05000318/LER-2022-003, Pressurizer Safety Valve As-Found Settings (Low) Outside Technical Specification Limits Due to Setpoint Drift
| ML22325A332 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/21/2022 |
| From: | Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML22325A330 | List: |
| References | |
| LER 2022-003-00 | |
| Download: ML22325A332 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| 3182022003R00 - NRC Website | |
text
Abstract
OnSeptember21,2022,duringtestingattheoffsitetestingfacility,theasfoundliftsettingforthepressurizersafety valve(PSV)previouslyinstalledinUnit2atthe2RV200locationwasmeasuredlowoutsidetheTechnicalSpecification allowablevalue.ThevalvehadbeeninstalledinMarch2021duringtheUnit2refuelingoutage.Leakagepastthe valveseatwasinitiallyidentifiedinJuly2021andtookastepchangeinApril2022.Thisleakagewasformally monitoredbythesiteuntiltheplannedmaintenanceoutageinSeptember2022wherethe2RV200PSVwasreplaced.
The2RV200PSVwasdisassembledandinspectedatanoffsitefacilitywhereunsatisfactoryinternalcomponentswere identified,includingthestainlesssteelspindlerunoutmeasurementandthebellowshavingavisiblybulgednose.
(See Page 3 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Page 5 of 5 F.CORRECTIVEACTIONS
AsparevalvewithanInconelspindlewasinstalledduringtheSeptember2022Unit2maintenanceoutage.
ApplicablesiteprocedureshavebeenrevisedtoreincorporatetherequirementforperformingthePressurizersoak andgradualRCSpressurizationtoNOP.
ThePSVtestprocedureisbeingrevisedtofirmlylimitthenumberofliftsallowedperthetestprocedurewhen initiallyestablishingthevalveliftsetpoints.
G.PREVIOUSOCCURRENCES
AreviewofCalvertCliffseventsoverthepastseveralyearswasperformed.ThesitehashadseveralinstancesofPSV setpointtesting(lowandhigh)abnormalities.Asnotedbelow,theapparentcausesforpreviousfailuresweredueto differentissues.ThefollowingLERswereidentifiedfromthisreview:
LER318/2011002Setpoint(high)failurecauseidentifiedasgreaterthanexpectedsetpointvariation,License AmendmentRequestsubmittedtoexpandtheallowablesetpointrange.
LER318/2013002Setpoint(high)failurecauseidentifiedasinadequatemargin,subsequentapprovalofLicense AmendmentRequesttoincreaseallowedliftsettingrangeoccurredonDecember30,2015.
LER317/2014003Setpoint(low)failureontwoseparatevalves-identifiedastheinternalliftspringassembliesofa specificmanufacturerlotfailedtoholdPSVsetpressure.
LER318/2017001Setpoint(low)failurecauseidentifiedassetpointdriftinunexpecteddirection.
LER317/201800101Setpoint(low)failurecauseidentifiedduetodamagedinternals.
H.COMPONENTFAILUREDATA
Component
FUNCTIONID
SYSTEMID
PressurizerSafetyValve
RV
TheUnit2pressurizersafetyvalvemanufacturerisDresserConsolidated,Inc.