JP2019219223A - Reactor and nuclear power plant - Google Patents

Abstract

To provide a reactor capable of improving the output of the reactor by preventing uneven temperature distribution of the moderator.SOLUTION: The reactor is constituted of a plurality of fuels 14 containing a fissile material and a plurality of moderator materials 15 for slowing down neutrons, which are formed in an annular shape and arranged alternately; and a plurality of heat pipes 16 for transporting the heat generated by the fission reaction of the fuels 14, which is formed in an annular shape and arranged between the fuels 14 and the moderator materials 15. Within the heat pipes, a separator panel is form in an annular shape for separating the up-flow and down-flow of a working fluid is disposed.SELECTED DRAWING: Figure 2

Description

  An embodiment of the present invention relates to a nuclear reactor having a heat pipe and a nuclear power plant having the nuclear reactor.

  The application of small nuclear reactors has been considered as a power source for bases built on the surface of the moon or Mars, or as a distributed power source in areas such as remote islands with low population on the ground. In the installation place as described above, it is considered to avoid using a general pump as a coolant circulation method in order to minimize the need for human intervention. Therefore, application of a heat pipe as a heat transport device that cools a heating element by using heat of vaporization of a working fluid is considered.

  As shown in FIG. 11, a nuclear power plant 100 including a nuclear reactor 101 described in Non-Patent Document 1 described above includes a nuclear reactor 101 having nuclear fuel and a plurality of nuclear reactors for transporting heat generated by a nuclear fission reaction of nuclear fuel. , A thermoelectric element 103 that converts heat transferred by the heat pipe 102 into electricity and generates power, and a radiating panel 104 that radiates heat generated by the power generation.

  In the nuclear reactor 101, as shown in FIG. 12, a control rod 105 is disposed at a central portion, and around the control rod 105, a fuel 106 and a moderator 107 are both formed in a ring shape and arranged alternately. In 106, a plurality of heat pipes 102 having a double pipe structure are arranged in the circumferential direction of the reactor 101. However, in such a reactor 101, the temperature distribution of the moderator 107 is biased, and the temperature distribution of the moderator 107 exceeds the required temperature (for example, a temperature range in which hydrogen is not dissociated when the moderator 107 is a metal hydride). Could be.

  In order to avoid the above-described situation, a nuclear reactor is disclosed in which the enrichment of the fuel in the nuclear reactor is made different, and the enrichment is set lower for fuels farther from the heat pipe to flatten the temperature distribution of the moderator. ing.

JP 2018-21763 A

Kimura et al., "Development of Reactor System for Small Distributed Power Source 1) Reactor System and Core Concept for Lunar and Mars Missions," Atomic Energy Society of Japan, 2016 Fall Conference 3I08, 2016. Kimura et al. , "Small CaH2 moderated thermal reactor for surface power generation 1): Conceptual design," Transactions of the 2016 ANS Winter Meeting, 20 ANS Winter Meeting.

  However, even in the above-mentioned nuclear reactor, there may be a portion where the amount of heat flowing into the heat pipe becomes excessively large, and the temperature of the moderator may not always be sufficient with respect to the required temperature value.

  An embodiment of the present invention has been made in view of the above circumstances, and provides a nuclear reactor and a nuclear power plant that can prevent the temperature distribution of the moderator from being biased and improve the output of the nuclear reactor. The purpose is to:

  In the nuclear reactor according to the embodiment of the present invention, the fuel containing the fissile material and the moderator for moderating neutrons are formed in an annular shape and arranged alternately, and the heat pipe transports heat generated by the nuclear fission reaction of the fuel. Are formed annularly and arranged between the fuel and the moderator.

  A nuclear power generation device according to an embodiment of the present invention is a power generation device that is installed in a reactor described in the invention and a part of a heat pipe extending outside the reactor, and converts heat generated in the reactor into electricity. And a heat radiating portion that radiates heat to the outside at a downstream side of the power generation portion in the heat pipe.

  ADVANTAGE OF THE INVENTION According to embodiment of this invention, the bias of the temperature distribution of a moderator can be prevented and the output of a nuclear reactor can be improved.

