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 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: 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.

Abstract: A fuel inlet mechanism to introduce a coolant into a fuel assembly configured to be charged in a light water nuclear reactor, includes, a filter catching a foreign substance included in the coolant on an upstream side of the fuel assembly, the filter having a plurality of through holes to pass the coolant, and the through holes having an inlet portion, an outlet portion and at least one bent portion to a degree by which the outlet portion cannot be seen through from the inlet portion by a straight line.

Abstract: A fuel inlet mechanism to introduce a coolant into a fuel assembly configured to be charged in a light water nuclear reactor, includes, a filter catching a foreign substance included in the coolant on an upstream side of the fuel assembly, the filter having a plurality of through holes to pass the coolant, and the through holes having an inlet portion, an outlet portion and at least one bent portion to a degree by which the outlet portion cannot be seen through from the inlet portion by a straight line.

Abstract: A fuel inlet mechanism to introduce a coolant into a fuel assembly configured to be charged in a light water nuclear reactor, includes, a filter catching a foreign substance included in the coolant on an upstream side of the fuel assembly, the filter having a plurality of through holes to pass the coolant, and the through holes having an inlet portion, an outlet portion and at least one bent portion to a degree by which the outlet portion cannot be seen through from the inlet portion by a straight line.

Abstract: There is provided a reactor internal equipment hoisting apparatus which is hung down from an upper side of a reactor pressure vessel to hoist reactor internal equipment installed inside the reactor pressure vessel. The hoisting apparatus includes a supporting unit which is hung down from the upper side of the reactor pressure vessel with an overhead travailing crane installed on the ceiling of the reactor building, and an elevating unit which is arranged below the supporting unit. A coupling/fixing unit is provided to the elevating unit to be releasably coupled with a hoisting lug. Power hoist using a wire rope or a chain is provided to the supporting unit. The elevating unit is hung down from the supporting unit via the rope or the chain to be moved vertically. This reactor internal equipment hoisting apparatus is easy in maintenance and storage.