Abstract: A fast reactor 1 includes: a reactor vessel 7 accommodating therein a core 2 and a primary coolant 21; a core support 13 supporting the core 2 from below; and a bulkhead 6 disposed on the core support 13, the bulkhead 6 extending upward and surrounding the core 2 from a lateral side. Between an inner surface of the reactor vessel 7 and the bulkhead 6, there is disposed an intermediate heat exchanger 15 configured to cool the primary coolant 21, and an electromagnetic pump 14 configured to pressurize the cooled primary coolant 21. A neutron shield 8 supported by an upper supporting plate 29 from above is disposed below the electromagnetic pump 14. The upper supporting plate 29 has an opening 29a. Between an outlet 14b of the electromagnetic pump 14 and the upper supporting plate 29, there is disposed a coolant guide mechanism 17 configured to guide the pressurized primary coolant 21 from the electromagnetic pump 14 to the neutron shield through the opening 29a of the upper supporting plate 29.

Abstract: A fast reactor performing reflector control to control reactivity of the core by moving a neutron reflector in the vertical direction, including: a core fuel assembly; a neutron absorption assembly in the middle of the core fuel assembly; a reflector assembly at the circumference of the core fuel assembly; plural inner neutron shields at the circumference of the reflector assembly; a cylindrical core barrel surrounding entirety of the plural neutron shields; and a drive mechanism controlling the reflector. The reflector assembly includes: a reflector element that reflects neutrons from the core fuel assembly towards the core; a cavity section, arranged thereabove, that permits leakage of neutrons to outside the core; a linkage mechanism that links the reflector element and the cavity section; a guide tube that defines a space for removal/insertion of these; and a connecting section that connects the drive mechanism and the cavity section.

Abstract: A neutron reactor includes a neutron shield which is disposed outside a nuclear reactor core and adapted to absorb neutrons leaking from the core. The neutron shield includes a plurality of containers each of which contains a powdered neutron absorbing material and which are stacked with one another in a vertical direction, and a cladding tube which houses the containers. The neutron absorbing material is composed of B4C powder.

Abstract: A ceramic heat exchanger includes a heat exchange section that heat-exchanges between two fluids A and B flowing opposite directions to each other. The heat exchange section includes ceramic blocks stacked one on top of another with a seal therebetween. The ceramic blocks have a plurality of parallel lines of flow channels, each line defined by the flow channels through which the same fluid flows, any two adjacent lines being defined by the flow channels through which the different fluids A and B flow respectively. Both ends in the stacking direction of the stack are bound to join and integrate the ceramic blocks with tightening means including end plates and a tie rod. A thermal expansion absorber is disposed on an external surface of the end plates for absorbing thermal expansion in the axial direction of the tie rod.

Abstract: A fast reactor having a reactivity control reflector has a reactor vessel in which a coolant is accommodated, a reactor core which is installed in the reactor vessel and dipped with the coolant, and a reflector installed outside of the reactor core so as to be movable in a vertical direction for controlling the reactivity of the reactor core. The reflector of the fast reactor has a lower neutron reflecting portion having a neutron reflection capability higher than that of the coolant and an upper cavity portion located above the neutron reflecting portion and having a neutron reflection capability lower than that of the coolant. The cavity portion is composed of a plurality of cylindrical hermetically-sealed vessels.

Abstract: A heat exchanger includes a vertical pressure vessel having a air-tight structure, one and another sets of fluid inlet/outlet ports provided to upper and lower portion of the vertical pressure vessel, respectively, and a heat exchanging module disposed in the pressure vessel to a portion between both sets of the fluid inlet/outlet ports, the heat exchanging module being formed by stacking a number of heat exchanging elements. At least one set of the fluid inlet/outlet ports are configured to provide a header composed of a pipe structural member having a bottom portion closed and a heat insulating material attached to an inner surface of the pipe structural member, and end portions of fluid flowing pipes communicating with the heat exchanging module are opened at the closed fluid inlet/outlet ports in the header.

