enforcement, HQ K. Ellis, Senior Resident Inspector, Robinson, RII DUKE / Robinson P. Gillespie, Senior Vice President Nuclear Operations R. Gideon, Site Vice President T. Cosgrove, Plant General Manager J. Kammer, Director, Engineering K. Holbrook, Manager, Operations D. Douglas, Manager, Maintenance

B. Rishel, Manager, Probabilistic Risk Analysis J. McCrory, Senior Engineer, Probabilistic Risk Analysis R. Hightower, Supervisor, Licensing

C. Nolan, Director, Corporate Regulatory Affairs

Call-in attendee:

D. Cummings, Associate General Counsel Public (call-in)

R. Thomas S. Cownoley S. Threatt, State of SC T. Mc Kinney, State of SC

Robinson Nuclear PlantDedicated Shutdown Diesel Fan Belt Performance DeficiencyAugust 19, 2013 Regulatory Conference Duke ParticipantsPreston GillespieSenior Vice President, Nuclear OperationsRandy GideonSite Vice PresidentMike GloverDirector, Site OperationsTom CosgrovePlant General ManagerJim KammerDirector, EngineeringJohn LittleManager, Shift OperationsDonnie Douglas Manager, MaintenanceBob Rishel Manager, Probabilistic Risk AnalysisRichard HightowerSupervisor, LicensingChris NolanDirector, Regulatory Affairs AgendaOpening RemarksR. GideonDSDG Design and TimelineJ. KammerOperations ResponseJ. LittleMaintenance ResponseD. DouglasSignificance DeterminationB. RishelCause Analysis & Corrective ActionsT. CosgroveRegulatory PerspectiveM. GloverClosing RemarksP. Gillespie Opening RemarksRobinson agrees with the apparent violation described in the NRC's letter dated July 1, 2013Robinson understands the importance of the Dedicated Shutdown Diesel-Generator (DSDG)Performance did not meet our expectations for maintaining the DSDGRoot Cause Evaluation performedKey drivers contained in the Probability Risk Assess ment (PRA):Mitigation measures to maintain secondary side coolin gHigh probability of success for fan belt replacementPostulated damage from arc faulting in 480V cabinetsDuke Energy's analysis concludes that the Finding is of very low safety significance Dedicated Shutdown Diesel GeneratorDesign and TimelineJim KammerRobinson Engineering Director Robinson Design TopicsDSDG DesignRelevant Robinson Design FeaturesDSDG Belt Failure TimelinePostulated Events affected by DSDG Belt FailureOverall Postulated Event Timeline DSDG DesignDSDG installed in 1981The DSDG provides a source of electrical power to br ing the plant safely to a hot shutdown condition in the event of a fireDSDG automatically provides an emergency source of electrical power in the event of a simultaneous loss of all off-site power and both EDGs Design FeaturesEmergency AC Power 480V Emergency Power System versus more typical 4160 V systemsAmptectorsare installed on Emergency Bus E1 and E2 Supply BreakersSpatial separation results in Emergency Bus E1 High Energy Arc Fault (HEAF) not directly impacting Emergency Bus E2 and vice versaIn the Cable Spread and Emergency Switchgear Rooms, fire retardant coating is applied to cables in tray that are not flame spread rated Instrumentation Instrumentation required for Operators to assess and maintain secondary side heat removal does not rely on power from Dedicated Shutdown (DS) BusSteam Driven Auxiliary Feedwater Pump flow indicatio n does not rely on power from the DS BusRadio communications do not rely on power from the DS Bus DSDG Belt Failure TimelineAug 28 1808Oct 2 1703 Oct 2 1623Oct 2 1648Closed breaker 52/32B and loaded the DSDGStarted DSDG unloaded from the DSDG enclosure per monthly OST-910DSDG automatic shutdown on high temperatureDSDG successfully tested per OST-910 Postulated Fire Events Affected by DSDG Belt FailurePostulated large fire affecting onsite power distributionDominates both Duke and NRC Risk Significance Analys i sPostulated loss of Offsite and Emergency AC power internal to power block onlySupport facilities would continue to receive AC power from retail distribution system Postulated Fire Event Timeline~ !"#%&

