Composite tube for nuclear fuel element - incorporating barrier of spongy zirconium, reducing stresses and corrosion

Abstract

Abstract A nuclear fuel element has a composite outer sleeve comprising a tube made of zirconium alloy with an inner barrier made of zirconium of moderate purity, e.g. spongy zirconium. The proportion of impurities is 1000-5000 ppm. The oxygen content is 200-1200 ppm. The invention improves the fuel element described in the parent patent, in which the metallic barrier is made of pure zirconium. It ensures a longer life for the element because of the redn. in chemical attack, the redn. in localised stresses, the redn. in stress corrosion of the tube and the redn. of risk of rupture by fissuring. It a also prevents the fuel expanding so that it comes into direct contact with the zirconium alloy tube. These improvements are obtd. without increase in neutron absorption. The tube does not form eutectics if coolant is lost, heat transfer is not impaired and the tube can be inspected by standard non-destructive tests.

Inventors

• 👤 Joseph Sam Armijo
• 👤 Louis Fussel Coffin Jr

Bibliographic Details