ML16285A325

ROP PI Frequently Asked Questions (Faqs): 14-02

ML16285A325
Person / Time
Site:	Fort Calhoun
Issue date:	10/12/2016
From:	Mary Anderson NRC/NRR/DIRS/IPAB
To:
Anderson M,NRR/DIRS,301-415-8744
References
Download: ML16285A325 (7)

Text

NEI9902FAQ1402 FortCalhounMSPI

Page1of5 Revised09/8/2014 Plant:FortCalhounNuclearStation

DateofEvent: 12/18/2013(ReactorCritical)

SubmittalDate:05/14/2014

LicenseeContact: ErickMatzke Tel/Email: 4025336855ematzke@oppd.com

NRCContact:LouisCruz Tel/Email: 3014153982louis.cruz@nrc.gov

PerformanceIndicator:MS06 MitigatingSystemPerformanceIndex(EmergencyACPowerSystems)

MS07MitigatingSystemPerformanceIndex(HighPressureInjectionSystems)

MS08MitigatingSystemPerformanceIndex(HeatRemovalSystems)

MS09MitigatingSystemPerformanceIndex(ResidualHeatRemovalSystems)

MS10MitigatingSystemPerformanceIndex(CoolingWaterSystems)

SiteSpecificFAQ(AppendixD)?Yes FAQrequestedtobecomeeffective: Whenapproved.

QuestionSection

NEI9902,Revision07,Guidanceneedinginterpretationand/oradditionalinformation:

TheMSPISection(startingonpage32)doesnotprovideguidanceontheprocessinvolvedin reportingperformanceindicatordataforlicenseesthathavestartedupafterhavingbeeninashutdown conditionforanextendedperiodoftime.MSPIvaluesaresensitivetounavailabilityhourswhenthe criticalhoursforaunitarelow,asisthecasewithaplantstartingupafteranextendedshutdown.In this,MSPImaynotbeavalidindicationofperformanceandshouldbeconsiderednotvaliduntil sufficientcriticalhoursareaccrued.

ThedraftNRCStaffWhitePaperonPerformanceIndicatorValidityduringExtendedShutdownand SubsequentStartup,lastdiscussedattheApril2014ROPWorkingGroupmeetingnotes:

Forplantsthatareinextendedshutdownconditions,theMSPIdataelementscontinuetobereported.

Oncethelicenseeanticipatesthatashutdownwillenteranextendedperiod(sixmonths),aFAQshall besubmittedfortheROPWorkingGrouptodetermineMSPIvalidity.Thelicenseeshallsubmitan additionalFAQtoestablishMSPIvalidityuponsubsequentstartup.

TimelineofsignificanteventsforFortCalhounStation:

April,2011-FortCalhounNuclearStationshutdown:26RefuelingOutage.

June6,2011-DeclaredaNotificationofUnusualEvent-Risingfloodwaters August29,2011ExitedNotificationofUnusualEvent-RiverLevel10036andlowering June7,2011-1B4ALoadCenterfire December,2011-FCSenteredInspectionManualChapter0350.

December21,2013-Breakersclosedandextendedoutageended.

NEI9902FAQ1402 FortCalhounMSPI

Page2of5 Revised09/8/2014 NRCResidentComments

ResidentsInspectorhadnocomments.

LicenseePosition

FCSwillcontinuemonitoringMSPIandreportingdataelementsonaquarterlybasis.The performanceindicatorshallremainN/Auntilreporteddataisexpectedtobeamoreaccurate reflectionofcurrentplantperformance.

Thelackofcriticalhoursforthepast12quartershasandwillcontinuetoskewthe performanceindicatorsvalidity.Ascriticalhoursareaccrued,performanceandpredictability becomesincreasinglyrepresentativeofactualperformanceofthestation.Asoneofthebasic premisesofMSPIisthatasinglefailureshouldnotresultinanadverseindicator,thefollowing criteriawereusedbyFt.CalhounStationtodeterminewhentherewillbesufficientcritical hourstoavoidafalsepositiveindicator:

1. Thereshouldbeatleast4quartersofdatafollowingthestartupfromthe extendedoutage,and

2. TheMSPIvalueshouldbeabletotoleratetheworsesinglefailureand unavailabilityequaltoafullLCOCompletiontimeandremainGreen(1.0E 6/yr)followingstartupfromtheextendedoutage.

