Patent ID: 8121243

Claim:
An in-core-monitor-guide-tube supporting apparatus configured to be disposed in a reactor vessel, the apparatus comprising: a plurality of in-core monitor guide tubes configured to guide a plurality of in-core neutron monitors that measure neutrons in the reactor vessel, and comprising upper tie-plate fixing sections and lower tie-plate fixing sections projecting in a radial direction of the in-core monitor guide tubes; a plurality of control-rod guide tubes being cylindrical in shape, and configured to function as guide tubes in each of which a control rod is driven; a core support plate, wherein each of the plurality of control-rod guide tubes has first and second ends opposite to each other, and the second end is located closer to the core support plate than the first end; a plurality of control-rod-guide-tube fixing sections formed by flanges being substantially rectangular in shape when viewed in an axial direction of the control-rod guide tube, wherein the plurality of control-rod-guide-tube fixing sections are fixed to the second ends of the control-rod guide tubes, and are detachably fixed to an upper surface of the core support plate with bolts without being in direct contact with a lower surface of the core support plate such that each of the control-rod guide tubes is removable in the axial direction of the control-rod guide tube together with the corresponding control-rod-guide-tube fixing section; a plurality of tie plates including an upper tie plate fixed to the upper tie-plate fixing sections of the in-core monitor guide tubes and a lower tie plate fixed to the lower tie-plate fixing sections of the in-core monitor guide tubes, wherein a thickness direction of the tie plates is an axial direction of the in-core monitor guide tubes, wherein a plurality of monitor-guide-tube through-holes and control-rod-guide-tube through-holes are formed in the tie plates in positions corresponding to the in-core monitor guide tubes and the control-rod guide tubes, wherein the control-rod-guide-tube through-holes are formed such that not only the control-rod guide tubes but also the control-rod-guide-tube fixing sections can pass through the control-rod-guide-tube through-holes; an upper-tie-plate rib formed from the upper tie plate towards the core support plate; an upper-tie-plate flange connected to an end in a direction of the core support plate of the upper-tie-plate rib; a lower-tie-plate rib formed from the lower tie plate towards the upper-tie-plate; and a lower-tie-plate flange connected to an end in the top cover direction of the lower-tie-plate rib, connected to the upper-tie-plate flange and fixed to the core support plate.