JP2013079820A - Liquid metal loop and neutron generator - Google Patents

Abstract

[PROBLEMS] To use a large number of bellows 13 in a liquid metal loop, resulting in high costs.
The liquid metal loop includes a target forming unit that forms a target of a proton beam by injecting a liquid metal into a film between a nozzle and a receiving unit, and a loop that circulates the liquid metal. And a pipe 10 constituting the same. A part of the pipe 10 includes only the non-stretchable pipe 10 provided in parallel to the liquid metal injection direction. When the temperature rises during operation due to the irradiation of the proton beam and the pipe 10 is thermally stretched, the target forming unit 1 injects liquid metal into a film to form a target with a jet, so the nozzle 11 and the receiving unit There is no structure between the target forming portion 1 and the target forming portion 1 can absorb thermal expansion and contraction. For this reason, since it is not necessary to provide the bellows 13 in the piping 10 of the injection direction of a liquid metal, manufacturing cost can be reduced and maintenance work can be reduced.
[Selection] Figure 1

Description

  The present invention relates to a liquid metal loop and a neutron generator that circulates liquid metal in a loop by connecting a quench tank and a circulation pump by piping.

  FIG. 11 is a block diagram showing a conventional liquid metal loop. The liquid metal loop 900 includes a target 901 for irradiating a proton beam to obtain neutrons, a quench tank 902 disposed downstream of the target 901, a circulation pump 903 connected to the quench tank 902, and a circulation pump 903. And a heat exchanger 904 disposed on the downstream side. The target 901 is of a type in which liquid lithium is pressed against the curved back plate 905 by centrifugal force to form a liquid lithium film flow on the back plate 905.

  In the liquid metal loop 900, the target 901, the circulation pump 903, and the heat exchanger 904 are connected by a stainless steel pipe 906. The pipe 906 is provided with a bellows 907 in order to absorb expansion and contraction accompanying the rise in temperature of liquid lithium. The bellows 907 is provided in the direction in which each pipe 906 expands and contracts.

  When the operation of the liquid metal loop 900 is started, liquid lithium flows on the back plate 905, and a liquid lithium film flow is formed. When this liquid lithium is irradiated with a proton beam, the temperature of the liquid lithium rises and the temperature of the pipe 906 rises. The pipe 906 is thermally stretched due to a temperature rise, but the thermal elongation is absorbed by the bellows 907 provided in the laying direction of each pipe 906. In addition, as the conventional liquid metal loop 900, what was described in patent document 1 is known.

JP 2001-33600 A

  However, the conventional liquid metal loop 900 has a problem in that the cost of the entire apparatus increases because a large number of bellows 907 that absorb thermal expansion and contraction of the pipe 906 are provided in the pipe 906. In addition, since the life of the bellows 907 is relatively short, it is necessary to perform maintenance such as replacement. However, replacement and processing of the bellows 907 exposed to neutrons require much labor and cost, and the maintenance cost of the liquid metal loop 900 increases. There was a problem that it would end up. The present invention has been made to solve such problems.

  The liquid metal loop according to the first invention connects at least a quench tank and a circulation pump in a loop shape, and circulates the liquid metal, and injects the circulating liquid metal into a proton beam irradiation space in a film shape. And a target forming portion connected to the pipe, and a part of the pipe is parallel to the jet direction of the liquid metal. It is characterized by comprising only non-stretchable piping.

  The liquid metal loop constitutes a loop by connecting at least a quench tank and a circulation pump with piping. When a proton beam is irradiated onto a liquid metal target, the temperature of the circulating liquid metal rises, and the non-stretchable pipe is thermally stretched. This non-stretchable pipe means a normal pipe without a bellows. Here, the target forming unit forms a target by jetting a liquid metal into a proton beam irradiation space, and there is no structure between the nozzle and the receiving unit. The thermal expansion and contraction of the pipe can be absorbed with fluctuations in the distance from the section. For this reason, since it becomes unnecessary to provide a bellows in the piping in the liquid metal injection direction, the manufacturing cost can be reduced and the maintenance work can be reduced.

