Circular sampling tool

Circular sampling tool (0001) The present patent application claims the priority of the United States patent application no. 61 / 219,655, registered on June 23, 2009, which is incorporated in full in this description by reference.

FIELD OF THE INVENTION The present invention relates to a circular sampling tool.

State of the art A method of evaluating the service life of pressure tubes in nuclear reactors, such as CANDUs, requires the periodic removal of a tube. The samples are cut from the removed tube and analyzed for deuterium content. The deuterium concentration is then used as a measure of the life of the remaining pressure tubes. This approach is very expensive due to the long downtime required to remove and replace a pressure tube.

The attempt to provide in-situ sampling (without removing the pressure tube) presents many difficulties. The usefulness of obtaining a sample is hampered by the hard oxidized surface and the need to obtain the sample below the surface layer. In order to preserve the structural integrity of the tube and to avoid harmful residual stress, the sampling depth must be controlled and the sample region must be unchanged in geometry on all axes. Furthermore, the technique used to remove the surface material or sample must not involve excessive heating, as this affects the results of the subsequent analysis. Another difficulty is to recover the sample for analysis and to protect against particles remaining in the pressure tube.

C <2 Ο 1 1 - 0 1 4 5 3 -2 1 -05- 2010 (0005) Patent US4925621, published May 15, 1990, which is incorporated herein in its entirety by reference, describes a sampling tool used in pressure tubes, a patent that addresses the issues mentioned above. The sampling tool described allows in situ testing, the removal of the pressure tube not being necessary. The sampling tool contains two cutters and means for capturing the removed material. By axially moving the two milling cutters in the pressure tube, one milling cutter removes the surface oxide layer and the second milling cutter removes the sample for analysis. The cutters and the cutting operation are designed to avoid damaging the integrity of the pressure tube to allow it to remain in operation.

Although the sampling tool described above refers to the above difficulties, it proves impossible to obtain samples in some parts of the pressure tube. For example, as seen in Figs. 1, in a CANDU type fuel channel, the pressure tube 10 is connected to a mounting end (not shown), using a laminated connection 12. The sampling tool described above makes it difficult to obtain useful samples in the area of ​​the laminated connection, due to the high axial gradient of hydrogen / deuterium concentration and the circumferential corrugations 14 in the area of ​​the laminated connection.

0007 The paper presented at the 5th International Conference on the Maintenance of CANDU Reactors in November 2000, entitled Advanced Sampling Tools in the Pressure Tube written by K. Wittich and J. King, also presents sampling tools. Paper presented at the 7th International Conference on the Maintenance of CANDU Reactors in November 2005, entitled Innovation Sampling in the Laminated Pressure Tube (Circular Sampling Tool Technologies) written by B. Guler, J. King, and Wray R. also disclose sampling tools. Both papers are published by the Canadian Nuclear Society.

Cf 2 OI 1 - O î 4 5 5 - 2 I -05-2010 (0008 Therefore, a sampling tool is needed to address at least some of the difficulties mentioned above and at least some of the inconveniences present in the prior art.

Disclosure of the invention

0009 An object of the present invention is to provide a sampling tool, which has at least two cutters moving along the circumference, along a portion of an inner wall of a tube. One cutter removes part of the inner wall of the tube and the second cutter removes a sample from the inner wall of the tube, from a location in the tube highlighted by removing the portion of the inner wall of the tube.

0010 In one aspect of the invention, a circular sampling tool for obtaining a sample from an inner wall of a tube has a cylindrical body with a central axis, an opening in the cylindrical body, and a shaft arranged in the cylindrical body. along the central axis. A first cutter is functionally connected to the shaft for rotation with it. The first milling cutter moves radially between a retracted position in which the first milling cutter is arranged inside the cylindrical body at a distance from the central axis and an extension position in which the first milling cutter extends at least partially, by opening, at a second distance from central axis. The second distance is greater than the first distance. A first actuator is functionally connected to the first cutter for moving the first cutter between the retracted position and the extension position as well as the rotating shaft. The first actuator mechanically influences the first cutter through the retracted position. The second cutter is functionally connected to the shaft for rotation together with it and is arranged at an angle to the first cutter. The second milling cutter moves radially between a retracted position where the second milling cutter is arranged inside the cylindrical body one third away from the central axis and an extension position where the second milling cutter extends at least partially, by opening, to a fourth distance from the central axis. The fourth distance is greater than the third distance. The fourth distance is greater than the second distance. A second actuator is functionally connected to the second cutter for moving the second cutter between the retracted position and the extension position as well as the rotating shaft. The second device