AplantspecificPWROwnersGroupWhatIftoolwasusedtopredictfutureMSPIvalues usingexpectedplantdata(UnavailabilityandUnreliability).

ThechartsbelowillustratestheimpactfortheEACandRHRsystemsfromhavingafailureand associatedunavailabilityinthe4thquarter2014andtheimpactonMSPIasadditionalcritical hoursareaccrued:

NEI9902FAQ1402 FortCalhounMSPI

Page3of5 Revised09/8/2014

EAC Q12014 Q22014 Q32014 Q42014 Q12015 MSPI 2.4E08 2.7E07 3.0E07 1.2E06 9.2E07 UAI 9.50E09 2.86E07 3.31E07 7.11E07 6.92E07 URI 1.49E08 1.31E08 3.18E08 4.66E07 2.32E07

%Baseline CritHrs 9.7%

18.7%

27.8%

35.6%

45.8%

Q12015MSPIdecreasereflectsaFeb2012failuredroppingoutofthe3yearmonitoringperiod.

BothDG2YearOverhauls(103hourseach)areincludedin2014estimate.

PastMSPIvaluesreflectoriginalestimateforobservedperiod.

2.00E07 0.00E+00 2.00E07 4.00E07 6.00E07 8.00E07 1.00E06 1.20E06 1.40E06 Q12014 Q22014 Q32014 Q42014 Q12015 MSPI UAI URI AssumedFailureand appliedfullLCO EAC

NEI9902FAQ1402 FortCalhounMSPI

Page4of5 Revised09/8/2014

RHR Q12014 Q22014 Q32014 Q42014 Q12015 Q21015 Q32015 Q42015 Q12016 MSPI 1.7E07 1.5E07 1.5E07 1.9E06 1.7E06 1.4E06 1.2E06 1.1E06 9.9E07 UAI 1.92E07 1.37E07 1.37E07 1.51E06 1.35E06 1.08E06 8.93E07 7.66E07 6.60E07 URI 1.73E08 1.05E08 9.47E09 3.52E07 3.24E07 3.24E07 3.25E07 3.18E07 3.35E07

%Baseline CritHrs 9.7%

18.7%

27.8%

35.6%

45.8%

50.2%

59.4%

68.5%

77.5%

Estimatedplannedunavailabilityhoursforeachquarter:7hours.

RFO27isscheduledfor45daysduringQ2_2015.

2.00E07 3.00E07 8.00E07 1.30E06 1.80E06 2.30E06 Q12014 Q22014 Q32014 Q42014 Q12015 Q21015 Q32015 Q42015 Q12016 MSPI UAI URI Assumed Failure RHR

NEI9902FAQ1402 FortCalhounMSPI

Page5of5 PotentiallyrelevantexistingFAQnumbers:None

ResponseSection

Basedontheresultsofthissensitivitystudy,thefollowingtableidentifieswheneachMSPI shouldbeconsideredvalid:

MSPISystem Effective Date LimitingCriteria MS06-EmergencyAC Power 1stquarter 2015 SingleFailureplusassociatedunplanned unavailability(fullLCO)yieldswhite indicatorin4thquarter2014butgreenin 1stquarter2015 MS07-High PressureInjection System 4thquarter 2014 4quartersdata MS08-Heat RemovalSystem 4thquarter 2014 4quartersdata MS09-Residual HeatRemoval System 1stquarter 2016 SingleFailureplusassociatedunplanned unavailability(fullLCO)yieldswhite indicatorin4thquarter2015butgreenin 1stquarter2016 MS10-Cooling WaterSystem 4thquarter 2014 4quartersdata

NRCResponse

FAQ 14-02: FCS MSPI Validity NRC Response According to the Simulation of MSPI Indicator Reaction to Plant in Long Term Shutdown and Initial Startup Page white paper discussed in the ROP Working Group (The last documented version of this white paper is available through Agencywide Document Access and Management System (ADAMS)

Accession No. ML13079A728), the ROP Task Force recommended and the NRC staff agreed with the following:

ROP Task Force Recommendations The data from this study (Figure 1) shows that MSPI is very reactive when critical hours are low. This indicates that these situations should be treated on a case-by-case basis. Fortunately, these situations have been uncommon over the life of the ROP, so that it is practical to consider a case-by-case approach.

