ML12243A435

Palo Verde Nuclear Generating Station, Units 1, 2 and 3 - 8/30/2012 Meeting RR 48 - Phased Array Ultrasonic Examination in Lieu of Radiography

ML12243A435
Person / Time
Site:	Palo Verde
Issue date:	08/30/2012
From:	Hansen D B Arizona Public Service Co
To:	Plant Licensing Branch IV
Gibson L K
References
Download: ML12243A435 (23)

Text

Re quest for Relief 48 Re quest for Relief 48 q

q Phased PhasedArray Ultrasonic Examination Array Ultrasonic Examination in lieu of

in lieu of Radiography RadiographyArionaPblicSericeCompan ArionaPblicSericeCompan Ari z ona P u blic Ser v ice Compan y Ari z ona P u blic Ser v ice Compan y Douglas HansenSr Consulting Engineer & LevelIII Agenda*Applicable codesRlifRt48S*R e li e f R eques t 48 S cope*Reasonfor Relief Request 48

• CodeCaseN-659-2*Code Case N-659-2 *Paragraph summary comparison (Attachment 2 of Relief Request)P/ThiVlidti

• P rocess/T ec h n i que V a lid a ti on*Samplecomparison graphics

• Conclusion Applicable Codes

• Construction Code ASME III

• 1974 Edition,Winter 1975 Addenda

• Repairs/Replacements

• ASMEXI2001Edition,2003AddendaASME XI 2001 Edition, 2003 Addenda Scope*ASME Class 2 piping circumferential butt welds

• Carbon steel base and weld metal

• Thickness >

0.337" *Diameters >

6" NPS*Geometry shall allow 100% coverage

• Weldand1/2"basemetaloneachside

• Weld and 1/2 base metal on each side*PVNGS Units 1, 2 and 3 forthe 3 rdinterval*Unit 1 thru 7-17-2018

• Unit 2 thru 3-17-2017

• Unit 3 thru 1-10-2018

Reason for Request

• Personnel-using Phased Array Ultrasonic Examination Technique (PAUT) reduces:

• Exposure risk

• Dose*Crew size*Outage-using PAUT:Reducestimeforresults

• Reduces time for results*Reduces impact to the schedule

• Allows adjacent work to proceed

• Reduces risk (errors) associated with

()starting/stopping/rescheduling critical activities

• Quality-using PAUT:

• Increasescriticalflawdetection Increases critical flaw detection*Provides flaw depths for repairs

• Recorded data for reviews and retention Code Case N-659-2 Inquiry: Under what conditions and limitations may an ultrasonic examination beusedinlieuofradiographywhereradiographyisrequiredbyNB

-5200, be used in lieu of radiography where radiography is required by NB 5200, NC-5200, ND-5200, WB-5200 or WC-5200, and substitution of ultrasonic examination would not otherwise be permitted?Reply: It is the opinion of the Committee that all welds may be examined using the ultrasonic (UT) method in lieu of the radiographic (RT) method, providedthatallofthefollowingrequirementsaremet:

provided that all of the following requirements are met:

N-659-2 (a) Examination Area

• Additional restrictions:

• 100% coverage (in all 4 directions)

• Weld ground flush

• Surfaceexamination(PTorMT)SfEA B Surface examination (PT or MT)S ur f ace Exam A-B1/2"1/2"AB CDPAUT Exam Volume A-B-C-D N-659-2 (b) Examination Procedure

• Additional restrictions:

• ASME Section V Article 4; 2001 Edition, 2003 Addenda

• PAUT with minimum of 40-70 degrees

• Volumescannedwith0degreeVolume scanned with 0 degree N 6592()PdDtti*Additional restrictions:

• Demonstrationforeachnominaldiameterandthickness N-659-2 (c)P roce d ure D emons t ra ti onDemonstration for each nominal diameter and thickness*Essential and non-essential requirements documented N-659-2 (d) Qualification Blocks

