Nuclear-reactor fuel rod with double-layer cladding tube and fuel assembly containing such a fuel rod

摘要

A fuel rod has a cladding including a thicker inner layer and a thin outer layer being metallurgically bound thereto. In view of the conditions prevailing on the inside of the cladding tube and the mechanical properties of the entire cladding tube, the inner layer is formed of zircaloy having a comparatively high Sn content and a low Fe and Fe+Cr content. The outer layer also contains virtually only zircaloy constituents, but in view of corrosion, H2 take-up and sensitivity to Li dissolved in the cooling water, the Fe and Fe+Cr content is greater than or at most equal to that of the inner layer, the chosen Sn content is less than 1.3% and the chosen Sn+Fe+Cr content is more than 1.0%. Low failure rates of the cladding tube are thereby achieved even for long service lives.