Operations ResponseJohn LittleRobinson Manager -Shift Operations Operations Response -OverviewOperators would maintain adequate heat sink capability for core decay heat removalProcedural DirectionTrainingPeriodic ExaminationsOperator FundamentalsOperators would respond to the fire using AOP-041, R esponse to a Fire Event and DSP-001, Alternate Shutdown DiagnosticBased on postulated fire location or procedural progression, both emergency buses and offsite power are assumed to be unavailable Operations Response -OverviewDepending on the limiting event, Operators would respond withDSP-002, Dedicated Shutdown Procedure -Hot Shutdown Using the Dedicated/Alternate Shutdown SystemEPP-1, End Path Procedure -Loss of All AC PowerFor the purposes of this discussion, DSP-002 response is more limitingCooldownrateDSP-002 -25°F/hrEPP-1 -100°F/hrDSP-002 exposes RCP seals to elevated temperature fo r a longer period of timeOther factorsRequires control of the plant from local control sta tionsCommunications and direction via radio Operations Response -Procedural RequirementsOperators will maintain Auxiliary Feedwater flow ensuring the critical safety function for heat sink -300 gpmAuxiliary Feedwater (AFW) flow or minimum of 8% SG narrow range (60% wide range) levelProcedure steps direct maintaining heat sink early i n response:EOP-E-0, Reactor Trip or Safety Injection, steps 6 through 8 (prior to entry into DSP-002)EPP-1, step 7DSP-002, Attachment 1, Turbine Building Operator, st eps 6 and 7 Operations Response -Anticipating Plant Response Stable cooldownrate with valve position procedurally established via DSP-002 prior to DS battery depletionDSP-002 implements DSP-007, Cold Shutdown Using DS S ystemDS Battery Depletion occurs in One HourIncluded in procedural basis in multiple proceduresEO P-E-0OP-602, Dedicated Shutdown SystemOperators would expect effects of depletion of DS ba ttery after trip of the DSDG and would have one hour to prepareBased on related proceduresFeedwater flow will continue for heat sink Operations Response -Reinforced by TrainingDedicated Shutdown (DS) Procedural Strategy included as part of Operator Initial Training CurriculumContinuing Training BackbonePrior to DSDG Belt FailureDSP-002, last completed August 2011EPP-1, last completed June 2012 Operations Response -Reinforced by TrainingImportance of DS strategy including DSDG reflected by frequency they appear in Licensed Operator Job Performance Measure (JPM) annual exams:2009 -Local SG PORV control2009 -Energizing DS Bus using DSDG per DSP-0022010 -DeenergizingEmergency Buses per DSP-0022010 -Manual Start of the DSDG per EPP-12012 -Manual Start of DSDG per DSP-002 (after AUTO st art mod)2012 -Respond to a loss of all AC Power EPP-1 (AFW Flow)2013 -Start CCW Pump A, Control Charging Pump A locally per DSP-002 DSP-002, Alternate Hot Shutdown System ProcedureOperations personnel proceed t o the pre-arranged muster location DSP-002, Alternate Hot Shutdown System ProcedureRadios, portable lights and controlled procedures maintained in the muster locationRadio communication between operators has been

d emonstratedChannel 2 does not require use of repeaterSuccessfully Tested at NRC request -2007 Triennial Fire Protection Inspection (IP 71111.05); from Muster Location to Charging pump room on channel 2 without need for repeater (11/07/07)Functionality tested monthly per OST-639, Fire E quipment InventoryTest successfully repeated on 08/07/13:Muster location to Secondary Control Panel, Charging Pump Room, and SI Pump RoomIf Shift Manager goes to Work Control, communicates to Charging Pump Room via Secondary Control Panel Operator Secondary Control StationOperators control the plant at the s econdary control stationLocation where cooldownestablishedNatural circulation including subcooling checked at step 10 of DSP-002, Att. 1 AFW Flow Control ValvesOperators control AFW flow using valves adjacent to the control panel to maintain the secondary heat sinkA stable cooldownrate with associated

