Nuclear fuel elements

Purpose: To reduce the amount of impurities equal to or less than that of crystal bar zirconium, thereby prevent stress corrosion cracks in a fuel can. Constitution: By applying electron beam welding to pure zirconium (sponge zirconium or forged pure zirconium), the total amount of impurities contained in zirconium such as Cu, Ca, Na, Mg, Ni, O and Fe is reduced to less than 0 - 1000 ppm, while the oxygen concentration is reduced to less than 200 - 400 ppm. The stress corrosion crack in the fuel can be prevented by using such zirconium to a zirconium liner layer in a composite type fuel can. (Takahashi, M.)