ULTRASONIC PHASED ARRAY TRANSDUCER FOR THE NDE INSPECTION OF THE JET PUMP RISER WELDS AND WELDED ATTACHMENTS

Abstract

An ultrasonic phased array transducer assembly having a single housing in which a plurality of phased array transducer subassemblies are mounted at a skewed angle relative to a leading face of the housing and to each other, with each transducer mounted on composite wedge(s) at different orientations within the housing.

Claims

1-11. (canceled)

12. A method of inspecting welds of a pipe in a boiling water nuclear reactor using a phased array transducer assembly, the method comprising: positioning the phased array transducer assembly adjacent to a surface of the pipe such that a face of a housing of the phased array transducer assembly is positioned adjacent to a weld to be inspected; generating an ultrasonic beam using a phased array subassembly that is mounted on a wedge of the phased array transducer assembly and oriented at a first angle relative to the face of the housing of the phased array transducer assembly, wherein the wedge is positioned within an internal cavity of the housing of the phased array transducer assembly; and scanning the pipe, such that a range of the ultrasonic beam comprises an area encompassing the weld of the pipe.

13. The method of claim 12, wherein scanning the pipe further comprises scanning a range comprising a number of different angles.

14. The method of claim 13, further comprising detecting a flaw oriented axially and circumferentially relative to the weld based, at least in part, on the scan of the pipe.

15. The method of claim 12, wherein the face of the housing is contoured, and wherein the contour of the face is determined based, at least in part, on the surface of the pipe.

16. The method of claim 15, wherein the contour comprises a concave surface, and wherein the surface of the pipe is a convex surface.

17. The method of claim 12, wherein the housing further comprises a shoulder mount, and wherein the shoulder mount is configured to engage a gimbal configured to reposition the face of the housing relative to the pipe.

18. The method of claim 12, wherein at least a portion of the face of the housing is parallel to the weld of the pipe.

19. The method of claim 12, wherein the first angle is perpendicular relative to the face of the housing.

20. The method of claim 12, wherein generating the ultrasonic beam further comprises using a second phased array subassembly that is mounted on a second wedge of the phased array transducer assembly and oriented at a second angle relative to the face of the housing of the phased array transducer assembly, wherein the first angle is different than the second angle.

21. The method of claim 20, wherein the second wedge is positioned within the internal cavity of the housing.

22. The method of claim 20, wherein generating the ultrasonic beam further comprises using a third phased array subassembly that is mounted on a third wedge of the phased array transducer assembly and oriented at a third angle relative to the face of the housing of the phased array transducer assembly, wherein the third angle is different than the first angle and the second angle.

23. The method of claim 22, wherein the third wedge is positioned within the internal cavity of the housing.

24. The method of claim 22 wherein the phased array subassembly is positioned between the second phased array subassembly and the third phased array subassembly.

25. The method of claim 22, wherein the second angle and the third angle are opposite relative to one another.

26. The method of claim 22 wherein the second angle and the third angle are congruent relative to one another.

27. The method of claim 22, wherein the phased array transducer assembly comprises a conductive tether configured to connect the phased array subassembly, the second phased array subassembly, and the third phased array subassembly.

28. A method of inspecting welds of a pipe in a boiling water nuclear reactor using a phased array transducer assembly, the method comprising: positioning the phased array transducer assembly adjacent to a surface of the pipe such that a face of a housing of the phased array transducer assembly is positioned adjacent to a weld to be inspected; generating an ultrasonic beam using a first phased array subassembly, a second phase array subassembly, and a third phase array subassembly, wherein the first phased array subassembly is mounted on a first wedge, wherein the second phased array subassembly is mounted on a second wedge, and wherein the third phased array subassembly is mounted on a third wedge; and scanning the pipe, such that a range of the ultrasonic beam comprises an area encompassing the weld of the pipe.

29. The method of claim 28, wherein the first phased array subassembly is oriented at a first angle relative to the face of the housing, wherein the second phased array subassembly is oriented at a second angle relative to the face of the housing, wherein the third phased array subassembly is oriented at a third angle relative to the face of the housing, wherein the second angle is different than the first angle, and wherein the third angle is different than the first angle and the second angle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A further understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

[0015] FIG. 1 is a schematic view of one embodiment of the ultrasonic phased array transducer assembly, including element position, of this invention;

[0016] FIG. 2 is a top perspective view of the housing of the transducer assembly of FIG. 1;

[0017] FIG. 3 is a perspective view of the housing of the transducer assembly of FIG. 1.

