Composite fuel cladding tubes and its fabrication

Purpose: To decrease the mechanical interactions between fuel pellets and a cladding tube. Constitution: A composite fuel-cladding tube comprises a zirconium alloy cladding-tube and a titanium metal layer formed and integrally joined metallurigically to the inside thereof. A plurality of fuel pellets are charged in layers to the inside of the cladding tube and settled by a spring abutted against the upper-end plug. Thus, mechanical interactions between the pellets and the cladding tube can be decreased so as to reduce the stress-corrosion crackings in the cladding tube due to fission products such as gaseous iodine, as well as the manufacturing cost of the composite cladding tube can be reduced since titanium is available at a reduced cost. (Seki, T.)