Use of phased array UT in lieu of RT at a nuclear power facility in the United States is presented along with lessons learned

1. Todd Blechinger / Jeff Devers: LMT, Inc.
William A. Jensen: NextEra Energy Point Beach
A Case Study of Phased Array UT Examination
in Lieu of Radiography

2. • Basic Concept
• Job Scope
• Point Beach Specifics
• Examination Equipment
• Planning Activities
• Implementation
• Lessons Learned/Conclusions
• Current Code & Utility Activities
Overview

3. Basic Concept
• In the Summer of 2008, while reviewing work scope for the
Unit 1 Extended Power Uprate (EPU) Project – Feedwater
Heater Replacement, the Point Beach Nuclear Plant (PBNP)
NDE Level III recognized that the Code used for the
installation of new Feedwater Piping would allow for the use
of Radiography or Ultrasonic examination (ASME B31.1,
2004 Edition)
• This appeared to present an opportunity to apply a high-
quality examination technology and save the site a sizable
amount of time/cost by reducing the impact of NDE on
other work groups.

4. ASME/ANSI B31.1 2004 Requirements
136.4.6 Ultrasonic Examination. When required by this Chapter (see Table
136.4), ultrasonic examination (UT) shall be performed in accordance with
Article 5 of
Section V of the ASME Boiler and Pressure Vessel Code and the following
additional requirements.
(A) The following criteria shall also be met when performing ultrasonic
examinations.
(A.l) The nominal thickness of the material being examined shall be greater
than ½ in. (13 mm).
(A.2) The equipment used to perform the examination shall be capable of
recording the UT data including the scanning positions. Where physical
obstructions prevent the use of systems capable of recording the UT data
including the scanning positions, manual UT may be used with the approval
of the Owner.
(A.3) NDE personnel collecting and analyzing UT data shall have
demonstrated their ability to perform an acceptable examination using
written procedures. The procedures shall have been demonstrated to yield
acceptable results when applied to a calibration block fabricated in
accordance with ASME Section V, Article 5, T-542.2.

5. Point Beach Specifics
• Located on Lake Michigan approximately 30 miles
southeast of Green Bay, Wisconsin.
• Two, two-loop Westinghouse pressurized water reactors
newly up-rated to approximately 624 MWe.
• Both units were scheduled for multiple outage EPU
activities, starting with Unit 1 in the Fall of 2008, then Unit
2 in the Fall of 2009 and the Spring of 2011, completing
with Unit 1 in the Fall of 2011.
• The EPU scope included replacing all 5 sets of Feedwater
Heaters, Main Feed Pumps and associated piping up to the
ASME Section XI boundary valve just outside containment.

6. The concept was originally brought forward due to the location of
the Unit 1 #4 and #5 Feedwater Heaters, radiography would
be extremely intrusive on the already tight outage schedule:
1. Heaters are within 40 feet of the entrance to the RCA.
2. Major foot-traffic routes traverse within 20-40 feet of the
area.
3. Similar issues existed on the Unit 2 side with the exception of
the RCA entrance.
Unit 1 - Location, Location, Location

7. Location of
Feedwater
Heaters
Entrance to RCA
General Layout of Unit 1 Turbine Building (26 ft)
Major Foot-
Traffic Routes
Open Above &
Below

8. Movement of a FW Heater To 26 ft. Elevation
Open space above (Turbine Deck)
Open space below

9. Impact of RT on the Outage
• Due to the thickness [>1.0 inch(2.54 cm)] and diameter
[16 and 18 inch (40.6 and 45.7 cm) NPS], there would be
at between 6 and 8 exposures per weld, at approximately
2-3 hours per weld. Co-60 would likely be used, thus
creating an exclusion zone which would cover portions of
all three elevations of the Unit 1 Turbine Building and a
portion of the Primary Auxiliary Building (PAB).
• The best estimated time for radiography (assuming no RP
holds, re-shots, etc.) was 5, 12-hour shifts.

10. Impact of RT on the Outage
• This would have likely stopped all work on the Low
Pressure Turbine overhaul (1 elevation above),
condenser work (adjacent and below), and all welding
associated with the FW Heater replacement.
• The Unit 1 & Unit 2 # 4 & 5 FW Heater Replacement
Projects were at or near Critical Path for much of the
outage without factoring in RT.
• RT would have caused a minute-for-minute delay in
essentially all FW Heater work as well as a number of
other projects in the vicinity.