FIG. 2 is a longitudinal sectional view showing the nuclear power plant according to the first embodiment. FIG. 2 is a cross-sectional view showing the reactor of FIG. 1. FIG. 3 is a longitudinal sectional view showing a part III of the reactor shown in FIG. 2. FIG. 2 is a longitudinal sectional view showing a part of a power generation unit and a heat radiation unit of FIG. 1. FIG. 4 is a cross-sectional view showing a nuclear reactor of a nuclear power plant according to a second embodiment. The longitudinal section showing the nuclear power plant concerning a 3rd embodiment. The partial perspective view showing the nuclear power plant concerning a 4th embodiment. The nuclear power generator concerning 5th Embodiment is shown, (A) is a partial perspective view of the whole structure, (B) is a longitudinal cross-sectional view which shows the heat pipe and heat radiation part of FIG. 8 (A). The schematic longitudinal section showing the nuclear power plant concerning a 6th embodiment. FIG. 16 is a schematic longitudinal sectional view showing a comparative example of the sixth embodiment. The block diagram which shows the conventional nuclear power plant. 12A is a cross-sectional view, and FIG. 12B is a partial cross-sectional view of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[A] First Embodiment (FIGS. 1 to 4)
FIG. 1 is a longitudinal sectional view showing the nuclear power plant according to the first embodiment. The nuclear power generator 10 shown in FIG. 1 is used for power generation not only in outer space, the moon, the surface of Mars, etc., but also in polar regions on the earth. It is composed.

  As shown in FIGS. 1 to 3, the nuclear reactor 11 includes a plurality of fuels 14 containing fissile material and moderators 15 for moderating neutrons, which are formed in an annular shape and are alternately arranged. A plurality of annular heat pipes 16 are arranged between the moderator 15 and the moderator 15. Further, an annular reflector 17 is arranged at the outermost peripheral position of the reactor 11, and a control rod 18 is arranged at a central position of the reactor 11.

The control rod 18 controls the fission reaction of the fuel 14. Further, the moderator 15 promotes the fission reaction of the fuel 14 by slowing down the neutrons. This moderator 15 is made of, for example, a metal hydride such as CaH ₂ . Further, the reflector 17 reflects neutrons that are about to fly out of the reactor 11 toward the center of the reactor 11.

  The heat pipe 16 transports heat generated by the nuclear fission reaction of the fuel 14 to the power generation unit 12 by evaporating and condensing the working fluid. An annular separation plate 19 for separating the upward flow A and the downward flow B of the working fluid is disposed in the heat pipe 16. The separation pipe 19 divides the heat pipe 16 into an upward flow path 16A through which the upward flow A of the working fluid flows and a downward flow path 16B through which the downward flow B of the working fluid flows.

  The power generation unit 12 shown in FIGS. 1 and 4 is installed in a part of an annular heat pipe 16 extending outside the reactor 11, that is, in an ascending flow path 16 </ b> A of the heat pipe 16. The power generation unit 12 may be formed integrally along the circumferential direction of the annular heat pipe 16, or may be configured by arranging a plurality of power generating units 12 along the circumferential direction of the heat pipe 16. The power generation unit 12 includes a thermoelectric element, and converts heat generated in the fuel 14 of the nuclear reactor 11 into electricity to generate power. Although FIG. 1 shows only the power generation unit 12 installed on the annular heat pipe 16 arranged at the outermost position in the nuclear reactor 11, this power generation unit 12 includes all the heat pipes in the nuclear reactor 11. 16 installed.

  The heat radiating unit 13 is configured as a downstream portion of the heat pipe 16 with respect to the power generation unit 12, and radiates heat provided for power generation by the power generation unit 12 to the outside. As shown in FIGS. 1 and 4, the heat radiating portion 13 is formed in a trumpet shape (substantially conical surface shape), but may be a cylindrical shape such as a cylinder. The heat radiating section 13 is a part of the heat pipe 16, and the ascending flow path 13 A communicates with the ascending flow path 16 A of the heat pipe 16, and the ascending flow path 13 B communicates with the descending flow path 16 B of the heat pipe 16. Are formed respectively.

  Although FIG. 1 shows only the heat radiating portion 13 that is continuous with the annular heat pipe 16 disposed at the outermost peripheral position in the nuclear reactor 11, the heat radiating portion 13 is provided to all the heat pipes 16 in the nuclear reactor 11. It is formed continuously.