v alve position via DSP-002 would have been attained by the time of DS battery depletion Indications Used for ControlSecondary Control Station -Multiple indications available at the start of the postulated scenario and for one hour on the DS batteries after DSDG tripSG Level (all three SGs)Pressurizer (PZR) LevelPressurizer PressureCondensate Storage Tank Level"A" RCS Cold Leg Temperature"A" RCS Hot Leg TemperatureIndications remaining after battery depletionAFW flow via FT-6416 -1 stlevel Turbine B uildingSG Pressure -Secondary Control Station Secondary Control StationOperators use the indication of SG pressure (left) and the curve from DSP-002 (right) to correlate and control RCS cold leg temperature and ensure decay heat removalIndications of pressure for a ll three steam generators would remain availablepurely mechanical, no electrical power necessarySG level indication not

n ecessaryFT-6416 -Local Feed Flow indication, first level turbine building (center), remains available, electrical power not required Response to DSDG High Temperature TripOperators will maintain feedwater flow ensuring critical safety function of heat sink for decay heat removalAFW flow procedurally driven to 300 gpmm inimumSG levels procedurally established and maintained between 60 and 68%Stable cooldownrate of 25°F/hour after entry into DSP-002Operator have the procedures, training, indications, and fundamental knowledge to successfully maintain decay heat removalPerformance of DSP-002 provides a success pathFlow rates to the SG are relatively stable when DS B attery is depletedVapor volume of SGs sufficient to prevent overfill after loss of level indicationSG Overfill will not occur in the postulated scenari o

Operations Success CreditOperator actions will succeedProcedures direct continued flow to the steam genera torsAvailable indications will be used to ensure SGs remain viable as a heat sink throughout the postulated scenarioOperator actions to maintain flow have been in progress prior to the loss of SG indication and will continue after the lossRequired only to continue feed flow and steaming mon itoring SG pressureTraining and examinations reinforce continued flow to the steam generatorsEffective Radio communications demonstrated Maintenance ResponseDonnie DouglasRobinson Maintenance Manager Maintenance ResponsePersonnel will respond to the ERO notificationParts needed to repair the DSDG are readily obtained with or without computer resources or other supportEmergent Work Order using station process is designed for this type of situationDSDG repair will succeed in required timeframeStraightforward tasksSimple, readily available tools Maintenance Response Strategy to Postulated Fire Event$'()+$~+$%,+"+&%#%+&+

Maintenance ResponseMaintenance actions start to recover D SDG:Within 60 minutes of the start of the scenario:Maintenance personnel arrive on siteMissions to locate replacement belts

a nd remove belt guard underway Maintenance ResponseWithin 120 minutes of the start of the s cenario, Maintenance have obtained the replacement belts Maintenance ResponseWithin 120 minutes of the start of the s cenario, Maintenance would have the guard off and the belts removed Maintenance Success CreditHigh Probability of SuccessEmergency Response to fill two teamsIdentifying/Acquiring Partscore skilltrial scenariosday and night acquisitionEmergent Work Order processpracticed in Emergency dr ills/exercisesBelt replacement is a simple and frequent task181 Work Order tasks performed over past 5 years associated with belt replacements or adjustments with one condition report for rework Significance DeterminationBob RishelPRA Manager Significance Determination -OverviewRobinson Basis for Very Low Safety Significance1.Plant design and configuration of DS cables/HEAF sources make loss of DS Bus unlikely Impact of 480V HEAF is smaller when compared to a 4 160V HEAF2.Recovery CreditOperators establish/maintain SGs feed and cool down rates before DS battery depletion occursOperators maintain heat sink after DS battery deplet ionMaintenance recovery of DSDG The belt repair straightforward with simple tools HEAFs in Robinson E1 SwitchgearRobinson 480V HEAF considerations1.480V E1 and E2 switchgear robust cabinet construction Solid topsCabinets are secured with thread fasteners in corner sSupply breakers are in lower half of cabinetOutgoing load breakers are protected with Amptectors2.E2 cables and DS Bus cables are outside the Zone of Influence (ZOI) for E1 HEAF from supply breakers3.No E2 damage from E1 HEAFNo loss of DS Bus due to E1 HEAF Emergency Bus Configuration -Looking South&$&~&$

