NUREG/CR-5985, Provides Summary of NUREG/CR-5985,PNL-8919,Supplement 1, Review of P-scan Computer Based Ultrasonic ISI Sys
| ML20236N388 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1998 |
| From: | Battige C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML20236K829 | List:
|
| References | |
| FOIA-98-188, RTR-NUREG-CR-5985 NUDOCS 9807150111 | |
| Download: ML20236N388 (5) | |
Text
.
f.
Note To : Weld Team From: Ken Battige
Subject:
Summary of NUREG/CR-5985, PNL-8919, Supplement.1
" Review of P-scan Computer Based Ultrasonic Inservice inspection System" P-scan is short for Projection image Scanning Technique. The equipment is built and operators trained by the Force Institute (the Danish Welding Institute). Force recommends Level 11 personnel to operate equipment, and Level 111 personnel to interpret and evaluate results Primarily intended for inservice inspection at nuclear power plants, semi-automatic operation can be conducted remotely after set-up.
A scanning unit is attached to the object to be examined, and scans in the "X"and "Y" directions.
The weld centerline is typically Y= 0, with a reference point set at X = 0, and the length of the weld along the X axis. The "Z" axis is depth into the object. See Attachment 1, Section 5.1.
P scan stores images, rather than raw ultrasonic data., on 3 %" diskettes. Visual output via color printer for permanent, reinspectable, records. (samples available)
P-scan has a very large dynamic range ( >100dB with the loganthmic amplifier), so no gain settings are used during data acquisition. No minimum threshold is set for signal recording (gating levels set during interpretation).
P-scan scans are done with multiple transducers concurrently.
Evaluation of indications according to amplitude is performed primarily during post-processing with a separate software program.
The P-scan data set includes three views: top, side, and and Side and End are relative to the weld, not the component (the reverse of normal).
All three views, along with other information, are presented for detection, sizing, and evaluation of flaws. A computer cursor is available to pin-point indications.
See Attachment 1, Section 5.2 for diagram.
P-scan system capabilities have been established through the qualification process.
Review Checklist for NRC Inspectors: See Attachment 2 ANO has used the P scan technique to examine the top portion of the MSB walls for 10 casks.
'This NUREG review based on one month of laboratory use at PNL. The NUREG is intended as a guide for NRC inspectors, and does not present any conclusions or recommendations on the system.
9807150111 990630 PDR FDEA M 'D LOO. ,-.PDR
~
/l .' p
- Attachment 1 P-scan 4
5.0 Ininge Interpretation 5.1 P-scan Axis Definition and Z exes for inspection of a circumferential weld.
Typically the weld centerline will be taken as Y=0. X-0 is preferably at a known reference point. Z increases toward the center of the pipe. A circular saw cut is shown in the outer surface of the weld zone.
Figw s 5.lB-D show the meaning of" Side view" and "End view"in P-scan terminology. Figure 5.IB shows side ad ad views of the same pipe shown in Figure 5.1A. Figure 5.lC shows the side and and views of the Y circular saw cut. Figure 5.lD shows the P-scan side and end views ofindications from the saw cut. Note that the X terms are reversed fmm what might be expected; this is because the words " side" and "and" refer not to the pipe, 7 but to the weld itself.
5.2 P-scan Axis Display Figure 52 is a diagrammatic presentation of a P scan image. Figures 5.2A, B, and D diagram the axis orien-tations for P-scan presentations. P-scan uses a rectangular 5ide End coordin8te system (in the C888 of 8 Pi Pe, treating the outer surface as though it were a plane), presented with the Z-axis down (larger positive Z means greater depth into the part). The X and Y-axes may begin at any number, Pice positive, negative, or aero; the Z axis normally begins at B 0 or a positive number (a negative Z value indicates data above the surface of the part). The Top View (A)is a C-scan view, showing the stepping (magnetic wheel crawler) e.xs (X) across and the scanning axis (Y arm) up, looking at the outside of the part, with the positive Z axis point-Scen i A ing into the paper. The Side View (B)is a B scan end C view, showing the stepping axis (X) across and the depth axis (Z) down, with the scanning axis pointing into the paper. Figure $2C shows an ultrasonic amplitude presen-tation called an Echo View, aligned with the side view.