A- 2 Ο 1 1 - 0 1 4 5 5 -2 1 -05- 2010 drive mechanically influences the second cutter through the retraction position. The second cutter is in the retracted position when the first cutter is in the extended position. The first cutter is in the retracted position when the second cutter is in the extended position. The rotation of the shaft causes the first cutter to move to the extension position, and thus a portion of the inner wall of the tube is cut and then causes the second cutter to move to the extension position, therefore, the sample is cut from the wall. inside the tube from a location in the tube highlighted by cutting the portion of the inner wall of the tube.

0011 In a further aspect of the invention, the first actuator has a spring that mechanically influences the first cutter to the retracted position. The second actuator has a spring that mechanically influences the second cutter to the retracted position.

0012 In another aspect of the invention, a ramp is arranged inside the cylindrical body along a portion of the corresponding circumference. The ramp is located on the opposite side of the opening. The first actuator also has a first roller. The first roller causes the first milling cutter to move to the extended position when the roller runs over the ramp. The second actuator also has a secondary roller. The secondary roller causes the second cutter to move to the expand position when the roller runs over the ramp.

0013 In a further aspect of the invention, a diameter of the first roller is larger than a diameter of the secondary roller.

In another aspect of the invention, the first milling cutter is larger than the second milling cutter.

In a further aspect of the invention, a circular arc defined by the first milling cutter in the extending position as well as the rotating shaft is much longer than a circular arc defined by the second milling cutter in the extension as well as the rotating shaft.

^ -2011-01455-2 1 -05- 2010 In another aspect, a first container is connected to the first milling cutter for receiving the portion of the inner wall of the tube cut by the first milling cutter, and a second container is connected to the second milling cutter for receiving the sample cut by the second milling cutter.

In a further aspect of the invention, at least one spring is connected to the first cutter to influence the first cutter against the inner wall of the tube when the first cutter is in the extending position, and at least one spring is connected to the second cutter for influencing the second milling cutter against the inner wall of the tube when the second milling cutter is in the extending position.

In another aspect of the invention, the first milling cutter is arranged opposite the second milling cutter.

In a further aspect, at least one spring is connected between the first and the second milling cutter. At least one of the springs influences the first and second milling cutters away from each other.

In another aspect of the invention, a motor is arranged in the cylindrical body and is functionally connected to the shaft for its rotation.

In another aspect, a tool for obtaining a sample from an inner wall of a tube has a cylindrical body with a central axis, an opening in the cylindrical body, a shaft arranged in the cylindrical body along the central axis , an extension ramp connected to the cylindrical body, and a retraction ramp connected to the cylindrical body. A first cutter is functionally connected to the shaft for rotation together with it. The first milling cutter can be moved radially between a retracted position if the first milling cutter is arranged inside the cylindrical body at a first distance from the central axis and an extension position if the first milling cutter extends at least in part by opening , at a second distance from the central axis. The second distance is greater (λ- 2 Ο 1 1 - Ο 1 4 5 3 - 2 1 -05- 2010 than the first distance. A first actuator is functionally connected to the first cutter for its movement between the retraction position and the extension position by interacting with the retraction and expansion ramp, respectively, as well as the rotating shaft. The second cutter is functionally connected to the shaft for rotation with it and is arranged at an angle to the first cutter. The second milling cutter is movable radially, between a retracted position if the second milling cutter is arranged inside the cylindrical body at a third distance from the central axis and an extension position if the second milling cutter extends at least in part, by opening, at a fourth distance from the central axis. The fourth distance is greater than the third distance. The fourth distance is greater than the second distance. A second actuator is functionally connected to the second milling cutter for moving it between the retraction position and the extension position by interacting with the retraction and extension ramp, respectively, as well as the rotating shaft. The second cutter is in the retracted position when the first cutter is in the extended position. The first cutter is in the retracted position when the second cutter is in the extended position. The rotation of the shaft causes the first cutter to move to the extension position, and thus cuts a portion of the inner wall of the tube and then causes the second cutter to move to the extension position, therefore, the sample is cut from the wall. inside the tube from a location in the tube highlighted by cutting the portion of the inner wall of the tube.

