ML120100205

D-11-2 Presentation for Meeting on January 11, 2012, at 1:30 Pm

ML120100205
Person / Time
Site:	Palisades
Issue date:	01/11/2012
From:	Entergy Nuclear Operations
To:	NRC/RGN-III
References
Download: ML120100205 (39)

Text

ENTERGY NUCLEARNRC Regulatory ConferenceNRC Regulatory ConferencePalisades Nuclear PlantPalisades Nuclear PlantJanuary 11, 2012January 11, 2012Reactor Trip DuringReactor Trip During Panel ED Panel ED--11 11--2 Maintenance2 MaintenanceEntergy Nuclear Operations ENTERGY NUCLEAR 22 Tony Vitale Site Vice PresidentEntergy -Palisades ENTERGY NUCLEAR 333AgendaAgendaIntroductionTony VitaleObjectivesTony VitaleApparent ViolationTony VitaleCausesDavid HamiltonKey Corrective ActionsDavid HamiltonTimelineDavid HamiltonSignificanceFrank YanikConclusionsTony Vitale ENTERGY NUCLEAR 444ObjectivesObjectivesDiscuss the apparent violation andEntergy's acceptanceReview the causal analysis and corrective actions taken and plannedDiscuss the background and event timelineProvide additional insights into the safety significance of the event ENTERGY NUCLEAR 555Apparent ViolationApparent ViolationEntergy concurs with the apparent violationEntergy has additional information forconsideration regarding the safety significance of the finding ENTERGY NUCLEAR 6 Palisades Performance Recovery Plan Palisades Performance Recovery PlanPlan Areas-Leadership Effectiveness-Safety Culture-Corrective Action Program-Equipment Reliability-Refueling Outages-Communication Plan ENTERGY NUCLEAR 7 Palisades Performance Recovery Plan Palisades Performance Recovery PlanLeadership Effectiveness

-Problem Statement-Leaders are not sufficientlyengaged and intrusive to identify and correctbehavior and performance gaps at all levels of theorganization.

-Vision Statement-Leaders are engaged andintrusive to identify and correct behavior andperformance gaps. Leaders routinely spend time inthe field with eyes on the problems to provideoversight and reinforce standards. Leaderscontinually reinforce the principles for a strongnuclear safety culture.

ENTERGY NUCLEAR 8 Palisades Performance Recovery Plan Palisades Performance Recovery PlanSafety Culture

-Problem Statement -Degradation of safetyculture principles has led to siteperformance deficiencies

-Vision Statement-All station personnelexhibit proper risk sensitivity andawareness. Mitigating strategies areconsistently implemented.

ENTERGY NUCLEAR 9 Palisades Performance Recovery Plan Palisades Performance Recovery PlanCorrective Action Program-Problem Statement-The Corrective ActionProgram is not always valued or effectivelyused by Palisades leadership and personnelto identify, investigate, and correct problemsin a timely manner to improve performance.-Vision Statement-Success in theimplementation of a strong corrective actionprogram is evidenced by Palisadespersonnel identifying and correcting issuesat low levels.

ENTERGY NUCLEAR 10 Palisades Performance Recovery Plan Palisades Performance Recovery PlanEquipment Reliability-Problem Statement-Critical equipment failureshave lead to plant derates, forced outages,schedule perturbations, increased radiological dose,unplanned limiting conditions for operation, reworkand failed post maintenance tests. Scheduleadherence and stability are improved, thus limitingrisk to operation.-Vision Statement-Success in equipment reliabilityis evidenced by Palisades achieving top decileperformance in unit capability factor (currently>94.38%), low rework rates, lower collectiveradiation exposure and no unplanned AOTs.

ENTERGY NUCLEAR 11 Palisades Performance Recovery Plan Palisades Performance Recovery PlanRefueling Outages

-Problem Statement-Ownership of the outage preparation andexecution process must be improved to support station operation andmaintenance. Work must be scheduled where appropriate, plannedeffectively and completed when scheduled.