The End View (D) is a B scan side view, showing the P-scan v i scanning axis (Y) across and the depth axis (Z) down, D with the stepping axis pointing into the paper. Figure 5.2E is an Echo View aligned with the End View. A screen display will show views A, B, and C or A, D, and Figure 5.1 P-scan axis deflaition E; a printed display may show the screen display or all five views.
Figure 5.1 diagrams the P scan axis and view definitions.
Figure 5.l A shows the typical orientation of the X, Y.
St.17 NUREG/CR 5985, Suppl.1
1 P-scan 1
1 101 234 5.4 P-scan Imaging Mode 3 X-Axis 2 Figure 5.3 shows a P scan image of test block UT RPT- !
, 1 TOP VIEW CIRC 1 (see Section 7.3 for notes on the geometry of the 0 block). It hu ban reproduced a 90% of actual sin to
,3
-I allow a vertical orientation on the page (scales for other #
101234 image mage 5% to 16).
O x-Axis 5.4.1 Top ofImare e 1 SIDE VIEW At apper lea, the print is identified as a P-scan image, as 2 2- *5 distinct from A scan or T-scan. De small numbers (0.000, 4.808, 4.985, 5.117, 5.205) printed vertically 101234 above the image are X-axis ranges for indications. The 60c9 x-Axis numbers *0.00 in" and "5.51 in" above the image (far left c 40 ee ECHO VIEW and right respectively) indicae the X axis (crawler axis) 20 es AuPUTuot Axis value at the left and right edges of the image, and also indicate that the dimensions are in inches rather than 321 0 -1 millimeters. The three other numbers "X 0.926," "Y 0 0.417," and "2 2.334" above the image give the X, Y, v-Axis o
""# **N ' " i"'*" I **" " #
- 1 END VIEW cron-hairs.
2 2-**'S 5.4.2 Top View Identification i 321 0 -1 so ce At the left side, " TOP VIEW" indicmes that the view is E 40 eB in se plane (w a Datened spreentmion of ee @er, j ECHO vtEW 20de AuPUTuDE Axis sphere, or other s sface) on which the probe travels.
" Top 5.00 in" means that the Y axis (scanner axis) extent of the TOP VIEW is 5.00 in. (12.7 cm), but it does not indicae the lower and upper bounds for Y-axis values.
Figure 5.2 P-scan axis presentation in this presentation, colors are assigned to images. Iml has a red block beside it, indicating that image 1 is represented by red areas on the image; im2 is yellow; Im3 is green; and im4 is dark blue. Any image portion in which the signal amplitude is below the " Lower" value 5.3 Imaging Modes indicated in the ECHO VIEW (see below) is shown in background color (grey in this image). In this file, Imag-There are two types ofimaging: P-scan and T scan. P-es 1-4 represent time goes 14, which were set at four scan is an amplitude presentation and T scan is a thick
- intervals through the block, gate I starting slightly below ness presentation. For either type, there are two modes:
the near surface and continuing to a depth of about 1.5 in.
Imaging and A scan. Imaging mode provides projected (4 cm), gates 2 and 3 following at greater depths, and data, whereas A scan provides full RF or video data.
gate 4 ending just past the far surface. The gate settings Most images for weld inspection are P scan Imaging; are shown diagrammatically in Figure 5.4 (the Probes and erosion' corrosion inspection uses T-scan Imagmg. A aan Gates diagram is further explained in Section 5.5); the mode is used only for evaluation, as it generates Lrge ,
exact settings are given in Table 4.31, as determined by a !
data sets.
data print out of the scan parameters (scan parameter printouts are detailed and explained in Section 15.2).
NUREGICR 5985 Suppl.1 St.18
r -- - - - - - - - - - - - - - - - - --- - -------- - -- -- - - - -- - ---- - - -
Attachment 2 P-scan 15.0 Review Checklist 15.1 Before and During Inspection Have the following uhrssonic persmass been properly set and noted?
Have reference standards been scanned to assure proper system operation and required sensitivity? Probe frequency Refracted angle Have scanner parameters been correctly recorded, either Skew mgle oh the computer, or by color photograph, or in writing? X and Y offsets Assure the correct recording of the following parammers Delay of shoe -
X MOTION Material v.clocity (shear or longitudmal as appro- l STEP (ON/OFF) priate) '
STEP SIZE (mm) Part thickness, width, and length CORRECTION FACTOR (+/-percent) A scan start and range CONT (ON/OFF) Gme starts and lengths SPEED (+/ mm/s) Ananuation, if used DIRECT 10N (CW/CCW) Probe reference levels, if used Y MOTION l
. NEAR END (+/ mm) For any parameters recorded in writing, have the corre-SPEED (mnvs) 8Ponding sections of the computer record been left blank FAR END (+/-mm) or made identical to the written record, so that there can
' be no confusion? Particularly, step size and speed?