In a further aspect, the first actuator includes a first actuator bar generally arranged parallel to the central axis. The first drive bar has a roller at a corresponding first end, a second roller at a second end and at least a third roller between the first and second ends. The second actuator includes a secondary actuator bar, generally arranged parallel to the central axis. The secondary drive bar has a fourth roller at a first end, a fifth roller at a second end and at least a sixth roller between the first and second ends. The extension ramp generally extends parallel to the central axis, towards the first and second milling cutters, and defines an arc of a circle around the central axis. The retraction ramp generally extends parallel to the central axis towards the extension ramp and towards the first and second milling cutters, and defines an arc of

Ck- 2 O 1 1 - OU 5 5 - 2 1 -05- 2010 circle around the central axis. The first and second milling cutters are arranged between the extension ramp and the retraction ramp, in a direction parallel to the central axis. A first bracket is connected to the first cutter. The first support has at least one defined channel, at an angle to the central axis. At least one channel of the first support receives at least the third roller inside. A second bracket is connected to the second cutter. The second support has at least one defined channel, at an angle to the central axis. At least one channel of the second support receives at least the sixth roll. When the first roller runs over the extension ramp, at least the third roller moves in at least one of the channels of the first support, which causes the first support to move radially away from the central axis, thus causing the first cutter to move. move to extension position. When the second roller runs over the retraction ramp, at least a third roller moves in at least the channel of the first support which causes the first support to move radially towards the central axis, thus causing the first milling cutter to move to the retraction position. When the fourth roller runs over the extension ramp, at least the sixth roller moves in at least the channel of the second support, which causes the second support to move radially away from the central axis, thus causing the second support to move. the second cutter to move into the extension position. When the fifth roller runs over the retraction ramp, at least the sixth roller moves in at least one of the channels of the second support, causing it to move toward the center axis, causing the secondary support to pass. in the retracted position.

In another aspect of the invention, the extension ramp has a first and a second ramp portion. The first portion of the ramp is larger than the second portion of the ramp. The first roller runs over the first ramp portion of the extension ramp and the fourth roller moves over the second ramp portion of the extension ramp.

¢ (-2 0 1 1 - 0 1 4 5 3 -2 1 -05- 20W In another aspect of the invention, the extension ramp has a first and a second ramp portion. The first ramp portion is more greater than the second portion of the ramp.The first roller runs over the first ramp portion of the extension ramp and the fourth roller runs over the second ramp portion of the extension ramp.

In a further aspect of the invention, the retraction ramp has a first portion and a second ramp portion. The first portion of the ramp is larger than the second portion of the ramp. The second roller runs over the second ramp portion of the retraction ramp and the fifth roller runs over the first ramp portion of the retraction ramp.

In another aspect of the invention, the first cutter is larger than the second cutter.

In a further aspect of the invention, a circular arc defined by the first cutter in the extended position, as well as the rotating shaft, is longer than a circular spring defined by the second cutter in the extended position, as well as the rotating shaft.

In another aspect of the invention, a first container is connected to the first cutter for receiving the portion of the inner wall of the tube cut by the first cutter and a second container is connected to the secondary cutter for receiving the sample cut by the secondary cutter.

In a further aspect of the invention, at least one spring is connected to the first milling cutter for its influence against the inner wall of the tube when the first milling cutter is in the extension position and at least one second circular spring is connected to a second cutter to influence it against the inner wall of the tube when the second cutter is in the extended position.

In another aspect of the invention, a motor is arranged in the cylindrical body and is functionally connected to the shaft, for its rotation.

Embodiments of the present invention each have at least one of the ^ -2 0 1 1 - 0 1 4 5 5 -2 1 -05- 2010 Τ the objects and l or aspects mentioned above, but not necessarily all of them. among them. It is to be understood that some aspects of the present invention which have resulted from the attempt to achieve the above-mentioned objects may not satisfy those objects and / or may satisfy other objects not included herein.

