Abstract: An input apparatus includes a casing including an opening, a knob exposed to outside along a virtual central axis, a first support member that supports the knob so as to be capable of a first operation, a second support member that supports the first support member so as to be capable of a second operation of the knob, a first detection member that detects the first operation, a second detection member that detects the second operation, and a detachable regulating member that regulates movement of the second detection member. The second support member includes a groove extending parallel to the virtual central axis. When the second operation is to be disabled, the regulating member including a rib to be fitted in the groove is attached. When the second operation is to be enabled, the regulating member not including a rib to be fitted in the groove is attached.

Abstract: An input apparatus includes a casing including an opening, a knob exposed to outside along a virtual central axis, a first support member that supports the knob so as to be capable of a first operation, a second support member that supports the first support member so as to be capable of a second operation of the knob, a first detection member that detects the first operation, a second detection member that detects the second operation, and a detachable regulating member that regulates movement of the second detection member. The second support member includes a groove extending parallel to the virtual central axis. When the second operation is to be disabled, the regulating member including a rib to be fitted in the groove is attached. When the second operation is to be enabled, the regulating member not including a rib to be fitted in the groove is attached.

Abstract: A pressing operation device is configured such that a base and an operating body are linked to each other by a link member. A support-side shaft of the link member is rotatably supported by a bearing of the base. The bearing of the base includes a first regulation portion that regulates movement of the support-side shaft of the link member in an ascending direction of the operating body and a second regulation portion that regulates movement of the support-side shaft in a direction intersecting the ascending direction, and is provided with a flat spring portion that presses the support-side shaft against the second regulation portion and the first regulation portion.

Abstract: A pressing operation device is configured such that a base and an operating body are linked to each other by a link member. A support-side shaft of the link member is rotatably supported by a bearing of the base. The bearing of the base includes a first regulation portion that regulates movement of the support-side shaft of the link member in an ascending direction of the operating body and a second regulation portion that regulates movement of the support-side shaft in a direction intersecting the ascending direction, and is provided with a flat spring portion that presses the support-side shaft against the second regulation portion and the first regulation portion.

Abstract: A control rod has blades each of which includes a neutron absorption region in which neutron absorbers each loaded to the core of a reactor from below and made of absorption nuclear chain type neutron absorber are disposed. The neutron absorption region is divided into two, upper and lower, regions in an axial direction; the boundary between the upper and lower regions is positioned within the range of from 3/8 to 5/8 of the full length of the neutron absorption region in the axial direction from the lower end of the neutron absorption region; and the quantity of the absorption nuclear chain type neutron absorber contained in the lower region in the section perpendicular to the axial direction is smaller than the quantity of the absorption nuclear chain type neutron absorber contained in the upper region in the section perpendicular to the axial direction.

Abstract: A fuel assembly including a channel box, upper and lower tie plates, fuel rods inserted in the channel box and held at upper and lower end portions by the upper and lower tie plates, a water rod disposed among the fuel rods and spacers for keeping the fuel rods and the water rod spaced from one another. The water rod has a diameter larger than that of each of the fuel rods and the upper end of the water rod has a height substantially as high as an upper end of an effective enriched fuel section of each fuel rod.

Abstract: A fuel assembly has a fuel spacer consisting of a water rod having an outer diameter greater than that of fuel rods and a large number of circular sleeves into which the fuel rods are inserted. The fuel spacer has four bridge members. Both ends of these bridge members are fitted to two of eight circular sleeves which are adjacent one another in the diagonal direction of the fuel spacer. Both ends of each bridge member are bent so that its center projects outwardly away from the water rod.

Abstract: A nuclear reactor having a reactor vessel adapted to be supplied with a coolant, a reactor core disposed in the reactor vessel and including a plurality of fuel assemblies, a plurality of control rods adapted to be inserted into the reactor core and a plurality of control rod driving devices for driving the control rods into and out of the reactor core. A plurality of tubular coolant passage members are disposed above the fuel assemblies so as to receive the heated coolant discharged from the fuel assemblies, so that the heated coolant flows upwardly through the tubular coolant passage members. The tubular coolant passage members provide a chimney effect which enhances the upward flow of the coolant and, hence, increases the flow rate of coolant flowing through the reactor core. In consequence, a greater cooling effect is obtained and the range of power controllable by the control rods is widened.