Abstract: A fast reactor 1 includes: a reactor vessel 7 accommodating therein a core 2 and a primary coolant 21; a core support 13 supporting the core 2 from below; and a bulkhead 6 disposed on the core support 13, the bulkhead 6 extending upward and surrounding the core 2 from a lateral side. Between an inner surface of the reactor vessel 7 and the bulkhead 6, there is disposed an intermediate heat exchanger 15 configured to cool the primary coolant 21, and an electromagnetic pump 14 configured to pressurize the cooled primary coolant 21. A neutron shield 8 supported by an upper supporting plate 29 from above is disposed below the electromagnetic pump 14. The upper supporting plate 29 has an opening 29a. Between an outlet 14b of the electromagnetic pump 14 and the upper supporting plate 29, there is disposed a coolant guide mechanism 17 configured to guide the pressurized primary coolant 21 from the electromagnetic pump 14 to the neutron shield through the opening 29a of the upper supporting plate 29.

Abstract: A thermoelectric generator includes: a high temperature member which conducts thermal energy of a high temperature medium; a low temperature member which is provided on a side opposing to the high temperature medium of the high temperature member and is provided with a low temperature medium passage therein; a thermoelectric module which is sandwiched between the high temperature member and the low temperature member and carries out a thermoelectric conversion element converting a thermal energy to an electrical energy using a temperature difference between the high temperature medium and the low temperature medium supplied to the low temperature medium passage, and at least one tie rod fastening between the low temperature member and the high temperature member.

Abstract: A fast reactor has: a reactor vessel containing a coolant; a reactor core housed in the reactor vessel; a core supporting plate; a reflector; a partition arranged to surround the reflector on the side of the reactor vessel, for forming a passage of the coolant; a thermal shield arranged to cover at least one of the core side and the reactor vessel side of the partition; and a neutron shield. The thermal shield is mounted on the partition. The thermal shield includes a metallic thermal shield plate and a heat insulator mounted in the thermal shield plate, and has its inside filled with an inert gas. By the thermal shield, the thermal insulation of the partition can be improved to suppress the heat exchange between primary coolants on the core side and on the side of the reactor vessel of the partition.

Abstract: A fast reactor 1 controlled with a reflector comprises: a reactor vessel 7 accommodating therein a coolant 5; a reactor core 2 disposed in the reactor vessel 7 and immersed in the coolant 5; and a reflector 4 that vertically moves for adjusting leakage of neutrons generated from the reactor core 2 to control a reactivity of the reactor core 2, the reflector 4 including a neutron reflecting part 4a disposed on an outside of the reactor core 2 in a vertically movable manner, the neutron reflecting part 4a having a neutron reflecting ability higher than that of the coolant 5, and a cavity part 4b positioned above the neutron reflecting part 4a, the cavity part 4b having a neutron reflecting ability lower than that of the coolant 5. The neutron reflecting part 4a is formed of a plurality of metal plates 37 that are stacked on each other. Each of the metal plates 37 has a plurality of coolant channels 36 through which the coolant 5 flows.

Abstract: A reflector system of a fast reactor according to the present invention comprises a reflector having a neutron reflecting portion reflecting a neutron radiated from a reactor core, and a cavity portion provided above the neutron reflecting portion and having a lower neutron reflecting capacity than a coolant, and a reflector drive apparatus coupled to the reflector and moving the reflector in a vertical direction. The reflector drive apparatus has a driving portion which is coupled to the reflector via a drive shaft, and drives the reflector up and down, and a load sensing portion which is provided between the driving portion and the drive shaft, and senses a load of the reflector. A detecting portion receiving a load signal from the load sensing portion so as to detect a breakage of the cavity portion of the reflector is connected to the load sensing portion.

Abstract: A stacked plate type heat exchanger having compactness and providing a heat exchanging rate per unit volume of 10 MWt/m3 or more is used under conditions of high temperature and high pressure of 4 to 7 MPa of pressure difference between a primary fluid and a secondary fluid, and 500° C. to 900° C. of maximum operating temperature. A thickness of metal plate is set at 0.3 times or more of an equivalent diameter of a flow path, and a pitch between flow paths along a width direction of the metal plate is set at 0.5 times or more of the equivalent diameter of the flow path.