As a starting point for these case-by-case discussions, the ROP Task Force recommends the following decision rules for the display of MSPI on the NRC web page:

• Gray out MSPI when a unit has been shut down for six months.

o On plant startup, if the calculated MSPI is greater than 1.0E-6 (White) for the quarter prior to startup, MSPI will remain grayed out until 12 months of operation have accumulated after startup.

o On plant startup, if the calculated MSPI is less than or equal to 1.0E-6 (Green) for the quarter prior to startup, MSPI will remain grayed out until there is a total of 12 months of operation in the 3-year monitoring period.

• Gray out MSPI for the startup of new plants until 12 months of operation have accumulated Given that FCS restarted on December 2013, the quarter prior to startup is 3Q-2013. All MSPI values for FCS were green in 3Q-2013. Therefore, the starting point in treating the validity of the MSPI indicators is that: MSPI will remain grayed out until there is a total of 12 months of operation in the 3-year monitoring period. For this particular case, 4Q-2014 represents the time-frame at which a total of 12 months of operation have been accumulated.

In this FAQ, the licensee, FCS, proposes that the High Pressure Safety Injection (HPSI) system MSPI, Heat Removal System (HRS) MSPI, and Cooling Water System (CWS) MSPI become valid on the 4th quarter of 2014. However, FCS proposes that the Emergency AC (EAC) power and Residual Heat Removal (RHR) system MSPI indicators become valid on the 1st quarter of 2015 and 1st quarter of 2016, respectively.

FCS predicted future MSPI values using a Pressurized Water Reactor Owners Group What-if tool and expected plant data for unavailability and unreliability. These estimated MSPI values defined the licensees proposal of the respective effective dates for each MSPI indicator to become valid. The NRC staff agrees with the proposal for the HPSI, HRS, and CWS MSPIs to become valid on 4Q2014, and for the EAC MSPI to become valid on 1Q2015. However, the NRC staff does not agree with the proposal for the RHR MSPI to become valid on 1Q2016.

The staff recognizes that the approach to maintain the RHR MSPI indicator invalid before 9 quarters of operational data have been accrued proactively prevents the indicator from resulting in a false positive due to accrued unplanned unavailability. However, various factors such as increase in inspection resources, aggregation of various inputs to the indicator, alignment with previously established positions, and external stakeholder communications should also be taken into consideration when defining an effective date for the indicator to become valid.

Having the RHR MSPI invalid before 9 quarters of data have been accrued will increase inspection resources. While a baseline inspection approach would be applied to all other systems covered by MSPIs, additional inspection hours would have to be implemented to gain performance insights on the RHR system.

Having the RHR MSPI invalid before 9 quarters of data have been accrued limits the indicator from providing insights on RHR performance based on the estimated outcome of accrued unplanned unavailability. It does not allow the indicator to provide insights on RHR performance that might result from any other failures and/or unavailability observed under this indicator.

The approach of having the RHR MSPI invalid before 9 quarters of data have been accrued results in a significantly different treatment from that used for the other MSPIs. It also diverges noticeably from the starting point for evaluation of such situation that was discussed through white papers in the ROP WG (ADAMS Accession No. ML13079A728), and the initial characterization of this FAQ. Such divergent approach can impact the overarching ROP goals of understandability and predictability.

Having the RHR MSPI invalid before 9 quarters of data have been accrued while all other MSPI indicators are treated as valid performance indicators can present communication challenges to external stakeholders. Such unique approach would impact the clarity of the performance indicator program.

Since historical data on RHR unplanned unavailability was not considered, accounting for the Technical Specifications (TS) Allowed Outage Time (AOT) (i.e., 7 days) could be a highly conservative estimate. If an indicator is really invalid for 9 of a total of 12 quarters (75%), what other types of implications can be inferred? Although TS SSCs in general make-up the list of monitored components in MSPI, the AOTs, surveillance frequencies, etc. do not necessarily correlate with risk importance (i.e., maybe TS AOTs is not a good input to use for a risk-based calculation).

The NRC staff concludes that: (1) the HPSI, HRS, and CWS MSPIs should become valid on 4Q2014, and (2) the EAC and RHR MSPIs should bercome valid on 1Q2015.