  The liquid metal loop according to the second invention connects at least the quench tank and the circulation pump in a loop shape, and circulates the liquid metal and injects the circulating liquid metal into the proton beam irradiation space in a film shape. And a target forming portion connected to the pipe, where the pipe is X: jet direction of the liquid metal, Y: It is arranged in the X, Y, and Z axial directions of the width direction of the receiving portion of the target forming portion, Z: the height direction of the receiving portion of the target forming portion, and at least biaxial piping among these is constituted only by the non-stretchable piping. The total amount of thermal expansion and contraction of the non-stretchable pipe is the dimension of the width W or height H of the receiving part of the target forming part and the film width Tw or film thickness Tt of the target to be formed. difference( -Tw, wherein the H-Tt) less than.

  Absorption of thermal expansion and contraction of the pipe in the X-axis direction (injection direction) is the same as described above. In the Y-axis and Z-axis directions, the receiving portion has dimensions larger than the target film width Tw and film thickness Tt, in other words, the total amount of thermal expansion / contraction of the non-stretchable pipe (the non-stretchable pipe in the pipe system The total amount of displacement from the fixed reference position) is the dimension of the width W or height H of the receiving part of the target forming part and the film width Tw or film thickness Tt of the target to be formed. By making it smaller than the difference (W−Tw, H−Tt), it becomes possible to absorb the thermal elongation in the film width Tw or film thickness Tt direction. That is, even if the relative position between the nozzle and the receiving portion is shifted in the Y or Z axis direction, the receiving portion can receive the jet of liquid lithium, and the target is maintained.

  A liquid metal loop according to a third aspect of the present invention includes a pipe that connects at least a quench tank and a circulation pump in a loop shape, circulates the liquid metal, and a flow path portion that is continuously formed in a back wall that forms a film flow of the liquid metal. And a target forming part slidably inserted into a pipe provided in the liquid metal inlet of the quench tank and connected to the pipe, and the pipe in a direction parallel to the flow path part is not It is characterized by comprising only stretchable piping.

  That is, since the quench tank piping and the flow path portion of the target forming portion are slidably inserted, thermal expansion and contraction of the non-stretchable piping can be absorbed. For this reason, since it is not necessary to provide a bellows in the pipe in the liquid metal injection direction, the manufacturing cost can be reduced and the maintenance work can be reduced.

  The liquid metal loop according to a fourth aspect of the present invention is characterized in that, in the above-described invention, the liquid metal loop further includes slide support means for sliding in the heat expansion / contraction direction in a state where the pipe is supported.

  The liquid metal loop according to a fifth aspect of the present invention is characterized in that, in the above invention, the slide support means has a structure that can slide in two axial directions in the XYZ axial directions.

  In the liquid metal loop according to a sixth aspect of the present invention, in the above invention, the slide support means further converts a slide amount due to thermal expansion / contraction in one axial direction into a slide amount corresponding to expansion / contraction in the other axial direction. Features.

  A neutron generator according to a seventh invention has the liquid metal loop described in any one of the above.

It is a block diagram which shows the liquid metal loop concerning Embodiment 1 of this invention. It is a block diagram which shows the liquid metal loop concerning Embodiment 1 of this invention. It is explanatory drawing which shows the structural example of the slide support part of the liquid metal loop shown in FIG. It is explanatory drawing which shows the dimensional relationship between a nozzle and a target. It is a block diagram which shows the liquid metal loop concerning Embodiment 1 of this invention. It is explanatory drawing which shows the structural example of the slide support part of the liquid metal loop shown in FIG. It is explanatory drawing which shows an example of the slide support part used for the liquid metal loop concerning Embodiment 4 of this invention. It is explanatory drawing which shows the slide support part in the case of suspending piping from a ceiling or a beam. It is a block diagram which shows another example of a slide support part. It is a block diagram which shows a part of liquid metal loop based on Embodiment 5 of this invention. It is a block diagram which shows the conventional liquid metal loop.

(Embodiment 1)
FIG. 1 is a configuration diagram showing a liquid metal loop according to a first embodiment of the present invention. The liquid metal loop 100 includes a target forming unit 1 for forming a liquid lithium target T, a quench tank 2 connected from the target forming unit 1 through a pipe 10, and a circulation connected to the pipe 10 extending from the quench tank 2. It has the pump 3 and the heat exchanger 4 connected to the piping 10 extended from the circulation pump 3, and the piping 10 extended from the heat exchanger 4 is connected to the target formation part 1 again.

