小型原子炉による熱中性子ラジオグラフィ

抄録

Thermal neutron radiography by the use of Toshiba Training Reactor (max. output 100 kW) has been studied concerning its possibility of being used as an industrial testing device of low cost. A neutron beam of Cd-ratio 3.5 (In) from the reactor core is satisfactorily collimated with a col-limator of simple design, which gives fairly good pictures by the image transfer method with In screen. The effectiveness of the collimator for imaging is discussed with relation to energy spec-trum of neutron in the reactor. Several neutron radiographs and ordinary X-ray radiographs are shown for comparison. Cadmium shadowing method is newly introduced for sensitive detection of hair cracks and porous portions in the sample. Heavily irradiated radioactive nuclear fuel in the form of UO₂ pellet is radiographed to prove that the thermal neutron radiography is free from γ-ray fogging. The effects of scattering of neutrons in sample materials on the resolving power are briefly discussed.