-Vision Statement-The objective of this Recovery Plan is to provideimprovement in the implementation of the outage managementprocess at Palisades by the following:Affirming and continually reinforcing ownership of the outage workmanagement process by all Palisades employees and contractors throughfrequent communication, effective preparatory meetings and management interaction.Establishing effective outage preparation meetings so that highaccountability and team work is evident in preparations.Displaying effective performance indicators to drive accountability down tothe supervisor/worker level inside and outside of the Planning, Scheduling &Outage department.Developing a long range schedule of coordinated self evaluation,peerevaluation and nuclear oversight to assess the adequacy of outagereadiness, its implementation at all levels, and potential areasforimprovement.

ENTERGY NUCLEAR 12 Palisades Performance Recovery Plan Palisades Performance Recovery PlanCommunication Plan

-Problem Statement-Important to ensure wecommunicate effectively to our employeesand have them engaged in our recovery.-Vision Statement-Palisades employees arewell informed of the causes, contributorsand corrective actions of our currentsituation. Additionally, the employees areengaged and empowered in the execution ofthe plan. Employee ownership is evident.

ENTERGY NUCLEAR 13 13 David HamiltonGeneral Manager Plant OperationsEntergy -Palisades ENTERGY NUCLEAR 14 Event ResponsePalisades Root Cause Evaluation Team-Human performance error review and event timeline-Focused on both direct technical cause andorganization and programmatic aspectsCorporate Event Response Team (CERT)-Independently reviewed event causes and contributors-Focused on organizational and programmatic aspects ENTERGY NUCLEAR 15 15 15Causal AnalysisCausal AnalysisRoot Cause -OrganizationalSenior leaders have not established a sufficientlysensitive culture of risk recognition andmanagement. This resulted in the plant'smanagers, supervisors and workers notrecognizing, accounting for, or preparing for, theindustrial safety risk and plant operational nuclearrisk involved with the panel ED-11-2 breakerinspection and replacement maintenance.

ENTERGY NUCLEAR 16 16 16Causal AnalysisCausal AnalysisContributing Cause 1 -TechnicalBreaker coordination for the 125 VDC system left train was insufficient toprevent a reactor trip under the short circuit conditions experienced duringED-11-2 maintenance on 09/25/11Contributing Cause 2 -OrganizationalWork orders used for removal and inspection of breakers 72-119, 72-120, 72-121 and 72-123 did not include details appropriate for maintenance onenergized, high critical electrical equipment with the plant on lineContributing Cause 3 -Human PerformanceOversight by managers and supervisors did not result in identification andcorrection of the human performance errors and weaknesses in theworkinvolving the inspection and replacement of breakers in the ED-11-2 panelContributing Cause 4 -Human PerformanceManagers, supervisors and workers did not consistently follow approvedprocedures for job preparation, job execution and risk management ENTERGY NUCLEAR 17 17 17Corrective ActionsCorrective ActionsKey Technical Actions -short termactions to prevent recurrenceTemporary modification was installed to raise themagnetic trip settings of breakers 72-01 and 72-02 to the highest level, coupled with removingcircuits capable of exceeding trip currentDamaged bus connectors and suspect breakersin Panel ED-11-2 were replaced ENTERGY NUCLEAR 18 18 18Corrective ActionsCorrective ActionsKey Organizational ActionsEntergy Standards for procedure compliance,accountability, and intolerable behaviorsreinforced via face to face communications fromthe COO through Individual Contributor LevelsManagement observation program structuredwith guidance to provide specific oversight andfeedback on safety culture behaviors, riskrecognition and mitigation, procedure adherence,and standards reinforcement.Initiated third party safety culture assessment ENTERGY NUCLEAR 19 19 19Corrective ActionsCorrective Actions Key Human Performance ActionsEnsure compliance with Entergy risk management proceduresIssued guidance for work on all energizedelectrical circuits to ensure appropriate nuclear safetyWork order quality improvements ENTERGY NUCLEAR 20 20 20Corrective ActionsCorrective ActionsKey Work Management ActionsAt T-5 critical evolutions meeting and T-2technical rigor meeting, validate actions andmitigation of risk associated with work activities-SVP challenge of risk assessment-Fleet challenge up through COO of risk assessmentClear identification of risk activities and riskmitigators in work schedules, and daily planning meetings ENTERGY NUCLEAR 21Palisades Recovery Plan and Fleet ActionsDefined intolerable leader behaviorsDefined intolerable worker behaviorsReview of risk activities cascaded through siteand corporate managementStructured paired management observation andintervention of worker and leader behaviors-Fleet observation and intervention-Independent observation and interventionLeadership assessment of organizational andsafety culture competencies.

