インバース・ポール・フィギュアーによる燃料ウランロッドの解析, (I)

Abstract

To develop the fuel element for Japan Research Reactor-3, the properties of uranium fuel rod fabricated into 10m/m in diameter, are studied, and a part of the results has. already been reported in this journal. The effect of β-treatment on uranium fuel rod were studied from the points of thermal cycling growth coefficient, thermal expansion coefficient, hardness and microstructure, which has been reported in the reference. The effect of β-treatment on the texture of the same uranium fuel rod, as was used in the previous study is reported this time. As the preparation of the pole figure of a uranium fuel rod is very troublesome, inverse pole figure method has been prefered, to describe the texture of the specimen. (001) projection of α uranium is used in this inverse pole figure. Intensities of the diffractions from 22 planes of a specimen have been measured by G.E. diffractometer and they are used for calculation. Inverse pole figures of β-treated uranium rods rolled at 300° and 600°C respectively have also been made. From the results, β-treatment at 720°C has been found to have better effect on the texture of uranium rod than that at 680°C; more homogenous distribution of crystallographic planes could be obtained, which is, therefore, the reason why β-treatment at 720°C will give smaller thermal cycling coefficient. The more homogenous is the distribution of the planes in the β-treated specimen, the smaller thermal cycling coefficient can be obtained.