  The target forming unit 1 includes a nozzle 11 that ejects liquid lithium in a plane so as to cross the proton beam irradiation region, and a receiving unit 12 that receives the ejected liquid lithium. The nozzle 11 has a strip-shaped discharge port formed at the tip. The liquid lithium ejected from the discharge port at a high pressure becomes a film-like jet. The liquid lithium that has become a jet is buffered by the receiving portion 12.

The arrangement direction of the pipes 10 constituting the liquid metal loop 100 is divided as follows.
X: injection direction of the liquid lithium Y: width direction of the receiving portion 12 of the target forming portion 1 Z: height direction of the receiving portion 12 of the target forming portion 1

  The X-axis direction is the liquid lithium injection direction of the target forming unit 1, and the pipe 10x disposed in the X-axis direction is configured by only non-stretchable pipes. The non-stretchable pipe refers to the pipe 10 that does not have the bellows 13, and includes a connecting pipe that connects the pipes. The stretchable pipe refers to a pipe in which a bellows 13 is provided on the pipe 10 to absorb thermal expansion and contraction, and includes a normal pipe 10 connected to the stretchable pipe.

  The pipes 10y and 10z in the Y-axis direction and the Z-axis direction are constituted by stretchable pipes.

  The nozzle 11 of the target forming unit 1 is supported by a slide support unit 20. The thermal expansion and contraction of the pipe 10 in the usage state of the liquid metal loop 100 is in the range of about 3 mm to 10 mm depending on the scale such as the length. For this reason, the slide support part 20 should just slide-support the target formation part 1 in the injection direction of liquid lithium in the said range. For example, the slide support unit 20 may have a structure in which the nozzle 11 can be installed on a column placed on a bed having a sliding surface. Further, a structure may be adopted in which the column is supported by a linear guide provided on the bed so that the column can be moved directly, and the nozzle 11 can be installed on the column. In addition to these, a known structure that can support the nozzle 11 so as to be linearly movable can be adopted. The receiving part 12 of the target forming part 1 can also be supported by the same slide support part 20 as described above.

  The heat exchanger 4 is also supported by a slide support portion 21 similar to the slide support portion 20. In addition, the slide support part 22 that supports the pipe 10 is a support means having a simple structure capable of absorbing thermal expansion and contraction (an example of the slide support part 22 will be described later).

  Next, the movement of the liquid metal loop 100 will be described. By operating the circulation pump 3 and supplying liquid lithium to the nozzle 11 of the target forming unit 1, liquid lithium is ejected from the nozzle 11 into a film shape. When this film-like liquid lithium target T is irradiated with a proton beam, neutrons are generated behind it. Since the liquid lithium heated by the irradiation of the proton beam enters from the receiving portion 12 and circulates in the pipe 10, the temperature of the pipe 10 gradually increases after the start of operation, and the pipe 10 causes thermal expansion.

  In the pipe 10x in the X-axis direction, since the pipe 10x is configured by a non-stretchable pipe, the target forming unit 1 slightly moves according to the thermal elongation of the pipe 10x. Since the nozzle 11 and the receiving part 12 are supported by the slide support part 20 so as to be slidable finely, the target forming part 1 moves according to the thermal elongation of the pipe 10x. Here, the target forming unit 1 forms a target T by blowing a jet of liquid lithium between the nozzle 11 and the receiving unit 12, and forms a liquid film on a curved back wall as in the prior art. Therefore, there is no structure between the nozzle 11 and the receiving portion 12.

  For this reason, even if the interval between the nozzle 11 and the receiving portion 12 changes minutely, there is no problem as long as the proton beam irradiation range does not change. Therefore, the length of the pipe 10x between the receiving part 12 and the quench tank 2 in the X-axis direction is different from the length of the pipe 10x between the nozzle 11 and the heat exchanger 4, and as a result, the nozzle 11 and the receiving part 12 Even if the amount of movement is different, the amount of movement can be absorbed by the target forming unit 1. The heat exchanger 4 also slides by the slide support portion 21 in accordance with the thermal elongation of the pipe 10x in the X-axis direction and absorbs the thermal elongation.

  Even when the pipe 10x between the receiving portion 12 and the quench tank 2 is an elastic pipe, the nozzle 11 moves and absorbs the thermal expansion and contraction between the nozzle 11 and the heat exchanger 4. On the other hand, even when the pipe 10x between the nozzle 11 and the heat exchanger 4 is an elastic pipe, the receiving part 12 moves to absorb the thermal expansion and contraction between the receiving part 12 and the quench tank 2.

