ML17171A187
| ML17171A187 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 06/14/2017 |
| From: | David Rudland Office of Nuclear Reactor Regulation |
| To: | |
| Setzer T | |
| References | |
| Download: ML17171A187 (5) | |
Text
BaffleFormerBolt InspectionsatIndianPoint Remarksby DavidL.Rudland Chief,VesselandInternalsIntegrityBranch OfficeofNuclearReactorRegulations U.S.NuclearRegulatoryCommission June14,2017 ML17171A187
BaffleformerAssembly Stainless steel bolts are 5/8 dia. x ~2 long Direct coolant flow through the core and provides lateral support to the core during a seismic event or loss-of-coolant accident (LOCA).
2
BaffleBoltInspection
- MRP227Acoversinspectionof reactorinternals
- MRPLetter2017011dictated interimguidance
- Ultrasonicinspectiontechnique
- Oneprobeperbolt,severalsensors andchannelsofdata
- Qualifiedfordetectiononly-go/no go
- Techniqueappearsconservative
- >50%ofboltsremovedretained someloadcarryingcapacity 3
RecentInspectionsatIndianPoint Plant EFPY@DateofUTExam DateofUTExam No.ofvisuallyfailed bolts No.ofboltswithUT indications No.ofboltsthatcould notbeUTexamined TotalNo.ofPotentially DegradedBolts No.ofBoltsReplaced No.BoltswithUT indicationsthatfailed uponremoval Indian
- Point, Unit2 31.1 Mar 2016 31 182 14 227 278 103 Indian
- Point, Unit3 28.6 Mar 2017 0
256 3
259 270 35 4
Total number of baffle-former bolts at IP2/3 is 832/unit
Conclusion
- Structuralintegrityofbaffleformerassemblyis maintainedatIndianPointdueto
- ReplacementofallboltswithUTindications
- Replacementofadditionalnondegradedboltsformarginand
- Subsequentboltinspectionsateveryrefuelingoutage
- NRCwillcontinuetoinspectboltexaminationresults throughthebaselineinspectionprogramatIndianPoint
- Morebroadly,theNRCstaffwillcontinuetoclosely monitorthebaffleformerboltoperatingexperienceand updatedinspectionguidancetoensurestructural integrity 5