Fuel cladding tube

A mother material of a fuel cladding tube includes a Zr alloy containing alloy elements selected from Sn, Fe, Cr, Ni and Nb, and a zircaloy 2 and a zircaloy 4 are mentioned as typical examples. As an inner layer tube, a Zr alloy containing Nb or Nb and Si in Zr is used as a liner material which is softer than the Zr alloy of the mother material and has a function of existent pure Zr liner materials of moderating stresses upon occurrence of SCC, as well as has steam corrosion resistance and hydrogen absorption resistance. Nb has corrosion resistance in steams at high temperature, and improves resistance against hydrogen absorption. The content of Nb is from 0.05 to 0.75wt%, preferably from 0.15 to 0.60%. Si further improves corrosion resistance in steams at high temperature. The content of Si is from 0 to 0.020wt%. This can provide SCC resistance, as well as prevent secondary rupture due to corrosion in steams at high temperature and hydrogen absorption of the Zr alloy tube. (T.M.)