  According to the first embodiment, the following advantages (1) and (2) can be obtained.

  (1) In the nuclear reactor 11 of the nuclear power plant 10, the fuel 14, the moderator 15, and the heat pipe 16 are formed in an annular shape, and the heat pipe 16 is arranged between the fuel 14 and the moderator 15 which are arranged alternately. As a result, the heat generated in the fuel 14 is evenly transmitted to the heat pipe 16 and further uniformly transmitted from the heat pipe 16 to the moderator 15, so that the bias of the temperature distribution in the moderator 15 can be prevented. . Therefore, the output of the reactor 11 is suppressed so that the moderator 15 does not exceed the required temperature value (for example, a temperature range in which the hydrogen of the moderator 15 composed of metal hydride does not dissociate) due to the uneven temperature distribution. Therefore, the output of the nuclear reactor 11 can be improved.

  (2) In the nuclear reactor 11, as described above, the fuel 14, the moderator 15 and the heat pipe 16 are formed in an annular shape, and the heat pipe 16 is disposed between the fuel 14 and the moderator 15 to generate the fuel 14. The generated heat is evenly transmitted to the heat pipe 16. For this reason, the temperature rise does not occur in the ascending flow A and the descending flow B of the working fluid flowing in the heat pipe 16, so that the power generation efficiency of the power generation unit 12 can be improved.

[B] Second embodiment (FIG. 5)
FIG. 5 is a cross-sectional view illustrating a nuclear reactor of a nuclear power plant according to the second embodiment. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is simplified or omitted.

  The nuclear power plant 20 of the second embodiment is different from the first embodiment in that the fuel 14, the moderator 15, and the heat pipe 16 in the reactor 21 constituting the nuclear power plant 20 are divided in their circumferential direction. This is the point that is configured.

  That is, the fuel 14, the moderator 15, and the heat pipe 16 are formed in an annular shape, and are divided into a plurality (for example, divided into quarters) in a circumferential direction thereof. Reference numeral 22 in FIG. 5 indicates a division surface of the fuel 14, the moderator 15, and the heat pipe 16. Accordingly, the reactor 21 includes the fuel sectors 14W, 14X, 14Y and 14Z of the fuel 14 divided by the division surface 22, the moderator sectors 15W, 15X, 15Y and 15Z of the moderator 15, and the heat pipe of the heat pipe 16. The sectors 16W, 16X, 16Y and 16Z are assembled and assembled.

  With the configuration described above, according to the second embodiment, the following effects (3) are obtained in addition to the effects (1) and (2) of the first embodiment.

  (3) Since the fuel 14, the moderator 15, and the heat pipe 16 of the reactor 21 are divided into a plurality of parts, the design and manufacture of the reactor 21 can be simplified.

[C] Third Embodiment (FIG. 6)
FIG. 6 is a longitudinal sectional view showing a nuclear power plant according to the third embodiment. In the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is simplified or omitted.

  The nuclear power generator 30 of the third embodiment is different from the first embodiment in that the heat radiating portion 31 of the nuclear power generator 30 is divided in the circumferential direction.

  That is, the heat radiating portion 31 is formed in an annular shape, but is divided into a plurality in the circumferential direction, and the divided heat radiating portion sectors 31A, 31B, 31C... Function independently. In FIG. 6, the division surface of the heat radiating portion 31 is indicated by reference numeral 32.

  With the configuration described above, according to the third embodiment, in addition to the effects (1) and (2) of the first embodiment, the following effect (4) is obtained.

  (4) Since the heat radiating section 31 is divided into a plurality of parts, the design and manufacturing of the heat radiating section 31 can be facilitated. When a part of the heat radiating sectors 31A, 31B, 31C... Loses the heat radiating function, the other heat radiating sectors 31A, 31B, 31C. Can be satisfactorily secured.

[D] Fourth Embodiment (FIG. 7)
FIG. 7 is a partial perspective view showing a nuclear power plant according to the fourth embodiment. In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is simplified or omitted.

  The nuclear power generator 40 of the fourth embodiment is different from that of the first embodiment in that, of the portions of the heat pipe 41 that extend outside the reactor 11, the upstream heat pipe portion 41A is different from the heat pipe 16 of the first embodiment. It is annular in the same manner as described above, except that a plurality of downstream heat pipe portions 16B are formed in a tubular shape. The heat radiating portion 42 is provided continuously at the tip of the downstream heat pipe portion 16B.