11. Planning for UT
• Due to the way the first FW Heater Replacement was
planned, a construction vendor was responsible for the
turn-key installation.
• PBNP NDE personnel presented the idea of UT in lieu of
RT to NextEra / FPL EPU personnel and received initial
push-back due to issues with UT in lieu of RT at Seabrook
Station.
• After discussions with the Seabrook Level III, it was
obvious that UT was not the problem.
• In early August 2008, the PBNP Level III discussed the idea
with several vendors, including PBNP’s ISI vendor (LMT),
who agreed it was a great opportunity to use Phased
Array (PA-UT).

12. Planning for UT
• The PBNP Level III presented the information regarding
PA-UT and the advantages over RT to the construction
vendor site manager, and provided contact information
to LMT.
• EPU personnel received the recommendation and
recommended that the construction vendor contract
for UT in lieu of RT
• LMT received a contract from the installation vendor in
late August, which gave them only about five weeks to
prepare a technique, procure probes, develop a
procedure, etc.

13. Equipment Used
• LMT used the Zetec Omniscan® 32P-32 R PA system with
a custom-built hand scanner for data acquisition on the
complex geometries encountered during the
replacement. This would be upgraded to an automated
scanner in later outages.
• GE IT 2-D Matrix-Array probes with a nominal frequency
of 3.5 MHz.
• UltraVision® Software was used for analysis.

14. Equipment Used
UltraVision Ultrasonic Data Analysis Software
Features:
 Allows Analyst to Manipulate UT Data in multiple scenarios
to assist with flaw detection and characterization
 Data Analysis in multiple planes (3-D)
 Analysis of Merged Ultrasonic Data along with Raw
Ultrasonic Data
 Portability of Analysis workstation (Laptop PC) allows for in
field analysis
 Permanent digital record of examination results

15. Encoded PAUT Analysis Advantages
UltraVision Ultrasonic Data Analysis Software
3- Plane Data Analysis
 Flaw location can be visualized in Top, Side, and End views
 Hard copy of examination results available in all three planes
 Permits easy and precise mapping for detected defect removal

16. Top View (C-scan) very similar to RT results- flaw is
only recognized in one plane
UltraVision Ultrasonic Data Analysis Software

17. Side View (B-scan) not available with RT. Flaw
depth within
volume is an added dimension
UltraVision Ultrasonic Data Analysis Software

18. End View (D-scan) not available with RT.
Flaw location within volume is another added
dimension
UltraVision Ultrasonic Data Analysis Software

19. Demonstration Mockup
The following slides illustrate the results obtained on a Mock-up
with “manufactured” embedded fabrication flaws.
Mock-up specifics:
 16 in. (40.64 cm) SCH 100 (1.031 in. / 2.62 cm) A106 GrB Carbon Steel-
Narrow groove configuration

20. Mock-up Specifics
 13 Typical welding flaws
 Flaw placement spread throughout weld volume
 Flaw height for planar flaws typical for weld process
employed (SMAW)
 Several of the flaw lengths at ASME B31.1 threshold for
Accept/Reject

21. Mockup Flaws #1-7

22. Mockup Flaws #8-13

23. Mockup Flaw #1- Sidewall Lack of Fusion

24. Mockup Flaw #2- Slag Inclusion

25. Mockup Flaw #3- Sidewall Lack of Fusion

26. Mockup Flaw #4- Slag Inclusion

27. Mockup Flaw #5- Sidewall Lack of Fusion

28. Mockup Flaw #6- Slag Inclusion

29. Mockup Flaw #7- Cluster Porosity

30. Mockup Flaw #8- ID Root Crack

31. Mockup Flaw #9- OD Centerline Crack

32. Mockup Flaw #10- Lack of Penetration

33. Mockup Flaw #11- OD Connected Lack of
Fusion

34. Mockup Flaw #12- Internal Crack

35. Mockup Flaw #13- Start/Stop Lack of Fusion
(Axial)

36. First Implementation – U1R31 (Fall 2008)
• LMT and PBNP worked together to put a procedure
into the PBNP NDE format to ease approval and
any future changes.
• Rev. 0 of NDE-142, “Fully Encoded Phased Array
Ultrasonic Examination of Ferritic Piping Welds”
was issued on October 10, 2008.
• PA-UT of pre-fabrication welds commenced the
same day.
• After finding minor glitches in the procedure, Rev. 1
was issued on Oct. 24, with no delays in on-going
pre-fabrication work.

37. First Implementation – U1R31 (Fall 2008)
• Approximately forty (40) welds were examined
using a combination of semi-automated UT and
manual “pick-ups”.
• Zero welds were rejected by PA-UT
• An estimated $2.5 million in “lost” outage time was
saved from the use of PA-UT in lieu of RT.