Abstract: A neutron reactor includes a neutron shield which is disposed outside a nuclear reactor core and adapted to absorb neutrons leaking from the core. The neutron shield includes a plurality of containers each of which contains a powdered neutron absorbing material and which are stacked with one another in a vertical direction, and a cladding tube which houses the containers. The neutron absorbing material is composed of B4C powder.

Abstract: A fast reactor having a reactivity control reflector has a reactor vessel in which a coolant is accommodated, a reactor core which is installed in the reactor vessel and dipped with the coolant, and a reflector installed outside of the reactor core so as to be movable in a vertical direction for controlling the reactivity of the reactor core. The reflector of the fast reactor has a lower neutron reflecting portion having a neutron reflection capability higher than that of the coolant and an upper cavity portion located above the neutron reflecting portion and having a neutron reflection capability lower than that of the coolant. The cavity portion is composed of a plurality of cylindrical hermetically-sealed vessels.

Abstract: A ceramic heat exchanger includes a heat exchange section that heat-exchanges between two fluids A and B flowing opposite directions to each other. The heat exchange section includes ceramic blocks stacked one on top of another with a seal therebetween. The ceramic blocks have a plurality of parallel lines of flow channels, each line defined by the flow channels through which the same fluid flows, any two adjacent lines being defined by the flow channels through which the different fluids A and B flow respectively. Both ends in the stacking direction of the stack are bound to join and integrate the ceramic blocks with tightening means including end plates and a tie rod. A thermal expansion absorber is disposed on an external surface of the end plates for absorbing thermal expansion in the axial direction of the tie rod.

Abstract: A heat exchanger includes a vertical pressure vessel having a air-tight structure, one and another sets of fluid inlet/outlet ports provided to upper and lower portion of the vertical pressure vessel, respectively, and a heat exchanging module disposed in the pressure vessel to a portion between both sets of the fluid inlet/outlet ports, the heat exchanging module being formed by stacking a number of heat exchanging elements. At least one set of the fluid inlet/outlet ports are configured to provide a header composed of a pipe structural member having a bottom portion closed and a heat insulating material attached to an inner surface of the pipe structural member, and end portions of fluid flowing pipes communicating with the heat exchanging module are opened at the closed fluid inlet/outlet ports in the header.

Abstract: A reflector control type fast reactor 1 comprises: a reactor vessel 7 accommodating therein a primary coolant 5; a reactor core 2 disposed in the reactor vessel 7 and immersed in the primary coolant 5; and a reflector 4 that vertically moves for adjusting leakage of neutrons generated from the reactor core 2 to control a reactivity of the reactor core 2, the reflector 4 including a neutron reflecting part 4a disposed on an outside of the reactor core 2 in a vertically movable manner, the neutron reflecting part 4a having a neutron reflecting ability higher than that of the primary coolant 5, and a cavity part 4b positioned above the neutron reflecting part 4a, the cavity part 4b having a neutron reflecting ability lower than that of the primary coolant 5. The neutron reflecting part 4a is formed of a plurality of metal plates 37 that are stacked on each other. Each of the metal plates 37 has a plurality of coolant channels 36 through which the primary coolant 5 flows.

Abstract: To provide a fast reactor having improved structural reliability and excellent safety. A fast reactor 1 comprises: a reactor vessel 7 accommodating therein a reactor core 2 and a primary coolant 5; an intermediate heat exchanger 15 disposed in the reactor vessel 7, for transferring a heat energy of the primary coolant 5 heated in the reactor core 2 to a secondary coolant 45; an intermediate heat exchanger upper drum 15a disposed above the intermediate heat exchanger 15. Disposed above the intermediate heat exchanger upper drum 15a is an upper plug 10 having a neutron shielding function and a heat shielding function. A thermal-expansion absorbing unit 46 is disposed between the intermediate heat exchanger upper drum and the upper plug, for absorbing a thermal expansion of the intermediate heat exchanger upper drum in an axial direction and a radial direction of the intermediate heat exchanger upper drum, and defining a reactor cover gas boundary.