• Additional restrictions:

• For each nominal diameter and thickness 692()il*Additional restrictions:

• None;castandausteniticproductsarenotincluded N-6 5 9-2 (e) Mater i a l s*None; cast and austenitic products are not included N-659-2(f)ExaminationPlan

• Additional restrictions:

• None; an exam plan and sketch will be provided N-659-2 (f) Examination Plan N-659-2 (g) Acceptance Criteria

• Additional restrictions:

• ASME Section III; 2001 Edition, 2003 Addenda N-659-2 (h) Pre-Service Examinations

• Additional restrictions:

• Pre-Service Examinations (PSE) will be performed, when required, in addition to the proposed PAUT examinations

• Additionalrestrictions:N-659-2 (i& j) Acquisition Additional restrictions:

• None, examinations will be auto (encoded) and recorded

• Additional restrictions:

• Noneforacquisitionpersonnel;theywillbequalifiedand N-659-2 (k) Acquisition Personnel

• None , for acquisition personnel; they will be qualified and trained using the same demonstrated equipment N-659-2 (k) Analysis Personnel

• Additional restrictions:

• They will demonstrate their capability to detect and characterize flaws; will utilized data acquired with the demonstrated procedure; and:

• Detection*ASME XI Table VIII-S2-1

• Flawed grading units will be 1/4" longerthanactualflaw longer than actual flaw*Unflawed grading units will be a min of 1"*At least 2 of the flaws will meet N-659-2 (d) sizes

• Sizing*Flaws will be sized as being >

actual lengthFlillbl*Flaws w ill b e proper l y categorized as surface or

subsurface Additiltiti N-659-2 (l) ANII

• Additi ona l res t r i c ti ons:*None; review and acceptance of the ANII N 6592(m)Other Requirements

• Additional restrictions:

• None; other related requirements will be met N-659-2 (m) Other Requirements N-659-2 (n) Repairs

• Additional restrictions:

• None; flaws will be repaired and the weld re-examined

• Additional restrictions:

• None;theCasenumberwillberecorded N-659-2 (o) Code Case

• None; the Case number will be recorded Process/Technique Validation

• PVNGS developed a set of actual weld flawed specimens

• Flaws totaled over 60 for Carbon Steel

• Porosity*Incomplete fusion

• Incompletepenetration Incomplete penetration

• Slag*CrackingSihbdihd fi*S pec i mens have been ra diograp h e d f or compar i son*Specimens are being digital radiographedfor additional comparison Process/Technique Validation Process/Technique Validation RESULTS RESULTS *PAUT detected all the RT indicated flaws

• PAUT detected several additional areas of incomplete fusion

• PAUTdetectedallofthecracksintheexamvolume

• PAUT detected all of the cracks in the exam volume 14-100-CS SLAGRT ~1" lengthPAUT ~1" length 8-120-CS Incomplete FusionRT ~1" intermittent PAUT~1"length PAUT ~1 length 12-100-CS Incomplete PenetrationRT ~ 3/4" length PAUT~3/4"length PAUT 3/4 length (~1.2" in other direction) 8-120-CS PorosityRT ~1" lengthPAUT ~1" length 10-60-CS ID Crack (PT)

RR 48 Summary

• Additional restrictions (requirements) to N-659-2:

• Automated (encoded) Phased Array Ultrasonic Examination

• Allweldswillreceiveasurface(PTorMT)examination

• All welds will receive a surface (PT or MT) examination

• Weld caps will be ground flush

• Volume will be scanned in all 4 directions

• 100% coverage

• Volume will be scanned with a 0 degree

• Demonstration for each nominal diameter and thickness

• Data will be recorded for analysis and retention

• PSEwillbeinadditionandperASMESectionXI

• PSE will be in addition and per ASME Section XI Conclusion ConclusionRR 48 utilizes as a basis Code Case N-659-2RR48 requires additional restrictionsRR 48provides an acceptable level of quality and safety