Concrete cylinder-like vessel and its mfg. method

Abstract

Provided is a sealed type concrete cask keeping a conventional heat removal performance or having a higher heat removal performance than hitherto, and preventing leak of radioactivity to the outside. This concrete cask A has a formation wherein a shielding body 3 made of concrete and a metal heat-transfer fin 11 are provided between a metal inner cylinder 7 and an outer cylinder 4, and a storage part for storing a radioactive material x is provided inside the inner cylinder 7. The storage part has a sealed structure so as to be blocked from the cask A outside. The heat-transfer fin 11 is provided so that its outer cylinder 4 side part is in contact with the outer cylinder 4, and is notched so that its inner cylinder 7 side part forms a separate part relative to the inner cylinder 7.

Description

technical field [0001] The invention relates to a concrete cylindrical container suitable for transporting or storing radioactive materials such as used nuclear fuel for a long time. Background technique [0002] As conventional concrete cylindrical containers, those described in Patent Document 1 and Patent Document 2 below are known. Patent Document 1 is a typical conventional concrete cylindrical container, and an exhaust port is provided in the upper part of the concrete cylindrical container, and an air supply port is provided in the lower part. This structure is for the external air to enter from the air supply port and discharge from the exhaust port, and to form convection in the gap between the concrete cylindrical container and the sealed cylinder, thus to the sealed cylinder stored inside the concrete cylindrical container ( A structure that removes heat from a sealed container that contains used fuel. [0003] Patent Document 2 has a structure of a metal cylind...

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Problems solved by technology

Furthermore, since there is a part (shield missing part) that cannot be covered by the shield as the opening of the above-mentioned air supply and exhaust port, the outflow of radiation from the opening is unavoidable, which is not desirable.

[0007] In the structure of the above-mentioned patent document 2, since the inner cylinder and the outer cylinder are connected to the whole of both ends of the heat conduction sheet, there is no shielding body on the heat conduction sheet, and there is a problem that radiation passes through the heat conduction sheet and flows out in the radial direction.

Moreover, due to the structure in which the heat conduction sheet is in contact with the inner and outer cylinders, neutron shielding materials such as concrete must be poured in the spaces enclosed by the inner and outer cylinders and the heat conduction sheet, or assembled with block materials, increasing made trouble

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