[0018] FIG. 4 is a schematic view of the transducer assembly of FIGS. 1, 2 and 3 positioned over a pipe adjacent a weld to be inspected;

[0019] FIG. 5 is a rear view of the transducer assembly of FIG. 4 showing the curved face of the transducer housing similarly matching the curvature of the pipe; and

[0020] FIG. 6 shows the transducer of FIG. 1 positioned over a weld.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] As can be seen in FIGS. 1-6, the phase array transducer assembly 10 of this invention contemplates a single housing 12 containing at least two independent phased array transducers utilized for the ultrasonic inspection of a jet pump riser pipe and associated riser pipe attachment welds in a boiling water reactor. An advantage of a single housing containing multiple phased array transducer subassemblies mounted in different positions and angles, whose outputs are coordinated, but independently controlled, is that such a design would eliminate the need to utilize multiple probes for the detection of various flaws which may differ in their orientation. This invention allows the number of tool reconfigurations, and the number of tools and/or probes required to perform inspections to be minimized. Further, when scanning on a contoured surface such as a pipe 36, the phased array transducer assembly 10 must have a contoured surface 18 to maintain a fixed sound path distance from the transducer elements within each of the subassemblies to the area to be inspected. This requirement further explains the desire to minimize the number of custom transducer housings that are needed to be employed for a weld inspection. In addition, due to the unique placement and orientation of the phased array subassemblies 22, 24, and 26, a compact overall housing 12 can be fabricated which allows maximum access to the weld around adjacent obstructions in the surrounding areas. The housing 12 includes a side wall and an opposing second side wall, an end wall and an opposing face 38. The side walls, the end wall and the face define a housing cavity 28 in which the phased array transducers are mounted.

[0022] Phased array transducers contain a row or multiple rows of elements referred to as the phased array subassembly that establish the parameters of the ultrasonic sound beam's steering or sweeping capabilities. Phased array transducer housings typically contain phased array subassemblies that are mounted on individual wedges which classically function in unity with one another to generate the desired beams. A more detailed understanding of the operation of ultrasonic phased array transducers can be found in U.S. Pat. Nos. 4,149,420 and 5,563,346. The novel probe assembly 10 of this invention utilizes phased array subassemblies 22, 24 and 26 mounted on separate wedges 38 positioned at dissimilar orientations within the housing, functioning as independent transducers and is not reliant on a plural wedge combination to generate the desired ultrasonic beams. Alternately, the phased array subassemblies may be mounted on a single piece of material with individual wedge surfaces machined to orient the subassemblies in their proper position.

[0023] The independent transducer conductors are tethered together in a joint cable 16 through a single port 14 in the housing 12. The port 14 is located such that it will not impede the face or front of the transducer from positioning at or near the weld toe. The housing 12 may contain shoulder mounts 20 for hardware gimbals on each side such that the face or front 18 of the transducer 10 can be positioned at or near a weld toe. The housing face 18 in contact with the surface of the jet pump piping 36 is a contoured such as to maximize coupling to the piping, as can be seen in FIG. 5.

[0024] Each transducer 22, 24 and 26, contained within the housing cavity 28 is fixed on at least one composite wedge 38 such as to generate at least one ultrasonic sound beam. The wedge 38 provides a means to set the transducer array at an angle relative to the inspection surface such that different elements of the array are fixed at different elevations relative to the inspection surface.

[0025] The transducer claimed herein has at least two phased array assemblies mounted at a skewed angle from each other and relative to the front leading edge 18 of the transducer housing 12. In one preferred embodiment, the single housing 12 contains three phased array transducers 22, 24 and 26. The center transducer 24 and the corresponding wedge is mounted such that its primary or center ultrasonic beam is directed in a plane perpendicular to the leading edge/face 18 of the housing 12. The two transducers 22 and 26 mounted on the clockwise and counter clockwise side of the centered transducer 24 are positioned inside the housing such that their primary or center ultrasonic beam is directed at an angle skewed from a plane perpendicular to the leading edge/face 18 of the housing 12, where the primary ultrasonic beams face away from each other, oriented approximately ninety degrees apart (at approximately reciprocal angles). Alternative configurations such as two, four, or more independent transducers can be utilized in a single housing 12 and would be considered to be within the concept claimed hereafter. In addition, alternative positions of each array may be utilized such that the array perpendicular to the leading edge/face is not the center array.

[0026] FIG. 4 shows the phased array transducer assembly 10 positioned adjacent a weld volume, i.e., the weldment 34 and the heat effected zone 30. The base metal 32 of the pipe 36 is shown on either side of the weld volume. As previously mentioned FIG. 5 shows the face 18 of the transducer assembly 10 being closely matched with the curvature of the pipe 36. FIG. 6 shows the view of the transducer assembly 10, shown in FIG. 1, adjacent the pipe 36.

[0027] While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.