ENTERGY NUCLEAR 22Importance of TimelineExtremely important to our significance determination tounderstand the timeline with accuracy-Impact on human performance assumptions-Impact on operator capability assumptions-Assumed plant conditions during various points in the event in the PRAExtensive validation effort to ensure accuracy for bothPRA and root cause evaluation ENTERGY NUCLEAR 23 23Timeline -Event9/25/11 (Sun): Initial conditions (prior to event)9/25/11 15:06: Equipment actuation9/25/11 15:06: EOP-1 Post-Trip entered9/25/11 15:17: Generator breakers opened viarelay jumper9/25/11 15:27: EOP-9 Functional Recovery entered*9/25/11 15:28: Pressurizer level exceeded 62.8%*9/25/11 15:31: High S/G E-50A level @ 90%*9/25/11 15:31: ONP-2.3 Loss of DC Power entered*Denotes events critical to PRA discussion ENTERGY NUCLEAR 24 24Timeline -Event9/25/11 15:37: ONP 24.1 and ONP 24.3 Loss of PreferredAC Bus Y-10 and Y-30 entered*9/25/11 15:37: High PCS pressure (2200 psia) and highpressurizer level; B channel controllersplaced in service9/25/11 15:42: CVCS letdown orifice stop valves closed*9/25/11 15:44: P-8C AFW flow to S/G E-50A isolated9/25/11 15:49: Power restored to 2400V Bus 1E EA-13*9/25/11 15:57: Left channel SIAS; SI throttled*9/25/11 15:57: DC busses ED-10L & ED-10R, andpreferred AC bus EY-30 reenergized*Denotes events critical to PRA discussion ENTERGY NUCLEAR 25 25Timeline -Event9/25/11 16:02: Power restored to bus 1E EA-13*9/25/11 16:03: Steam supply to AFW pump P-8B isolated*9/25/11 16:09: AFW flow to S/G E-50B isolated*9/25/11 16:15: Pressurizer level peaks at 101.5%*9/25/11 16:39: P-8C AFW flow to S/G E-50B restored*9/25/11 16:46: Preferred AC bus EY-10 reenergized;ADVs available*9/25/11 18:52: AFW pump P-8B availability restored*9/25/11 19:33: Battery charger #3 ED-17 placed in service*Denotes events critical to PRA discussion ENTERGY NUCLEAR 26 26 Frank YanikPRA EngineerEntergy -Palisades ENTERGY NUCLEAR 27 27 27 Significance Determination Significance DeterminationOverview and conclusionsKey inputs and assumptionsImpact on event risk characterization ENTERGY NUCLEAR 28 28 Significance Determination Significance Determination Preface PrefaceEvent TimelineRigorous timeline validationData context important 28 ENTERGY NUCLEAR 29 29 Significance Determination Significance DeterminationEntergy ConclusionsEntergy ConclusionsCCDP is4.3E-6Dominant sequences involve failure to recover lost trainof DC power sourceContributing sequences involve failure to securecharging pumps prior to lifting PZR SRVsStuck open PZR SRV LOCA can be mitigated withcharging system (2 of 3 pumps and SIRWT suctionsource) and AFW 29 ENTERGY NUCLEAR 30 30 Significance Determination Significance Determination Entergy Conclusions (con Entergy Conclusions (con