Additional and / or alternative features, aspects and advantages of the embodiments of the present invention will become apparent from the following description accompanied by the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE EXPLANATORY DRAWINGS For a better understanding of the present invention, as well as other aspects and other features thereof, reference is made to the following description, which is to be presented in connection with the explanatory figures, which represent:

Figure 1 is a cross section of the portion of a pressure tube showing the laminated connection area;

Figure 2 is a scale representation of a circular sampling tool;

Figure 3 is a cross-sectional view of a circular sampling tool in Figs. 2 taken along line AA in fig. 2;

Figure 4 is a cross-sectional view of a circular sampling tool in Figs. 2 taken through the line CC in fig. 2;

Figure 5 is a cross-sectional cross-sectional view of a circular sampling tool of Figs. 2 taken along line BB in fig. 2;

Figure 6 is a cross-sectional view of a circular sampling tool in Figs. 2, taken through the line DD in fig. 2, as well as portions which are taken by the line EE and FF of fig. 2;

_λ-2 0 1 1 - 0 1 4 5 5 - 2 1 -05- 2010 \ [0039] Figure 7 is a cross-sectional view of a portion of a pressure tube where a sample was obtained using a circular tool. sampling of FIG. 2 ;

Figure 8 is a cross-sectional view of a circular sampling tool according to an alternative embodiment;

Figure 9 is a cross-sectional view of a circular sampling tool in Figs. 8 taken along the line GG in fig. 8;

Figure 10 is a front view of an extension ramp of the circular sampling tool of Figs. 8;

Figure 11 is a side view of the extension ramp of Figs. 10;

Figure 12 is a front view of a retraction ramp of the circular sampling tool of Figs. 8; and Figure 13 is a side view of the retraction ramp of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The circular sampling tool according to the present invention will be described as being used to obtain samples from the pressure tubes of nuclear reactors to be analyzed for deuterium content. However, it should be understood that the circular sampling tool could be used to collect other types of samples from other types of tubes or from arched surfaces.

Returning to FIG. 2 and 3, an embodiment of a circular sampling tool 20 will be described. The tool 20 has a cylindrical body 22 with a central axis 24. The cylindrical body 22 has a plurality of support supports 26 for support ¢ (- 2 0 1 1 - 0 1 4 5 5 -2 1 -05- 2010 of the tool 20 when it is arranged inside the pressure tube An opening 28 is defined in the cylindrical body 20. A cutting assembly 30, described in detail below, is arranged inside the cylindrical body 20 longitudinally aligned with the opening 28. The cutting assembly 30 is supported by a transport means 32. The transport means 32 is connected by means of a coupler 34 to an output shaft 36 of an electric motor 38. The electric motor 38 is used to rotate the cutting assembly 30 which will be described in detail below. Preferably, the electric motor 38 is a direct current motor, but other types of motors are also considered. It is important that the motor 38 could be coupled to the cutting assembly 30 differently. For example, the output shaft 36 of the motor 38 could be connected to a drive shaft which in turn is connected to the means of transport 32. A cleaning tube 40 is connected to the cylindrical body

22. The cleaning tube 40 is used to dry the surface of a pressure tube if a sample is ready to be collected, as described below.

The circular sampling tool 20 is part of a circumferential sampling system, having some of the features that will be briefly described. The tool 20 is connected to a positioning system that allows the exact axial and angular positioning of the tool 20 in the pressure tube. A protective sleeve is arranged above the tool 20 when it is not pushed inside a pressure tube, which thus closes the opening 28. The tool 20, the positioning system, and the protective sleeve are arranged on a support bogie, which is preferably with wheels to facilitate its position.

To obtain a sample from the inner wall of a pressure tube (including a laminated connection region), the bogie is first rotated to the position adjacent to an open end of the hollow tube. The open end of the tube has an end gasket. The protective sleeve is then connected to the end gasket. The positioning system is used to set the angular and axial position if the sample is ready to be collected inside the tube. As can be seen from the description of the cutting assembly 30 below, the cutting assembly 30 uses gravity to collect samples, and therefore the sample is normally collected from r> -2 0 1 1-0U55-2 1 -05 - 2010 the upper half of the tube (ie between 09 and 3 o'clock of the clock position). The tool 20 is then pushed inside the tube so that the cutting assembly 30 is passed to the place where the sample is ready to be collected. An air removal operation is then performed using the cleaning tube 40 to dry the location where the sample is ready to be collected. The tool 20 is then moved back inside the tube so that the cutting assembly 30 is aligned with the location where the sample is ready to be collected. The tool 20 is locked in this position and the support supports 26 are actuated to hold the tool 20 in position by pressing against the inner wall of the tube. The motor 38 is then driven, thus causing the cutting assembly 30 to rotate about the central axis 24. As it rotates, the cutting assembly cuts a portion of the inner wall of the tube in a circumferential direction thereof, thus obtaining the sample. . Further details on this step will be provided below when describing the cutting assembly 30. The tool 20 is then unlocked, having the support supports 26 released, and the tool 20 is retracted back inside the protective sleeve. The sample contained in the cutting assembly 30 is then transferred to a flask contained in the means of transport. The above steps (starting with establishing the angular and axial position if the sample is ready to be collected) can be repeated to obtain samples in other locations in the tube. After all the samples have been collected, the protective sleeve is disconnected from the end gasket and the means of transport is moved away from the pressure tube. Finally, the flask (s) containing the sample (s) is (are) found. The above steps refer to a possible method of inserting the tool 20 inside a pressure tube to obtain samples. It should be understood that other methods of introducing tool 20 are possible and envisaged.