  On the other hand, since the pipes 10y and 10z in the Y-axis direction and the Z-axis direction are constituted by stretchable pipes, the thermal expansion and contraction is absorbed by the bellows 13 provided in the stretchable pipes.

  As described above, according to the liquid metal loop 100 of the present invention, the pipe 10x parallel to the X-axis direction (liquid lithium injection direction) is a non-stretchable pipe, and the thermal expansion of the non-stretchable pipe is caused by the target forming unit 1. Since it absorbs, the number of bellows 13 can be decreased. For this reason, the cost of the liquid metal loop 100 can be reduced. In addition, the bellows 13 needs to be periodically replaced to maintain performance, and liquid lithium exposed to neutrons circulates internally. By reducing the number of such bellows 13, the maintenance work is simplified, and the maintenance cost of the liquid metal loop 100 can be reduced.

  In addition, ordinary large liquid metal loops are designed to absorb thermal expansion by taking a large number of bends in the pipes that make up the loops. Absorption is difficult. The liquid metal loop 100 of the present invention is suitable for the structure of a liquid metal loop with little bending and a short pipe length.

(Embodiment 2)
FIG. 2 is a block diagram showing a liquid metal loop according to Embodiment 2 of the present invention. The liquid metal loop 200 is characterized in that, in the liquid metal loop 100 of the first embodiment, the thermal elongation of the pipe 10z in the Z-axis direction is further absorbed. Since other configurations are the same as those of the first embodiment, the description thereof is omitted, and the same reference numerals are given to the same components.

  In the liquid metal loop 200, the pipes 10x and 10z arranged in the X-axis direction and the Z-axis direction are configured by only non-stretchable pipes. Moreover, the receiving part 12 of the target forming part 1 has a height H (length in the short side direction) larger than the film thickness Tt of the target T formed as a film-like jet as shown in FIG. The total amount of thermal expansion and contraction of the non-stretchable pipe in the Z-axis direction (the total amount of displacement from the reference position where the non-stretchable pipe in the piping system is fixed) is received by the target forming unit 1. It is assumed that the difference between the dimension of the height H of the portion 12 and the dimension of the film thickness Tt of the target T to be formed is smaller. Preferably, it is less than half the difference in dimensions. For example, when the quench tank 2 has a fixed structure, the fixed reference position is a fixed position of the non-stretchable pipe of the quench tank 2 in the Z-axis direction.

  The nozzle 11 and the receiving part 12 are preferably supported by a slide support part 23. The slide support portion 23 used in the liquid metal loop 200 is configured to move up and down according to the movement in the X-axis direction so that it can be supported even if the nozzle 11 or the receiving portion 12 moves in the Z-axis direction. In other words, the slide amount due to thermal expansion and contraction in the X-axis direction is converted into a slide amount corresponding to expansion and contraction in the Z-axis direction. FIGS. 4A and 4B are explanatory views showing such a slide support portion, in which FIG. 4A shows a state before operation of the liquid metal loop, and FIG. 4B shows a state during operation. The slide support 23 can be realized by installing the nozzle 11 on a column 232 placed on a bed 231 having a sliding surface and setting the bed 231 at a predetermined angle.

  In configuring the slide support portion 23, a thermal elongation amount corresponding to the temperature in the X-axis direction and a thermal elongation amount of the pipe 10z in the Z-axis direction corresponding to the temperature are obtained, and the X-axis direction and the Z-axis direction are determined. The relationship between the amount of thermal elongation and Then, the amount of movement in the Z-axis direction is determined relative to the movement in the X-axis direction, and the upper surface of the bed 231 is tilted. Then, with the horizontal movement in the X-axis direction due to the temperature rise, the column 232 moves up and down (Δz) by a predetermined amount in the Z-axis direction, and the nozzle 11 or the receiving part 12 even if there is a biaxial displacement in the XZ direction. Can be supported. As described above, the slide support portion 23 is not limited to such a configuration as long as the column can move up and down by a predetermined amount in the Z-axis direction along with the horizontal movement in the X-axis direction due to the temperature rise.

