ML17266A106

From kanterella
Revision as of 12:29, 29 June 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
Jump to navigation Jump to search
LER 79-030/01T-0:on 790921,discovered as-built Design Specs for Steam Generator Were Not Used by NSSS Vendor to Establish Instrument Span for Measuring Steam Generator Level.No Cause Given.Low Level Trip Setpoint Raised to 39%
ML17266A106
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 10/05/1979
From: SCHOPPMAN M A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17207A480 List:
References
LER-79-030-01T, LER-79-30-1T, NUDOCS 7910190346
Download: ML17266A106 (3)


Text

lfl ReportableOccurre335-79-30 LicenseeEventReportPagetwo'ADDITIONAL EVENTDESCRIPTION ANDPROBABLECONSEUENCESDuringanevaluation ofsteamgenerator levelsensinginst'rumentation conducted aspartofcompliance withNRCI&EBulletin79-21,itwasnotedthatthedesignspecifications ofthesteamgenerator hadbeenusedbytheNSSSvendortoestablish theinstrument spanformeasuring steamgenerator level.Inactuality, theas-builtdimensions shouldhavebeenemployedforthisdetermination.

TheFSARanalysisassumesareactortripduringalossoffeedwater accidenttooccurwhensteamgenerator waterleveldrops50inchesbelowthenormalwaterlevel.Asaresultofusingthedesign(insteadofas-built) steamgenerator dimensions, thelowleveltripsetpointof37Kisinerror(non-conservative) byapproximately 2X(4inches)incomparison withtheFSARcriteria.

TheFSARanalysisdoes,however,alsoassumeaninstrument errorof10inchesinanalyzing thelossoffeedwater accident.

Confirmation wasreceivedfromtheNSSSvendorthatpastoperation withthesetpointerrordidnothaveaneffectonthesafetyanalysisanddidnotaffectthehealthandsafetyofthepublic.Thiswasthefirstoccurrence ofthistype.ADDITIONAL CAUSEDESCRIPTION ANDCORRECTIVE ACTIONUseofwrongdimensions inestablishing thesteamgenerator levelsensinginstrument spanresultedina2Xerrorinthesteamgenerator lowleveltripsetpoint.

Immediate corrective actionwastoinstructthecontrolcenteroperators that,intheeventofalowsteamgenerator levelcondition, thereactorwastobemanuallytrippeduponreaching395level.AfterreceiptofNSSSconfirmation oftheplantstaff'sevaluation oftheproperinstrument span,theReactorProtective Systemsteamgenerator lowleveltripsetpointwasraisedto39$.