ML20065N435

Protocol for Demonstrating Performance of Ultrasonic Techniques for Identification & Sizing of Outside Diameter Surface-Connected Flaws

ML20065N435
Person / Time
Site:	Mcguire
Issue date:	03/24/1994
From:	DUKE POWER CO.
To:
Shared Package
ML20065N410	List: ML20065N408 ML20065N435
References
NUDOCS 9404270156
Download: ML20065N435 (15)

Text

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PROTOCOL FOR DEMONSTRATING TIIE PERFORMANCE OF ULTRASONIC TECHNIQUES FOR IDENTIFICATION AND SIZING OF OUTSIDE DIAMETER SURFACE-CONNECTED ' FLAWS Duke Power Company / EPRI NDE Center 3/3/94

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Prepared by: Y " "

• Date: I

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Reviewed by: nat . .. /d I # Date: 3////A/

(j u Approved by: Date: 3h.4f9f 0

E. Kim Klettman EPRINDE Center 3/1/9417D9 9404270156 940414 PDR ADOCK 05000370 0 PDR

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, l TAllLE OF CONTENTS  ;

1 1.0 GENERAL 1.1 Mock-up Descripdon 1.2 Flaw Description 2.0 EXAMINATION PROCEDURE 2.1 Essendal Vadables -

2.2 Procedure Requirements 3.0 ESSENTIAL VARIABLES 4.0 EXAMINATION GROUP COMPOSITION 4.1 Personnel Funedons 5.0 DEMONSTRATION PROCESS 5.1 Detection Phase 5.2 Analysis Phase 6.0 RESULTS REPORTING 6.1 Flaw Detection 6.2 Flaw Location Accuracy ,

6.3 Flaw Sizing l 7.0 DOCUMENTATION I

8.0 SECURITY l

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C 1.J GENERAL This document will serve as a guideline for the demonstration of candidate examination processes, procedures and equipment for in-service inspections performed by Duke Power Company. The performance demonstration will be conducted in a manner that addresses all pertinent parameters of the actual ISI. The performance demonstration is intended to establish the performance of ultrasonic techniques in detecting, characterizing, locating, and sizing of flaws in large diameter vessels.

Duke Power, with assistance from the EPRI NDE Center will serve as the performance demonstration administrator (PDA). Duties in this administrative capacity will include:

performance demonstration protocol development, examination procedure review, demonstration monitoring, demonstration results reporting, specimen security, and maintaining the necessary documentation used during the performance demonstration.

There will be no acceptance criteria. Duke Power will be responsible to determine whether the ISI procedure is adequate. Flaw detection, location and sizing results will be determined upon completion of data collection and analysis.

To insure the credibility of the demonstration process, the examination procedure must contain definitive steps for identifying flaw signals and sizing the flaw di.mensions.

Compliance with these procedural steps will be monitored during the demonstration.-The NDE Center will assist in evaluating the results of the demonstration. l l

1.1 Mock-up Description The vessel mockups employed will be a full-scale mpmsentations. The mockup will be made from production materials and will be mounted in a representative orientation.

1.2 Flaw Description Flaws manufactured using the HIP process, and notches will be employed.. A description of the flaws is included in Attachment A. Both axial and circumferential orientations will be included.

2.4 EXAMINATION PROCEDURE 2.1 Essential Variables Clearly identified essential variables. Unless otherwise stated in this document, the examination procedure shall identify parameters for the essential variables defm' ed in Section 3. Essential variables will be specified by a single value or a range of values in the examination procedure and detailed in the demonstration plan.

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4 2.2 Procedure Requirements The information specified in 2.2.1 shall be made available to the PDA prior  !

to the commencement of the demonstration. Any information considemd to be sensitive or confidential will be treated as such, and will be returned upon completion of the demonstration.

2.2.1 Examination system description.

2.2.1.1 System operation manual.

2.2.1.2 System software mvision number.

LD ICSSENTIAL VARIABLES 3.1 The examination procedure shall contain a statement of scope that specifically defines the limits of procedure applicability (e.g. materials, thickness, diameter, product form).

3.2 The examination procedure shall specify a single value or a range of values for all of the identified essential variables.

3.3 The examination procedure shall specify the following essential variables:

3.3.1 instrument or system, including manufacturer and model and series of pulser, mceiver, and amplifier.

