Pellet take-out device

An annular radio frequency heater for heating a spent nuclear fuel can and an annular coolant spray pipe for cooling the spent nuclear fuel can are disposed in parallel along the axis of the pipes so as to surround the spent nuclear fuel can. This causes a great temperature slope along the axis of the pipe of the spent nuclear fuel can and causes plastic deformation expansion due to thermal ratchet strain to expand the diameter of the fuel can. In this case, since the sintered pellets of uranium dioxide are not expanded but can be taken out from the spent nuclear fuel can, use of a shearing device may be saved. Accordingly, the installation and the running costs of a reprocessing plant can be reduced and the operation efficiency and the dissolving rate can be improved. (T.M.)