Have positioning conventions been observed and clearly noted, and photographed if appropriate? Assure that the Has full coverage been assured? If any C-scan view is following have been noted: examined a !bil gain, there should be no areas of missing Zero angle reference marks or intermittent' data. Areas of missing data indicate lack Weld centerline of coverage. Areas ofinterament data indicate either Positioning of the scanner unit relative to the part Poor couplant or excessive speed relative to the repetition Clockwise / counterclockwise rue.
Scanner arm relative to flow direction Orientation of probe (s) In areas of muhiple overlapping indications, has A-scan Channel number for each probe data (which allows image manipulsion) been taken or real-time evaluation been performed?
Is scanner arm aero position correctly calibrated or noted?
In the unusual case of muhiple indications lined up along If a curved Y arm was used, has it been fbily described? both X and Y axes, have A-scans or subvolume scans Has the correction factor been set and recorded? been made?
If scanner is mounted on a pipe of different diameter than If RF or Rectified data won used to evaluate indications, the one being inspected, have both diameters been record- has an appropriate A-scan data set been recorded and ed and the appropriate correction factors entered (both on Printed?
the scanner control unit and in the software)?
Have all scanner em screws been checlIed for tighmess at Was the scanner mounted on a truck? If not, the final intervals durms the inspection? If found loose, has area position should be very carefully checked to ensure that b mscanned?
the scanner has not become undely skewed during the scan.
Has fmal scanner position been verified to w..,,cs.d to expected travel?
S t.91 NUREG/CR 5985, Suppl. I I
5
.- p. scan 9
Is each image clearly marked to indicate its position telative to the entire part scanned?
15.2 After Inspection j i
Have pnated images been made of all areas containing Ifimage Processing has been used, have the ongmal as well as the processed Bles been saved?
indications (at least for reportable indications; preferably for all indicsions evaluated)?
If welds longer than about I foot (30 cm) were scanned, Have prinued copies been made of all inspection param-were they scanned as separate sections (called " parts")7 stars set in the so8 ware? 4 This is imponant because the Bles can then be merged to view the entire weld, or viewed separately to achieve Have backup oopies been made of all data diskettes?
maximum tesolution.
Have printed images been carefully annotated? In if blank lines appear between the scans, verify that the particular, have beginning or ending coordmate values combination of beam width and scan increment indicates full coverage. been noted for Y and Z axes (the vertical axes in the pnoted image)?
Are image interpretations consistent with the length, width, and height scales?
i NUREG/CR 5985, Suppl. I S t.92 i 1
i
e I l fk1 l . From: Allen Howo /hr?IJ
! To: TJK1, EJL, FCS Date: 2/6/98 2:16pm M%,//mIJ I l
Subject:
SNC Phone Calls i
I called ANO, Keller & Dosa and discussed my trip next week.
I am scheduled to be at ANO 2/10 and 2/11.
l I called SNC, Moskel, wrt the trip next week and the 2/23? inspection. I also discussed the items in the letter regarding the 15 day clock for the proprietary affidavit and the notification of GTAW weld process qualification. His only question was why was the inspection a SNC 1 inspection? I basically told him it related to a SNC CAL corrective action verification.
(
! 4 i
l l
l
- l l
i I
l l
l
e l Mall Envelope Info: (34DB618E.A46 : 17 : 42080)
Subject:
SNC Phone Calls Creation Date: 2/6/98 2:16pm From: Allen Howe Created By: WND1.WNP7:AGH1 Recipients Action Date & Time Post Office WND1.WNP7 EJL (Eric Leeds)
FCS (Frederick Sturz)
TJK1 (Timothy Kobetz)
Domain. Post Office Delivered Route WND1.WNP7 Pending WND1.WNP7 Files Size Date & Time MESSAGE 483 02/06/98 02:16pm View 4109 02/06/98 09:16am Options Auto Delete: No Expiration Date: None Notify Recipients: No Priority: Normal Reply Requeste8: No Return Notification:: None Concealed
Subject:
No Security: Normal To Be Delivered: Immediate Status Tracking: AllInformation l