3.3.2 search units, including:

(a) center frequency and bandwidth or waveform duration; (b) mode of propagation and nominalinspection angles;

• 4 (c) number, size, shape and configuration of active elements and I

wedges or shoes; 3.3.3 search unit cable, including; ]

(a) type; (b) maximum length; maximum number of connectors; I (c) 3.3.4 detection and sizing techniques, including:

(a) scan pattem and beam directions; (b) maximum scan speed; (c) minimum and maximum pulse repetidon rate; (d) minimum sampling rate (automatic recording systems);

(c) extent of scanning and-action to be taken for access restrictions; _

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3.3.5 methods of calibration for detection and sizing (e.g. actions required to insum that the sensitivity and accuracy of the signal amplitude and time outputs of the examination system, whether displayed, recorded, or automatically processes, are repeated from one examination to the next examination.

3.3.6 inspection and calibration data to be recorded; (a) method of data recording; (b) recording equipment (e.g., strip chart, analog tape, digitizing) when used; 3.3.7 method and criteria for the discrimination of indications (e.g.,

geometric versus flaw indication and for length and depth sizing of flaws);

3.3.8 surface condition requirements.

d.dt EXAMINATION GitOUP COMPOSITION He Vendor's procedure shall identify the responsibilities and qualification requirements for personnel carrying out the following functions 4.1 Personnel Functions 4.1.1 Examination system setup, calibration and data acquisition.

4.1.2 Reviewing acquired data and initial data screening.

4.1.3 19aw cha:acterization and sizing.

EJ1 DEMONSTitATION PitOCESS The demonstration will consist of two phases; detection and analysis.' No time limit will be imposed. All examinations must be successfully completed prior to disclosure of performance results.

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5.1 Detection Phase The detection phase will be performed in strict accordance with the formal procedure as specified in section 2.0. The region to be examined will be identified to the candidate by the PDA.

5.1.1 Calibration, acquisition, and data review steps will be performed by the appropriate candidates in accordance with the vendor's procedure.

5.1.2 The monitor may at any time during the detection phase, request an explanation or demonstration of a procedural step.

5.1.3 Upon completion of the detection phase, the candidate will complete standard detection results reports. At that time, all acquired data will be removed from system storage devices and transferred to the appropriate storage media.

5.1.4 The detection results and all acquired data generated will be transferred to the PDA.

1 5.2 Analysis and Flaw Characterization Phase I

The analysis and flaw characterization phase will be performed in strict accordance with the formal procedure specified in section 2.0.

5.2.1 The analysis phase will be performed by the appropriate personnel as .

identified in section 6.0. l 5.2.2 Detection data to be analyzed will be provided to the candidate by the PDA.

Other pertinent information may be requested if it is specifically identified in the Vendor's procedure and the demonstration plan.

5.2.3 The monitor may at any time during the analysis phase, request an explanation or demonstration of a procedural step.

5.2.4 Upon completion of the analysis phase, the candidate will complete formal analysis results report. At that time, all acquimd data will be removed from system storage devices and transferred to the appropriate storage media.

5.2.5 The formal analysis report and all acquired data generated will be' transferred to the PDA.

5.2.6 Re-looks or re-examinations may be performed as specified in the formal procedure.

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k A 4 6.0 RESULTS REPORTING The error in flaw location, characterizing, and sizing will be determined. Duke Power Co.

will be responsible to determine whether the perfonnance is adequate. RMS error of flaw depth sizing msults will be calculated. Linear regression analysis of the demonstration >

results may also be performed as an aid in evaluating performance.

LR DOCUMENTATION Upon completion of the demonstradon, all demonstration documentation will be reta'med by Duke Power Co.. This documentation include the ultrasonic data acquired on the specimens, NDE procedures, equipment identification, specimen information used during the demonstration, and the msults of the perfonnance demonstration.

fLJ1 SECURITY Duke Power and the EPRI NDE Center will be responsible for maintaining the test keys during the demonstration and ensuring the test sampics contain flaws which can be detected. ,

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ATTACHMENT A DEMONSTitATION MOCK-UPS  ;

The mock-ups employed in the demonstration contained cracks fabricated using hot isostatic processing (IllP). This fabrication method offers significant cost and scheduling advantages over other fabrication methods. The cracks can be produced with accurate knowledge of the size, shape, and location.