  With the configuration described above, according to the fourth embodiment, in addition to the effects (1) and (2) of the first embodiment, the following effect (5) is also obtained.

  (5) Among the portions of the heat pipe 16 that extend outside the reactor 11, the downstream heat pipe portion 41B is formed in a tubular shape, and has a higher strength than the upstream heat pipe portion 41A. As a result, the configuration of the heat pipe 41 can be simplified, and the structural strength can be increased.

[E] Fifth Embodiment (FIG. 8)
8A and 8B show a nuclear power plant according to a fifth embodiment, in which FIG. 8A is a partial perspective view of the entire configuration, and FIG. 8B is a longitudinal sectional view showing a heat pipe and a heat radiating section in FIG. In the fifth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is simplified or omitted.

  The nuclear power generation device 50 of the fifth embodiment is different from that of the first embodiment in that, of the portions of the heat pipe 51 extending outside the reactor 11, the upstream heat pipe portion 51A is connected to the heat pipe 16 of the first embodiment. A plurality of downstream heat pipe portions 51B are formed in a tubular shape, and a plurality of the downstream heat pipe portions 51B are provided with a heat radiating portion 52 continuously, and the downstream heat pipe portion 51B is raised. This is a point configured to include the flow path 53 and the descending flow path 54.

  That is, the upflow A of the working fluid flows through the upflow channel 53 of the downstream heat pipe portion 51B formed in a tubular shape, and the downflow B of the working fluid flows through the downflow channel 54. Similarly to the heat pipe 16 of the first embodiment, the upstream heat pipe section 51A is divided into an ascending flow path 16A and a descending flow path 16B by the separation plate 19, and the ascending flow path 16A is divided into the downstream heat pipe section 51B. And the descending passage 16B is continuous with the descending passage 54 of the downstream heat pipe portion 51B.

  With the configuration described above, according to the fifth embodiment, in addition to the effects (1), (2), and (5) of the first and fourth embodiments, the following effects can be obtained. (6) is performed.

  (6) In the heat pipe 51, a tubular-side downstream heat pipe portion 51 </ b> B extending outside the reactor 11 and reaching the heat radiating section 52 is provided with an ascending flow path 53 and a descending flow path 54. Therefore, the heat radiation efficiency by the heat radiation part 52 can be improved.

[F] Sixth embodiment (FIGS. 9 and 10)
FIG. 9 is a schematic vertical sectional view showing a nuclear power plant according to the sixth embodiment. In the sixth embodiment, the same parts as those in the first and fifth embodiments are denoted by the same reference numerals as those in the first and fifth embodiments, and the description is simplified or omitted.

  The difference between the nuclear power generation device 60 of the sixth embodiment and the first and fifth embodiments is that the heat pipe 61 arranged adjacent to the outside of the fuel 14 in the nuclear reactor 11 has an upward flow A of the working fluid. The flow path 61A through which the fluid flows and the descending flow path 61B through which the descending flow B of the working fluid flows is switched before reaching the heat radiating section 62.

  That is, as shown in FIG. 10, the heat pipes 16 and 51 disposed adjacent to the inside of the fuel 14 and the heat pipes 16 and 51 adjacent to the outside of the fuel 14 are provided in the reactor 11 of the first or fifth embodiment. The heat pipes 16 and 51 to be arranged are present in the structure of the nuclear reactor 11. Among these, in the heat pipes 16 and 51 arranged adjacent to the inside of the fuel 14, the working fluid flowing through the ascending flow paths 16A and 53 is condensed in the heat radiating portion 62 (radiating portions 13 and 52). The condensed working fluid M flows toward the reactor 11 through the down flow passages 16B and 54.

  However, in the heat pipes 16 and 51 disposed adjacent to the outside of the fuel 14, the working fluid flowing through the ascending flow paths 16A and 53 is condensed in the heat radiating portion 62 (the heat radiating portions 13 and 52). There is a possibility that the working fluid M that has flowed back and flows down the ascending channels 16A and 53. This is because the heat radiating portion 62 is the heat radiating portion 13 (first embodiment) or the heat radiating portion 52 (fifth embodiment) that is gradually inclined toward the outside of the reactor 11 and becomes substantially horizontal.