Returning now to FIG. 3 to 6, the cutting assembly 30 will be described. The cutting assembly includes an oxide cutter 50 and a sample cutter 52 arranged opposite each other. It is expected that the oxide cutter 50 and sample 52 could be arranged at other angles to each other. For example, it is intended that the oxide cutter of 50 and sample 52 could be arranged perpendicular to each other. Oxide milling cutters of 50 and sample 52 are preferably made of <201 1 - O 1 4 5 5 - 2 1 -05- 2010 carbides. The oxide cutter 50 is larger than the sample cutter 52 for the reasons explained below.

The oxide cutter 50 is connected by a threaded fastening means 54 to a drum 56 of the oxide cutter. A bracelet 58 is connected to the drum 56 of the oxide cutter. The bracelet 58 retains a portion of the tube for cutting through the oxide cutter 50 inside a container 60 formed between the oxide cutter 50, the drum 56 of the oxide cutter, and the bracelet 58, as will be explained below. The drum 56 of the oxide cutter is connected by a bayonet mount 62 to a support 64 of the oxide drum.

Similarly, the test cutter 52 is connected by a threaded fixing block 66 to a drum 68 of the sample cutter. A bracelet 70 is connected to the drum 68 of the test cutter. The bracelet 70 retains a sample cut through the sample cutter 52 inside a container 72 formed between the oxide cutter 52, the drum 68 and the bracelet 70, as will be explained below. The sample cutter drum 68 is connected by a bayonet mount 74 to a sample drum holder 76.

Two spring stacks 78 of the Belleville type are arranged between the support 64 of the oxide milling drum and the support 76 of the sample drum, which thus influences the two milling cutters 50, 52 far from each other. A threaded fastening means 80 is inserted into the support of the sample drum 76 and adjoins the support of the oxide drum 64, thus retaining the springs 78 between them. It is considered that other types of springs could be used instead of Belleville springs 78.

As will be described below, the milling cutters 50 and 52 are each movable (With the rest of the cutting assembly 30) between a retracted position where they are arranged inside the cylindrical body 22 and an extension position in the case wherein they extend in part through the opening 28 to cut the inner wall of the tube. The actuator for the oxide cutter 50 consists of two rollers 82 connected to the side of the drum of the test cutter 68 (see Fig. 3) and four springs 84. The rollers 82 are used to move the oxide cutter 50 to the extension position, as will be described below. Two of the springs 84 are connected to the support 64 of the oxide drum by two spring rounds 86 and two of the cv-2 0 1 1 - 0 1 4 5 5 -2 1 -05- 2010 the springs 84 are connected to the drum support 76 through two other spring washers 86 (see Fig. 5). The springs 84 influence the oxide cutter 50 relative to its retracted position. The actuator for the test cutter 52 consists of two rollers 88 connected to each side of the drum of the oxide cutter 56 (see Fig. 3) and the four springs 84. The rollers 88 are used to move the test cutter 52 to the position extension, as will be described below. The springs 84 influence the test cutter 52 to its retracted position. As can be seen in Figs. 3, the diameter of the rollers 82 is larger than the diameter of the rollers 88, for the reasons discussed below. It is envisaged that the oxide and sample cutters 50, 52 could be actuated by other types of actuators. For example, it is anticipated that the rollers 82, 88 could be replaced with fixed cams.