Cracks produced by other techniques such as by adding contaminants to welds are much mom difficult to accurately characterize. Another significant consideration is the possible introduction of untentional flaws. These flaws are referred to as " satellite" reflectors which are caused by porosity or small slag inclusions from welding process.

Considerable experimental evidence has been compiled supporting the equivalence of fabricated cracks and mechanical fatigue cracks from an NDE point of view. HIP is the pmferred method of implanting intentional cracks when high accuracy is requimd. This approach as illustrated in Figure 1 consists of:

1) fabricating cracks in laboratory specimens,

2) removing the crack and surrounding material,

3) machining the material into a simple shape such as a cylinder,

4) IIIP implanting the cylinder into a matching hole in the mock-up.

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This multi-step procedure allows for accurate confinnation of the flaw si7e during the manufacturing process. Prior to implantation into the mock-up, the flaw specimen can bc l i

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I Accurate characterization of the intentional flaws during construction of the practice and  !

perfom1ance demonstmtion mock-ups is of utmost importance to providing a meaningful demonstration. Backward-scatter and forward-scatter (TOF) tip diffraction ultrasonic techniques along with focussed probe techniques were performed to insure the highest degree of accuracy in flaw size estimates, i

Figures 4 to 6 show examples of ultrasonic examinations performed at various stages of mock-up l construction.

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ATTACllMENT 11 DEMONSTRATION RESULTS Initial procedure development and mfinement was performed on a sampling of flaws in the demonstration blocks described in Attachment A, and on additional NDE Center mock-ups. The remaining flaws in the demonstration blocks were reserved for the final demonstrations.

Upon completion of procedure development, areas of the block containing the flaws mserved for demonstration were identified to Duke Power personnel. Detection, characterization, and flaw sizing was then performed according to the formal protocol. The results were then evaluated by NDE Center personnel The linear regression analysis msults for flaw sizing are attached.

The demonstration results were then reviewed with Duke Power personnel. Results of the discussion were:

• The performance of the forward-scatter time-of-flight flaw sizing procedure was very good

• Flaw characterization and identification of the appropriate flaw tip signals could be improved by ir.corporating a supplemental backward-scatter ultrasonic technique

+ Modifications to the forward-scatter time-of-flight equipment which could enhance flaw characterization were identified:

Operator adjustment of ultrasonic pulse-width to optimize ultrasonic ,

resolution .l Increased resolution in display of signal amplitude (number of gray-scale levels) 12

O FLAW DEPTII SIZING RESULTS *

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• O e ENCLOSURE 2 i

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es Inform Staff of External UT inspection as substitute for llefore Outage internal UT Inspection

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1. Develop RP Dme estirnates for inspections to be D,tring Outage Perform Area grf nned.

Radiation Survey V

1. LadJer to insulation support and platform on insulation Install Access support under inspection area.

Equipment l

q Results: Fabrication discont/ gouge Not a Cntk I. Leave as found, Staff approval to

%.sual/ Video

> avoid funher reinspections, OR N Inspection s 2. Repair per Code Section XI(perfonn df NDE below) x Not Adequate As Found x f~ Surface for MT inspection

/ YES Perform Surface y __r --- Adequate p, , f Results: Fabrication discont/ gouge

( Determine if pososity vs linear crack)

[ Perform MT Mapa4 1. le ve as found, Staff approval to NO . Inspection avoid further reinspections, OR

2. Repair per Code Section XI (perform all NDE below) llaw not detected flaw detected Y Y

(  % / 3 Manual UT to locate Auto UT for

___ . p and size pennanent siting

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[ Results: 3

1. ! rave as found, Staff Concurrence / ,

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' Approval, OR Flaw < Code ~~ f >

2. Repair per Code Section XI Ilowable

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[l)Itrfonn resicw of UT techniques and Results:

revise fracture mcci,anica calculaimn

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1. Leave as famd. Staff Concurrence T.._ p j 4 a -. _ Inspection size

2) Repair if pmiNe + Re. inspect at next 2 periods, OR 1

( 2. Repair per Code Section XI Enclosure 2, Page 1 of 1 J l

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