  In the liquid metal loop 200, the behavior related to the thermal elongation of the pipe 10x in the X-axis direction is the same as that in the first embodiment. In the thermal elongation of the pipe 10z in the Z-axis direction, the target forming unit 1 slightly moves according to the thermal elongation of the pipe 10 because the pipe 10z is formed of a non-stretchable pipe as described above. The target forming unit 1 also moves in the Z-axis direction by moving the nozzle 11 or the receiving unit 12 based on expansion and contraction in the X-axis direction. This movement amount is an amount corresponding to the thermal elongation of the pipe 10z in the Z-axis direction.

  As a result of the difference in the length of the pipe 10z between the receiving part 12 and the quench tank 2 in the Z-axis direction and the length of the pipe 10z between the nozzle 11 and the heat exchanger 4, the nozzle 11 and the receiving part 12 The amount of movement is different. Here, the total amount of thermal expansion and contraction of the non-stretchable pipe in the Z-axis direction is the dimension of the height H of the receiving part 12 of the target forming part 1 and the film thickness Tt of the target to be formed. Since it is set smaller than the difference, thermal expansion and contraction in the Z-axis direction can be absorbed by the target forming unit 1. That is, even when the relative position between the nozzle 11 and the receiving portion 12 is shifted in the Z-axis direction, the receiving portion 12 can receive a jet of liquid lithium, and the target T can be maintained.

  Further, since the nozzle 11 and the receiving portion 12 are supported by the slide support portion 23 and move up and down in the Z-axis direction in response to thermal expansion in the X-axis direction, the nozzle 11 and the receiving portion described above. The amount of deviation in the Z-axis direction relative to the position 12 can be kept small.

  According to the liquid metal loop 200 described above, the pipes 10x and 10z in the X-axis direction and the Z-axis direction are non-stretchable pipes, and the thermal elongation of the non-stretchable pipes is absorbed by the target forming unit 1. The number can be reduced. For this reason, the cost of the liquid metal loop 200 can be significantly reduced. Further, since the number of bellows 13 is significantly reduced, the maintenance work is simplified, and the maintenance cost can be greatly reduced.

(Embodiment 3)
FIG. 5 is a block diagram showing a liquid metal loop according to Embodiment 3 of the present invention. The liquid metal loop 300 is characterized in that, in the liquid metal loop 200 of the second embodiment, the thermal elongation of the pipe 10y in the Y-axis direction is further absorbed. Since other configurations are the same as those of the second embodiment, the description thereof is omitted, and the same components are denoted by the same reference numerals.

  In the liquid metal loop 300, the pipes 10x, 10y, and 10z arranged in the XYZ axial directions are configured only by non-stretchable pipes. Moreover, the receiving part 12 of the target forming part 1 has a width (length in the long side direction) larger than the film width Tw of the target T formed as a film-like jet. The total amount of thermal expansion / contraction of the non-stretchable pipe in the Y-axis direction (the total amount of displacement from the reference position where the non-stretchable pipe in the pipe system is fixed) is received by the target forming unit 1. It is assumed that it is smaller than the difference between the dimension of the width W of the portion 12 and the film width Tw of the target T to be formed. Preferably, it is less than half the difference in dimensions. For example, when the quench tank 2 has a fixed structure, the fixed reference position is a fixed position of the non-stretchable pipe of the quench tank 2 in the Y-axis direction.

  It is preferable to use the slide support 24 as shown in FIG. The slide support portion 24 is moved to the column 232 of the slide support portion 231 in FIG. 6 so as to support the nozzle 11 or the receiving portion 12 even if the nozzle 11 or the receiving portion 12 moves in the Y-axis direction (X-axis direction). ), A second column 233 that can move in a direction (Y-axis direction) perpendicular to ().

  In this liquid metal loop 300, the behavior related to the thermal elongation of the pipes 10x and 10z in the X-axis direction and the Z-axis direction is the same as that in the second embodiment. In the thermal expansion of the pipe 10y in the Y-axis direction, since the pipe 10 is formed of a non-stretchable pipe as described above, the target forming unit 1 moves slightly according to the thermal expansion of the pipe 10.

  As a result of the difference in the length of the pipe 10y between the receiving part 12 and the quench tank 2 in the Y-axis direction and the length of the pipe 10y between the nozzle 11 and the heat exchanger 4, the nozzle 11 and the receiving part 12 The amount of movement will be different. Here, the total amount of thermal expansion and contraction of the non-stretchable pipe in the Y-axis direction is based on the difference in dimension between the width W of the receiving part 12 of the target forming part 1 and the film width Tw of the target to be formed. Since it is set to be small, thermal expansion and contraction in the Y-axis direction can be absorbed by the target forming unit 1. That is, even if the relative position between the nozzle 11 and the receiving portion 12 is shifted in the Y-axis direction, the receiving portion 12 can receive a jet of liquid lithium, and the target can be maintained.