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Significance Determination ContributionsRobinson Incremental Conditional Core damage Probability (ICCDP) contribution from the E1 HEAF is <1E-08 This is based on:E1 Switchgear energetic phase HEAF zone of influence does not cause a loss of DS Bus power or E2 BusPer NUREG/CR-6850 Appendix M and FAQ 06-0017, 480V HEAFs have not caused damage beyond the switchgear itselfFAQ 06-0017 limits 480V HEAFs to feeder breakersThe 480V HEAF ZOI is smaller than the NUREG/CR-6850 Appendix M for medium voltage switchgear Significance Determination Recovery CreditFull recovery credit (defined as 92.5%) should be appliedDSP-002 establishes initial success for SG feed with SDAFWMaintaining feed leads to successNo diagnosis required by the operatorStress -high Complexity -nominal Training -nominalProcedures -availableIndications -availableExpansive time is availableTech Support Center provides oversight Fan Belt replacement is straightforwardRobinson ICCDP evaluation is approximately 6.5E-07 Causes and Corrective ActionsTom CosgroveRobinson Plant Manager Evaluation Results: CausesRoot Cause -A time based preventative maintenance basis prescribing fan belt replacement did not exist Primary Contributing CausesBelt Procedure steps not prescriptiveDegraded motor sheave conditionContributing CausesDid not exhibit the behaviors needed to achieve high standards of reliability and availability of the DSDGBelt guard design precluded routine monitoringLack of maintenance rigor in use of vendor information (used qualitative vice quantitative inspection techniques)

Corrective Actions: Immediate / InterimImmediate Actions TakenReplaced the radiator fan beltsModified the radiator fan belt guardInterim Actions TakenImplemented additional short term motor, fan and bel t monitoring actions Conducted leadership and maintenance briefsCompleted system expectation sessions with maintenan ce, engineering, work management, operations and station leadership Corrective Actions: To Address CausesCorrective Actions to Preclude RecurrenceImplemented a time based DSDG belt replacement frequ ency of 2 yearsOther Key Corrective Actions to Address CausesReplaced sheaves and modified the DSDG fan motor mountingRevised maintenance procedures to include quantitative sheave exam, belt inspection, and tensioning criteria (Programmatic)Integrated DSDG into the station's Reliability Impro vement Plan (Organizational)Conduct "Training for Performance Improvement" (Includes Continuing and Initial Training)

Corrective Actions: Extent of ConditionEmergency Diesel Generators (EDGs) A&B supply/exhaust fan belts replacedPreventive Maintenance (PM) for EDGs supply/exhaust fan time based replacementPM for time based replacement -Engine Driven Fire Pump/alternatorSecurity DG radiator fan and alternator drive belts replacedPM for replacement of Instrument Air compressors A/B drive belts on 4 year frequency Corrective Actions: Extent of CauseIdentify new PMs for beltsFlex equipment 4th Train AFW DGDeep Well DGIdentify new PMs for elastomericsAFW Service Water Fire Protection CVCS Expand scope of systems if 4 or more new PMs are nee dedSingle Failure study -DSDG and support systems New Sheaves and Mounting System for DSDG Radiator Fan Radiator Fan Belt Guard with New View Port./'

Regulatory PerspectivesMike GloverDirector -Site Operations Regulatory PerspectivesApparent violation of 10 CFR 50.63 (Blackout Rule) for failure to perform adequate preventative maintenance on the Dedicated shutdown Diesel Generator (DSDG) cooling system.Robinson agrees with the Apparent Violation from the aspect that no time based replacement activity was in place for the DSDG radiator fan beltsCorrective Actions to restore compliance were completed on October 3, 2012Comprehensive actions have been taken to prevent rec urrenceOther corrective actions are taken or plannedIn summary, despite the temporary loss of the DSDG, the combination of the above along with the other actions described in this presentation serve to ensure mitigation necessary to prevent core damageDuke Energy's analysis concludes that the Finding is of very low safety significance Closing RemarksPreston GillespieSenior Vice President, Nuclear Operations