t)t)Isolation of turbine driven auxiliary feedwater pump P-8Bto avoid overfill not a significant risk contributorMotor driven auxiliary feedwater pump P-8A remainedavailable from control room throughout eventRestoration of P-8B simple, well-trained task,especially given EOP Supplement 19 steps alreadyperformed 30 ENTERGY NUCLEAR 31 31 31 Entergy Perspectives on Entergy Perspectives onKey Inputs and AssumptionsKey Inputs and AssumptionsProbability of recovery of DC powerProbability of preventing challenge (lift) ofpressurizer (PZR) safety relief valve (SRV)Probability of stuck open PZR SRVAvailability of AFW Pump P-8ANormal maintenance unavailabilities ENTERGY NUCLEAR 32 32 Probability of DC Power Recovery Probability of DC Power RecoveryTime available to recover DC power is at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />(no AFW)Actions to restore power are simple and straightforwardonce the fault condition is clearedTwo options are available to restore DC power:Restoration of the connection of the DC bussegments to the battery (HEP = 0.1)Alignment of the alternate charger to the DC bussegments (HEP = 0.1)Total Effective HEP 0.01 (0.1

• 0.1) 32 ENTERGY NUCLEAR 33 33 33PZR SRV Challenge ProbabilityPZR SRV Challenge ProbabilityComplexity of action and time available greatlyimpact probability (and overall results)For Entergy modelAction is simple trip of operating charging pumpsTime available based on maximum charging flow forloss of DC eventTime available allows for recovery of failed attemptsFor NRC evaluationAction is "control pressurizer level"-may be viewedas more complexTime available about equal to time required -may bebased on 133 gpm charging flow ENTERGY NUCLEAR 34PZR SRV Challenge Probability HEP TimelineTime available to diagnose/execute action -62 mins

-Operators determine in-service channel A to PZR levelcontrol is de-energized and change to channel B -31minutes (1537)

-Time to operators confirm boration requirements met -51minutes (1557)

-Operators terminated charging flow -51 minutes (1557)11 minutes remained available to complete theaction to prevent a challenge to PZR safeties ENTERGY NUCLEAR 35 35 35Stuck Open PZR SRV ProbabilityStuck Open PZR SRV ProbabilityPalisades valves tested for steam, transition & water relief (part ofTMI Action Plan)Test conditions based on consideration of PWR FSAR transientsand extended high pressure liquid injection eventsAll tests found satisfactory operationFor Entergy modelPalisades-specific SRV qualification testing supports use of generic failure ratesFor NRC evaluationGeneric bounding SRV failure probability used ENTERGY NUCLEAR 36 36 36AFW PAFW P--8A Availability8A AvailabilityP-8A remained available on manual start from thecontrol room (or locally) throughout eventLoss of DC power resulted in loss of power to pump controlschemeHowever, without DC panel ED-11-1, a low suction pressure tripsignal cannot trip the pumpED-11A remained available; this provided DC power to theswitchgear supplying AC to P-8AAssuming P-8A unavailable without restoration increasesimportance of restoration of P-8B ENTERGY NUCLEAR 37 37 37ConclusionConclusionBased on investigation and evaluation of theevent, Entergy determined that the CCDP is 4.3E-6a.Failure to recover DC power is ~ 74% of CCDPb.Failure to control pressurizer level is ~ 16%

of CCDP ENTERGY NUCLEAR 38 38 Tony Vitale Site Vice PresidentEntergy -Palisades ENTERGY NUCLEAR 39 39 39 Summary SummaryEntergy concurs with the violationA thorough review of the event wasperformed to identify all related causesEntergy has developed effectivecorrective actions for root andcontributing causesFleet engagementWelcome the opportunity for future updates with Staff