  According to the liquid metal loop 300 described above, the pipe 10 in the XYZ axial directions is a non-stretchable pipe, and the thermal elongation of the non-stretchable pipe is absorbed by the target forming unit 1, so that the number of bellows 13 is significantly reduced. it can. For this reason, the cost of the liquid metal loop 300 can be significantly reduced. Further, since the number of bellows 13 is significantly reduced, the maintenance work is simplified and the maintenance cost can be reduced.

  In the first to third embodiments, for convenience of explanation, the quench tank 2 is arranged on the pipe 10z, the circulation pump 3 is arranged on the pipe 10y, and the heat exchanger 4 is arranged on the pipe 10x. However, the present invention is not limited to this. In addition, the pipe 10 is often arranged substantially in the XYZ axis direction, but not all the pipes are arranged in the XYZ axis direction. In that case, each piping 10 is decomposed | disassembled into the component of an XYZ axial direction, and the said embodiment shall be applied. In an actual liquid metal loop, a large structure such as the quench tank 2 is fixed. For example, when the quench tank 2 and the circulation pump 3 have a fixed structure, a bellows 13 may be provided in the pipe 10 therebetween.

(Embodiment 4)
FIGS. 7A and 7B are explanatory views showing an example of a slide support portion used in the liquid metal loop according to the fourth embodiment of the present invention. FIG. 7A is a radial sectional view of the pipe, and FIG. 7B is an axial view of the pipe. It is a side view. The slide support portion 22 supports the pipe 10, a grip portion 221 having a structure in which a cylindrical body that grips the pipe 10 is divided in the axial direction, a support plate 222 that supports the grip portion 221, and a support plate The slide plate 223 is provided at a lower portion of 222, and a guide portion 224 that linearly guides the slide plate 223. When the pipe 10 undergoes thermal elongation, the grip portion 221 slides along the guide portion 224 together with the slide plate 223. For this reason, the piping 10 which heat-extends can be supported, sliding.

  Moreover, FIG. 8 is explanatory drawing which shows the slide support part in the case of suspending piping from a ceiling or a beam. The slide support portion 26 suspends and supports the pipe 10, a grip portion 261 having a structure in which a cylindrical body that grips the pipe 10 is divided in the axial direction, a support rod 262 that supports the grip portion 261, A spring hanger 263 that moves up and down and rotates in the axial direction of the pipe 10 is provided at the upper end of the support bar 262. When the pipe 10 undergoes thermal elongation, the gripping portion 261 moves, and this movement is absorbed by the spring hanger 263. Further, when the pipe 10 moves up and down in the vertical direction, the spring hanger 263 can absorb the up and down movement. Further, the spring hanger 263 is pivotally supported on the ceiling or the beam by a shaft support portion 264 so as to be rotatable. As described above, the slide support portion 26 can be slid in the three-axis directions, and therefore can be used as the slide support portions 22 and 23 in the second and third embodiments.

  FIG. 9 is a configuration diagram illustrating another example of the slide support portion, in which (a) is a side view in the axial direction of the pipe, and (b) is a radial cross-sectional view of the pipe. The slide support portion 27 includes a first magnet 271 obtained by dividing a cylindrical body facing the periphery of the pipe 10 in the axial direction and a cylindrical body that generates a magnetic force repelling the first magnet 271 in the axial direction. The divided second magnet 272, the cylindrical support portion main body 273 provided with the second magnet 272 on the inner surface, the support portion 274 supporting the support portion main body 273, and the movement amount restricting portion provided in a part of the pipe 10 275. The pipe 10 passes through the center of the slide support 27 in the axial direction. The first magnet 271 and the second magnet 272 are permanent magnets, but either one or both may be electromagnets.

  The pipe 10 is supported in a floating state by a repulsive force generated between the first magnet 271 and the second magnet 272. When the pipe 10 undergoes thermal elongation in this state, the pipe 10 moves in the axial direction while being supported by a magnetic force. In the case of such a slide support part 27, the pipe 10 is supported by magnetic force, so that the heat of the pipe 10 can be blocked by the slide support part 27. Further, the first magnet 271 and the second magnet 272 can be moved minutely in the three-axis directions by the gap between them. For this reason, it can be used as the slide support portions 20, 22, and 23 in the first to third embodiments.