  Therefore, as shown in FIG. 9, in the nuclear power generator 60 of the sixth embodiment, the heat pipe 61 arranged adjacent to the outside of the fuel 14 includes the ascending flow channel 61 </ b> A and the descending flow channel 61 </ b> B. And the up flow channel 61A is positioned below the down flow channel 61B. As a result, the working fluid M ascending the ascending flow path 61A of the heat pipe 61 and reaching the heat dissipating portion 62 (the heat dissipating portions 13 and 52) is condensed with the heat pipe 16, which is disposed adjacent to the inside of the fuel 14. As in the case of 51, the gas flows through the descending flow channel 61B to the reactor 11 side, and does not flow backward through the ascending flow channel 61A.

  With the configuration described above, according to the sixth embodiment, the following effects (7) are obtained in addition to the effects similar to the effects (1) and (2) of the first embodiment.

  (7) In the heat pipe 61 disposed adjacent to the outside of the fuel 14 in the reactor 11, an ascending flow path 61A through which the ascending flow A of the working fluid flows and a descending flow path 61B through which the descending flow B of the working fluid flows. Are switched at a position in front of the heat radiating portion 62 arranged substantially horizontally. Therefore, since the working fluid M condensed in the heat radiating section 62 does not flow backward through the upflow channel 61A, a decrease in the heat transport efficiency of the heat pipe 61 can be prevented, and the power generation efficiency of the power generation section 12 can be improved. Can be secured.

  While some embodiments of the present invention have been described above, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. These embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. Is included in the scope and gist of the invention, and is also included in the invention described in the claims and its equivalents.

  DESCRIPTION OF SYMBOLS 10 ... Nuclear power generator, 11 ... Nuclear reactor, 12 ... Power generation part, 13 ... Heat radiating part, 14 ... Fuel, 15 ... Moderator, 16 ... Heat pipe, 16A ... Ascending channel, 16B ... Descending channel, 19 ... Separation Plate, 20: Nuclear power plant, 21: Reactor, 22: Split surface, 30: Nuclear power plant, 31: Heat radiating unit, 32: Split surface, 40: Nuclear power plant, 41: Heat pipe, 41B: Downstream heat Pipe part, 42: heat radiating part, 50: nuclear power generator, 51: heat pipe, 51B: downstream heat pipe part, 52: heat radiating part, 53: ascending channel, 54: descending channel, 60: nuclear power generator, 61: heat pipe, 61A: ascending channel, 61B: descending channel, 62: radiator.

Claims (8)

Fuel containing fissile material and moderator for moderating neutrons are formed in a ring and arranged alternately,
A nuclear reactor, wherein a heat pipe for transporting heat generated by the nuclear fission reaction of the fuel is formed in an annular shape and arranged between the fuel and the moderator. 2. The reactor according to claim 1, wherein a separation plate configured to separate an ascending flow and a descending flow of the working fluid is formed in an annular shape inside the heat pipe and disposed. 3. 3. The nuclear reactor according to claim 1, wherein the fuel, the heat pipe, and the moderator arranged and formed in an annular shape are divided in a circumferential direction thereof. A nuclear reactor according to any one of claims 1 to 3,
A power generation unit installed on a part of a heat pipe extending outside the reactor, and converting heat generated in the reactor into electricity;
A nuclear power plant, comprising: a heat radiating portion that radiates heat to the outside at a downstream portion of the power generating unit in the heat pipe. The nuclear power generation device according to claim 4, wherein the heat radiating portion is formed in an annular shape and is divided in a circumferential direction thereof. The nuclear power generation device according to claim 4, wherein the heat pipe is provided with a plurality of tubular portions each of which extends outside the nuclear reactor, and a heat radiating portion is provided at a tip portion thereof. 7. The heat pipe according to claim 4, wherein a portion of the heat pipe which extends outside the reactor and reaches a heat radiating portion is configured such that an ascending flow and a descending flow of the working fluid flow in different flow paths. The nuclear power plant according to claim 1. In the heat pipe arranged adjacent to the outside of the fuel in the nuclear reactor, the flow paths for flowing the upward flow and the downward flow of the working fluid are exchanged at a position near the heat radiating portion. The nuclear power plant according to claim 7, wherein

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