As best seen in Figs. 6, a ramp 90 is arranged inside the cylindrical body 22 along a circumferential portion. As can be seen, the ramp 90 is arranged opposite the opening 28. As discussed above, the rollers 82, 88 roll over the ramp to move the milling cutters 50, 52 to their extension positions.

The method by which the cutting assembly 30 cuts the sample to be analyzed from the inner wall of the tube will now be described . The motor 38 turns the drum 32 in the direction indicated by the arrow 92 in Figures 4 and 6, thus turning the cutting assembly 30 in the same direction. When the rollers 82 run over the ramp 90, the cutting assembly 30 moves upwards, thus moving the oxide cutter 50 to its extension position through the opening 28. Also, the rollers 82 run over the ramp 90, the oxide cutter 50 moves in an arc of a circle along the circumference of the inner wall of the tube and cuts a layer of oxide from the inner wall of the tube. In a preferred embodiment, the oxide cutters 50 cut a little deeper than the oxide layer to ensure complete removal of the oxide. The bracelet 58 causes portions of the oxide layer to curl inside the container 60. Belleville 78 springs influence the oxide cutter 50 against the surface of the tube, thus providing a shear force that allows the cutter to maintain contact with the surface which may be uneven and allow the tool 20 to be us ed in a variety of diameters. pressure tube. When the rollers 82

Cr2 O 1 1 - o 1 4 5 5 - 2 1 -05- 20W exceed the ramp 90, the springs 84 influence the cutting assembly 30 back towards the inner wall of the cylindrical body 22, and therefore the oxide milling cutter 50 returns to the position its retraction. Once the oxide cutter 50 no longer comes into contact with the inner wall of the tube, the portion of the oxide layer falls inside the container 60.

The cutting assembly 30 then continues to rotate. When the rollers 88 rotate over the ramp 90, the cutting assembly 30 moves upward, thus moving the test cutter 52 to its extension position through the opening 28. As the rollers 88 rotate over the ramp 90, the test cutter 52 moves in an arc of a circle along a circumference of the inner wall of the tube and cut a sample from the inner wall of the tube at the place where the oxide layer was cut. The bracelet 70 causes portions of the sample to curl inside the c ontainer 72. Belleville springs 78 influence the sample cutter 52 against the surface of the tube, thus providing a cutting force, which allows the cutter to maintain contact with the surface which may be uneven surface. and allowing the tool 20 to be used in a variety of diameters of the pressure tube. When the rollers 88 exceed the ramp 90, the springs 84 influence the cutting assembly 30 back to the inner wall of the cylindrical body 22, and therefore the test cutter 52 returns to its retracted position. Once the sample cutter 52 no longer comes into contact with the inner wall of the tube, portions of the sample fall inside the container 72.

The test cutter 52, when in the position indicated in Figures 4 and 6, is arranged next to the central axis 24 differently from the oxide cutter 50, thus determining that the test cutter 52 cuts deeper than the oxide cutter 50. Therefore, as can be seen in Figs. 7, the depth Ds for cutting through the sample cutter 52 is greater than the depth Do for cutting through the oxide cutter 50. Also, as previously mentioned, the sample cutter 52 is narrower than the oxide cutter 50. Therefore, as can be seen in Figs. 7 the width of the cutting edge Ws made by the test cutter 52 is smaller than the width Wo made by the oxide cutter 50. While the rollers 88 have a smaller diameter than the rollers 82, the circular arc defined by the test cutter 52 moving against the surface of the inner wall of the tube is smaller than the circular arc defined by the oxide cutter

Ο; 2 0 1 1 - Ο '4 5 5 - - ι ρ

1 -05- 2010 ^[ί / moving against the surface of the inner wall of the tube. Therefore, the sample portion is smaller than the oxide layer portion. The deeper, narrower and shorter cut made by the sample cutter 52 ensures that the sample is free of oxide, thus ensuring a reliable analysis of the deuterium concentration of the sample, which can be used to determine the service life. useful of a pressure tube. Also, because the milling cutters 50, 52 have moved on the circumference of the inner wall of the tube, they are not affected by surface variations in the axial direction of the tube. Therefore, the tool 20 can be used to obtain samples in the laminated connection region of the pressure tube.

