ML19011A152

Clarification of the Requirements for Reactor Pressure Vessel Upper Head Bare Metal Visual Examinations - January 2019 Industry/Nrc Nondestructive Examinations Public Meeting

ML19011A152
Person / Time
Issue date:	01/11/2019
From:	Stephen Cumblidge NRC/NRR/DMLR/MPHB
To:
Rezai A, NRR-DMLR 415-1328
References
RIS-18-006
Download: ML19011A152 (9)

See also: RIS 2018-06

Text

NRCREGULATORYISSUESUMMARY201806

CLARIFICATIONOFTHEREQUIREMENTSFORREACTOR

PRESSUREVESSELUPPER

HEADBAREMETALVISUALEXAMINATIONS

StephenCumblidge

NRC/IndustryNDETechnical

InformationExchangeMeeting

January1517,2019

RISonUpperHeadInspections

Asdiscussedinthe2017meeting,theNRChas

publishedaRISclarifyingupperheadinspection

requirements

ThegoaloftheRISistoreiteratethattheVE

examinationacceptancecriteriaarenotdependent

onthematerialusedfortheupperhead

TheNRChasbeenenforcingN7294asdescribed

intheRISandtheRISdoesnotdescribenew

requirements

2

BMVRelevantConditions

FromN7294

RelevantconditionsforthepurposesoftheVE

shallincludeareasofcorrosion,boricaciddeposits,

discoloration,andotherevidenceofnozzle

leakage

Componentswithrelevantconditionsrequire

furtherevaluation.Thisevaluationshallinclude

determinationofthesourceoftheleakageand

correctionofthesourceofleakageinaccordance

with3142.3.

IndicationsofPossibleNozzleLeakage

Anozzlewithrelevantconditionsindicativeof

possible nozzleleakageshallbeacceptablefor

continuedserviceiftheresultsofsupplemental

examinations[3200(b)]meettherequirementsof

3130.

Acomponentwithrelevantconditionsindicativeof

possible nozzleleakageshallbeacceptablefor

continuedserviceifarepair/replacementactivity

correctsthedefectinaccordancewithIWA4000.

CommentsandCommentResolution

TheNRCreceived10CommentsontheRIS

Severalwereclarifications TheNRCagreedor

partiallyagreedwithfivecomments

TheNRCdisagreedwithfivecomments

Thecommentsandrecentproposedalternatives

toN7291pointtopossibleusefulcodeactions

5

LeaksFromAbovearenotRelevant

Boricaciddepositsfromothersourcesarenot

consideredrelevantindicationsunderthescope

ofN7294.

NRC Paragraph3141(c)statesRelevant

conditionsforthepurposesoftheVEshall

includeevidenceofreactorcoolantleakage,

suchascorrosion,boricaciddeposits,and

discoloration.Leakagefromanysourcecan

producerelevantindications.

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N7294istooStrict

Ifitisveryclearthattheleakagehascomefromsourcesother

thanthenozzletherequirementsoftheCodeCaseN7294to

performasubsequentVEofpreviouslyobscuredsurfacesafter

cleaningpriortoreturntoserviceandagaininthesubsequent

refuelingoutageshouldbeadequate

WhiletheNRCmayagreethatthisapproachmaybeadequatein

somecases,itisnotcurrentlyincompliancewithN7294,and

wouldrequireaproposedalternativetobeused

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MoreGuidance

InlieuofthisRIS,theASMECodeCommittee

shouldbeengagedtoreviseCodeCaseN7294to

includeadditionaldetailsandtoclarifythetypeof

reactorhead(i.e.,replacementandmaterialsuchas

Alloy690).

NRCResponse Whilecleardefinitionsofcleaning

methodsinafuturerevisionofASMECodeCaseN

729wouldprovideimprovedguidanceforlicensees,

futurerevisionsofASMECodeCaseN729are

beyondthescopeoftheRIS

8

PathForward

TheNRCwouldreviewASMECodeActionstaken

toaddmoredetailtoN7294

DifferentcriteriaforPWSCCresistantand

PWSCCvulnerableheadsmaybeuseful

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