Hitachi, Ltd.

Shozo Saito

Takashi Saito

Yuichiro Yoshimoto

Hiromasa Hirakawa

Takashi Fukumoto

Katsutoshi Shinbo

Takeshi Suzumura

Takao Igarashi

Satoshi Sugawara

Masataka Ohwada

Takeshi Sujumura

Zenichiro Endo

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.

Control rod

A method and an apparatus for detecting failure of nuclear fuel by means of a multi-handle automatic sipper, which comprises a shipper capping operation of mounting a sipper cap of the apparatus for detecting failure of nuclear fuel on the top part of fuel assemblies, an isolation operation of supplying air into the cap after completion of sipper capping operation, thereby forming an air layer, and isolating the fuel assemblies to be detected from other fuel assemblies, a soaking operation of keeping the fuel assemblies in the isolated state for a predetermined period of time, a cell water removal operation of discharging water from system, and a sampling operation of introducing a predetermined amount of cooling water in the fuel assemblies to a sample water receptacle, the operations being provided in sequence, and other operations being carried out in parallel with the aforementioned operations.

Method and apparatus for detecting failure of nuclear fuel

An apparatus for detecting failure of the nuclear fuel rod has an outer cap and 16 (sixteen) inner caps. In checking for any faulty fuel rods, the outer cap is placed to cover the upper ends of 16 (sixteen) fuel assemblies mounted in the reactor core, while the inner caps in the outer cap are disposed on corresponding one of the fuel assemblies. To the outer cap are attached 4 (four) air supplying hoses. The inner caps receive corresponding one of 16 sampling tubes attached to the outer cap, and coolant sampling hoses are connected to the sampling tubes. A bundle member is fixed to the center of the upper surface of the outer cap. The four air supplying hoses and 16 coolant sampling hoses are fixed to the bundle member. The bundle member has a handle attached thereto.

Apparatus for detecting failure of the nuclear fuel rod

Apparatus including two types of cutting means or roller cutters and shears for cutting a channel box for a fuel assembly for a nuclear reactor and method therefor. The roller cutters and shears are located in the lower portion of a casing having inserted thereinto the channel box from which the fuel assembly has been removed, with the shears being located beneath the roller cutters. The roller cutters continuously cut the channel box axially thereof, while the shears shear the axially-split portions of the channel box in a direction intersecting the center axis of the channel box. Means for outwardly expanding the axially-split portions of the channel box is provided between the roller cutters and the shears. Means for downwardly moving the channel box in the casing is inserted in the casing. Means for drawing off coolant from the casing to clean the latter is connected to the upper portion of the casing.

Apparatus for cutting channel box for fuel assembly and method therefor

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Hitachi, Japan

Shozo Saito