Returning now to FIG. 8 - 11, an alternative embodiment of the circular sampling tool 20 (circular sampling tool 120) will be described. For simplicity, the characteristics of the tool 120, which are similar to those of the tool 20, have been labeled with the same reference marks and will not be described in detail again.

The tool 120 is provided with a cutting assembly 130. The cutting assembly 130 is rotated by a drive shaft 100 connected to the motor 38 (not shown in this example). As can be seen in Figs. 8, the cutting assembly 130 has two oxide cutters 50A, 50B and two sample cutters 52A, 52B. The two 50A, 50B oxide cutters are arranged opposite each other. Similar to the two test cutters 52A, 52B are arranged opposite each other. The test cutters 52A, 52B are arranged perpendicular to the oxide cutters 50A, 50B. Each of the milling cutters 50A, 50B, 52A, 52B is connected to a drum and to a suitable drum support and has a suitable bracelet, container and fasteners, as well as the cutting assembly 30. Therefore, for simplicity, these elements have been labeled with the same reference marks as in the cutting assembly 30, with the addition of the corresponding suffix A or B, as appropriate, and will not be described in detail again.

Each of the milling cutters 50A, 50B, 52A, 52B and is movable radially between a retracted position if it is arranged inside the cylindrical body 22 and an extension position if it extends in part by

V 2 Ο 1 1 - Ο 1 4 5 5 - 2 1 05- 2010 opening 28 to cut the inner wall of the tube. In a preferred example, the distance between the oxide cutter 50A and the center shaft 24 in its extension and retraction positions corresponds to the distance between the oxide cutter 50B and the center axis 24 in its extension and retraction positions, and the distance between the test cutter 52A and the central axis 24 in the extension and retraction positions corresponds to the distance between the test cutter 52B and the central axis 24 in its extension and retraction positions. in FIG. 8, the milling cutters 50B, 52A, 52B are in their respective retracted position and the milling cutter 50A is in its extension position. Each of the milling cutters 50A, 50B, 52A, 52B is provided with an actuating device for moving between the two positions as well as the rotating cutting assembly. Unless otherwise indicated, the actuators for each of the 50A, 50B, 52A, 52B milling cutters are the same and operate the 50A, 50B, 52A, 52B milling cutters in the same way. Therefore, only the 50A oxide cutter actuator will be described in detail.

As seen in Figs. 9, the oxide cutter actuator 50A includes a actuator bar 132A, generally arranged parallel to the central axis 24. The actuator bar 132A has a roller 134A at a first end, a roller 136A at the second end, and two rollers 138 A between its two ends. As can be seen, the roller 134A is larger than the roller 136A, for the reasons explained below. In the actuator for the test cutters 52A and 52B, the relative width of the end rollers is opposite (eg the roller corresponding to the roller 134A is narrower than the rollers corresponding to the roller 136A), for the reasons explained below. The two rollers 138A are received in two channels 140A formed at the bottom of the oxide support 64A. As can be seen, the two channels are arranged at an angle to the central axis 24. The actuator bar 132A is made in two parts 142A and 144A. Part 142A is received inside the part 144 A and can move axially relative to part 144. Stacks of Belleville 146 A springs influence the two parts 142A 144A far from each other.

An extension ramp 150 is arranged inside and is connected to the upper part of the cylindrical body 22. As can be seen in Figs. 10, the extension ramp 150 defines an arc of a circle around the central axis 24. The extension ramp 150 generally extends parallel to the central axis 24 towards the assembly of

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cutting 130. As shown above, the roller 134A runs over the extension ramp 150 to move the oxide cutter 50A to its extended position.

A retraction ramp 152 is disposed inside and is connected to the bottom of the cylindrical body 22. As can be seen in Figs. 12, the retraction ramp 152 defines an arc of a circle around the central axis 24. The retraction ramp 152 generally extends parallel to the central axis 24 towards the cutting assembly 130 and the extension ramp 150. As presented above, the roller 136A runs over the retraction ramp 152 to move the oxide cutter 50A to its extended position.

As can be seen in Figures 10 and 11, the extension ramp 150 has long portions 154 and a short portion 156. The rollers 134A, 134B of the oxide milling cutters 50A, 50B run over the long portions 154. The rollers corresponding to the actuators of test cutters 52A, 52B, which are narrow, run over the short ramp portion 156.

