Zirconium alloy for nuclear reactor

In a Zr alloy for a nuclear reactor comprising Sn, Fe, Cr, Ni, Zr and inevitable impurities containing, based on the entire amount, from 1.20 to 1.70% by weight of Sn, from 0.07 to 0.20% by weight of Fe, from 0.05 to 0.15% by weight or Cr, from 0.03 to 0.08% by weight of Ni and from 0.18 to 0.38 by weight of Fe, Cr and Ni in total, a rare earth element having an atomic number of smaller than 60 and oxides of which have a CaF2 type crystal structure, namely, either of Ce and Pr is added to the zircaloy-2 alloy so that the content thereof based on the entire amount is up to 0.3% by weight. With such a constitution, occurrence of break away phenomenon can be suppressed while reducing nodular corrosion. (T.M.)