38. First Implementation – U1R31 (Fall 2008)
Typical Completed Weld

39. First Implementation – U1R31 (Fall 2008)
Typical Completed Weld

40. Typical Work Environment

41. Typical Work Environment

42. Second Implementation – U2R30 (Fall 2009)
• Due to the change in installation vendors, a similar
series of discussions between PBNP and the
vendor ensued regarding the use of PA-UT in lieu
of RT.
• The installation vendor’s NDE staff liked the idea of
PA-UT but were hesitant about the use of PBNP’s
vendor of choice (LMT).
• This concern was worked through & the work went
very smoothly.
• One weld out of approximately 35 required repairs
due to an lack of fusion and multiple inclusions.

43. Second Implementation – U2R30 (Fall 2009)
Sidewall Lack of Fusion detected in a 16 in. (40.6 cm) Schd.
100 Carbon Steel field weld
• It should be noted that this particular weld was in a
very unfavorable location for the welder.

44. Second Implementation – U2R30 (Fall 2009)
Dye Penetrant examination results after weld removal

45. Third Implementation – U2R31 (Spring 2011)
• PBNP management had been convinced of the use
of PA-UT in lieu of RT was worth what appeared on
paper initially to be additional expense.
• This outage had approximately 35 welds & included
several welds in the façade area (unheated building
around the containment) due to temperatures
dipping to 10°F -15°F (-9° to -12°C) at night.
• The automated scanner with a water delivery
system was fully implemented during this outage
will great success.
• Although the overall outage was delayed due to
piping installation issues, there were zero rejects.

46. Final Implementation – U1R33 (Fall 2011)
• The work scope was essentially identical to the Unit
2 work in the Spring.
• This outage again included several welds in the
façade area, however the temperatures were much
warmer than in the Spring.
• The final weld exam was completed on November
25th, 2011 (the day after Thanksgiving)
• PA-UT again had zero rejects.

47. The Automated Scanner With H2O Delivery
System

48. The Welds

49. • ASME Task Group – Alternative NDE for Repair,
Replacement and Modification Activities (TG – Alt
NDE) met in Nashville on May 15, 2012.
• NRC report “UT in Lieu of RT Program Status for TG
Alt NDE” is out to committee members for comment
• Report provides information on a project currently
in progress to compare the effectiveness of UT
techniques and RT techniques in the detection of
fabrication flaws in ferritic piping samples;
• The NRC acknowledges that UT has great
potential to be used in lieu of RT for RRA and,
eventually, for new construction examinations.
Current Code Activities

50. • EPRI presented a draft of a proposed new Code
Case (not a revision to N-713).
• Code Case will provide rules substituting UT for
RT when repairs or replacements involve welds in
ferritic piping;
• Code Case will provide rules substituting UT for
RT when repairs or replacements involve welds
in ferritic piping;
• Proposed Code Case limits alternative to ferritic
piping welds only;
• Not enough data on austenitic piping welds to
support technical basis at this time.
Current Code Activities

51. • Key open topics remaining in the effort to complete
this Code Case include:
• Acceptance criteria:
• ASME Section III
• ASME Section XI
• RMS tolerance values during performance
demonstration
• Length sizing [0.75 in (19 mm)]
• Through-wall sizing [0.125 in. (3 mm)]
Current Code Activities

52. Areas that worked:
• The use of the ISI vendor for this work meant that the
vast majority of personnel had previously worked at
PBNP and were familiar with site processes.
• Use of a site-specific procedure allowed for relatively
quick processing of changes.
• Up-front involvement of the Authorized Inspector kept
questions during examinations to a minimum.
Conclusions

53. Areas that worked:
• Site NDE personnel were involved throughout the
process, which allowed a level of trust to be built with
the EPU organization during non-outage times. This
helped immensely when questions arose during
actual implementation.
• LMT provided basic training and a computer to the
site NDE Level III for data review which kept the AI
from bothering LMT data analysts as much.
Conclusions

54. Areas for improvement:
• Originally, LMT worked under contract to the
installation vendors, this was found to be very
cumbersome.
• At times, the installation vendor would report welds
as “waiting on NDE” to the EPU Team Room prior to
telling NDE they were ready.
Conclusions (Cont.)

55. Areas for improvement:
• EPU personnel determined mid-way through an
outage that they wanted 24/7 coverage based on the
installation vendor’s complaints. This caused LMT to
jump through hoops to get qualified personnel on site
quickly. This could have been averted by the
installation vendor providing feedback to PBNP NDE
/ LMT early in the outage.
Conclusions (Cont.)

56. Thank You for Your Attention