Vib-Swaging Process for Fuel Rod

Abstract

A series of experiments has been conducted for gaining information to contribute to the vib-swaging process as a practical method for fabricating fuel rods. The present report covers, in particular, observations made on the relationship between the properties of the intermediate compact before swaging and the final swaged product, in respect of bulk density and dimensions. Selection of a suitable pre-swage density and initial cladding tube dimensions is very important for consistently obtaining products of acceptable properties. Equations have been derived to relate quantities representing the dimensions and properties of the compact and cladding tube before and after swaging. These equations should prove useful for estimating the bulk density and wall-thickness of the swaged rod. The reduction ratio per step of swaging should be kept to a level below about 10%. Largor particles in the compact tend to indent the inner surface of the cladding tube during swaging process, and from this standpoint very coarse particles are not desirable. The following conditions for vib-swagiug are proposed as suitable for preparing fuel rods ol 92%T.D. from fused U02 powder (about 99%T.D. partido density). UO2 powder: less than 14 mesh Reduction ratio: less than 10% per one step 22 to 14% for total Pre-swage density: 81 to 85%T.D. These conditions are also valid for fabricating to JPDR-1 fuel rod specifications.