Anisotropic irradiation growth of EBR-II driver fuel pins

A US perspective on fast reactor fuel fabrication technology and experience part I: metal fuels and assembly design

“…Centrifugal bonding takes advantage of a consistent, continuous centrifugal force to accomplish bonding of the sodium to the fuel slug, rather than utilizing sharp impacts generated by repeated contacts between the cladding tube and an anvil, such as that used for impact bonding that is described later. However, a deleterious texturing effect was found to occur upon irradiation of the centrifugally bonded U-5Fs fuel elements as a result of increased axial compressive stress typically not observed with impact bonding [30]. The fuel slugs were observed to shorten axially and expand radially, leading to an undesired loss in fuel reactivity in the reactor core and requiring compensation through control rod motion [33].…”

“…Texture of the U-5Fs slugs was determined by X-ray diffraction at six locations in the sample fuel slug for the purpose of detecting the quenched-in gamma phase and by measuring and normalizing the reflected intensities from the (1 1 0) to the (0 2 1) [29]. A 1 h heat treatment was employed to convert gamma phase U to alpha phase, thereby minimizing any preferred crystallographic orientation that occurred in the U-5Fs metal alloy elements [30,31].…”