As can be seen in Figures 12 and 13, the retraction ramp 152 is longer than the extension ramp 150, and similarly has long portions of the ramp 155 and a short portion 157. Narrow rollers 136A, 136B of the retractors drive of the oxide milling cutters 50A, 50B runs over the short portion of the ramp 157 of the retraction ramp 152. The corresponding rollers of the actuators of the test cutters 52A, 52B, which are wide, run over the long portions of the ramp 155 of the retraction ramp 152.

So that the motor 38 turns the cutting assembly 130 in the direction indicated by the arrow 158 in FIG. 8, the roller 134A runs over the long portions 154 of the extension ramp 150. This leads to the axial movement of the drive bar 132A to the left in Fig. 9. As the actuator bar 132A moves to the left (as seen in Fig. 9), the rollers 138A push against the channels 140A, which, due to their angle relative to the central axis, cause the support of the oxide drum 64A to move upwards. Therefore, the 50A oxide cutter moves to its extension position through the opening 28. As the roller 134A runs over &lt;Α- 2 Ο 1 1-01455-2 1 -05- 2010 ramp 150, the oxide cutter 50A moves in an arc of a circle along a circumference of the inner wall of the tube and cuts a layer of oxide on the inner wall of the tube. In a preferred embodiment, the 50A oxide cutter cuts slightly deeper than the oxide layer to ensure complete removal of the oxide. The bracelet 58A causes portions of the oxide layer to curl inside the 60A container so that they are cut. Belleville 146 A springs influence the 50A oxide cutter against the surface of the tube, thus providing a shear force, which allows the cutter to maintain contact with the surface which may be an uneven surface and which allows the tool 120 to be used in a variety of diameters of the pressure tube. As the motor 38 continues to rotate, the roller 136A rotates over the short portion 157 of the retraction ramp, and thus the roller 134A exits the extension ramp 150A. This causes the actuator bar 132A to move axially to the right in Fig. 9. So the drive bar 132A moves to the right (as seen in Fig. 9), the rollers 138 A push against the channels 140A, which, due to their relative angle to the central axis 24, cause the support of the oxide drum 64A to move downwards. Therefore, the 50A oxide cutter moves to its retracted position. Once the 50A oxide cutter is not in long contact with the inner wall of the tube, portions of the oxide layer fall inside the 60A container.

The motor 38 continues to rotate, the test cutter actuator

52A moves the test cutter between its extended position and the retractor in a similar manner. However, since the roll of this actuator runs over the short portion 156 of the extension ramp 150, the circular arc defined by the test cutter 52^of, which moves against the surface of the inner wall of the tube is smaller than the arc defined by the 50A oxide cutter moving on the surface of the inner wall of the tube. Therefore, the sample portion is smaller than the oxide layer portion. As in the assembly cutter assembly 30, the sample cutter 52A also makes a narrow cut and deeper than the oxide cutter 50A. This is done by using blades (not shown) between the test cutter 52A and the drum 68A of the test cutter. The deeper, narrower and shorter cut made by the 50A test cutter ensures that the sample is free of oxide,

Λ- 2 Ο 1 1 - Ο 1 4 5 5 - 2 1 -05- 2010 thus ensuring ο reliable analysis of the deuterium concentration of the sample that can be used to determine the useful life of the pressure tube.

Once the sample has been cut by the test cutter 52A and the test cutter 52A has been held in its retracted position, the motor 38 is stopped. The tool 120 is then repositioned in the pressure tube to obtain a second sample from a different location. Once the tool 120 is repositioned, the engine 38 is started so that it continues to rotate the cutting assembly 130, which causes the oxide cutter 50B to cut another portion of the oxide and the sample cutter 52B to cut another sample in the same as described above with respect to 50A and 52A milling cutters. Therefore, the tool 120 advantageously allows two samples to be cut before the tool 120 is withdrawn inside the protective sleeve to transfer the samples to the balloons included in the means of transport, as this step must be done after each sample. cut with a tool 20.

While the milling cutters 50A, 50B, 52A, 52B move on the circumference of the inner wall of the tube, they are not affected by surface variations in the axial direction of the tube. Therefore, the tool 120 can be used to obtain samples in the region of the laminated connection in the pressure tube.

Modifications and improvements of the embodiments described above of the present invention may become apparent to those skilled in the art. The above description is intended to be exemplary rather than limiting. Therefore, the scope of the present invention is intended to be limited only by the appended claims.