Texture and irradiation growth in EBR-II driver fuel

Abstract

Preferred-orientation studies of centrifugally bonded EBR-II fuel pins showed that the pins have an axial texture characterized by a preponderance of [001] and [110] poles and a deficiency of [021] poles. This texture is responsible for their diametrical growth and shortening in length during irradiation. The growth indices calculated from the texture data correlate well with the observed diametrical irradiation growth rate of the pins and give a single crystal growth rate, g, of 430% per percent burnup, which is in the range measured for uranium and uranium alloys. The texture is shown to be caused by compressive stresses from centrifuging during the γ → α transformation of the fuel pin at 500°C. Atomistic mechanisms for the texture formation produced by the compressive stress are discussed.