(Embodiment 5)
FIG. 10 is a configuration diagram showing a part of a liquid metal loop according to Embodiment 5 of the present invention. The liquid metal loop 500 is different from the first to fourth embodiments in that the liquid metal loop 500 is configured to form a liquid metal film flow on the back wall. Since other configurations are the same as those of the first to fourth embodiments, description thereof is omitted. The back wall 15 of the target forming unit 501 may be planar or curved. A substantially linear flow path portion 16 continuously formed from the back wall 15 is slidably inserted into a pipe 17 provided on the side surface of the tank body of the quench tank 2. The pipe 17 is provided at the liquid metal inlet 18 of the quench tank 2.

  The target forming portion 501 is slidably supported by slide support portions 20, 22, and 23. The pipe 10x in the X-axis direction parallel to the flow path portion 16 is composed of a non-stretchable pipe.

  The liquid metal flowed on the back wall 15 reaches the pipe 17 from the flow path portion 16 and is introduced into the quench tank 2. Further, by irradiating the target with a proton beam, the temperature of the liquid metal in the pipe 10 rises, and the pipe 10 is thermally expanded. The target forming portion 501 moves due to this thermal elongation, and the amount of movement is absorbed between the flow path portion 16 and the pipe 17. In this way, since the pipe 10x that is parallel to the flow path portion 16 can be configured by only the non-stretchable pipe, the number of bellows 13 on the loop can be reduced, and the cost can be reduced.

  In the case where the Y and Z directions are composed only of non-stretchable pipes, the gap between the flow path portion 16 and the pipe 17 is larger than the elongation in the Y-axis direction and the Z-axis direction. And the thermal elongation in the Z-axis direction can be absorbed.

  Further, the neutron generator configured using the liquid metal loops 100 to 500 has a simple piping 10 structure and low maintenance costs.

DESCRIPTION OF SYMBOLS 100 Liquid metal loop 1 Target formation part 2 Quench tank 3 Circulation pump 4 Heat exchanger 10 Piping 11 Nozzle 12 Receiving part 20 Slide support part

Claims (7)

A pipe connecting at least a quench tank and a circulation pump in a loop to circulate liquid metal;
A target forming unit comprising a nozzle and a receiving part for forming a target by injecting a circulating liquid metal into a proton beam irradiation space in a film, and the nozzle and the receiving part connected to the pipe; Have
A part of said piping is provided in parallel with the injection direction of said liquid metal, and is comprised only from non-stretchable piping, The liquid metal loop characterized by the above-mentioned. A pipe connecting at least a quench tank and a circulation pump in a loop to circulate liquid metal;
A target forming unit comprising a nozzle and a receiving part for forming a target by injecting a circulating liquid metal into a proton beam irradiation space in a film, and the nozzle and the receiving part connected to the pipe; Have
The piping is
X: injection direction of the liquid metal Y: width direction of the receiving part of the target forming part Z: arranged in the XYZ axial direction of the height part of the receiving part of the target forming part Consists of non-stretchable piping only,
The total amount of thermal expansion and contraction of the non-stretchable pipe is smaller than the difference in dimension between the width or height of the receiving part of the target forming part and the film width or film thickness of the target to be formed. Features a liquid metal loop. A pipe connecting at least a quench tank and a circulation pump in a loop to circulate liquid metal;
A flow path portion formed continuously on the back wall for forming a liquid metal film flow is slidably inserted into a pipe provided at the liquid metal inlet of the quench tank and connected to the pipe. And having
A liquid metal loop, wherein a pipe in a direction parallel to the flow path portion is composed of only a non-stretchable pipe. Furthermore, the liquid metal loop as described in any one of Claims 1-3 provided with the slide support means to slide to a thermal expansion-contraction direction in the state which supported the said piping. 5. The liquid metal loop according to claim 4, wherein the slide support means is configured to be slidable in two of the XYZ axial directions. 6. The liquid metal loop according to claim 5, wherein the slide support means converts a slide amount due to thermal expansion and contraction in one axial direction into a slide amount corresponding to expansion and contraction in another axial direction. A neutron generator comprising the liquid metal loop according to claim 1.

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