Manufacturing method of reactor structural material

A molding materials made of a zirconium based alloy is prepared, and annealing of the materials after applying β-quenching is controlled to set parameters of the grain size of deposited materials before annealing and the grain size of the deposited materials to not greater than 1.3 x 10-21. Corrosion resistance of zircaloy-2 is influenced by the kind, the grain size and the composition of the deposited materials present in the alloy. Then, the amount of heat to be entered is controlled by parameters which reliably represent heat treatment conditions by taking the theory of growth of different deposited materials is taken into consideration. Namely, the concentration of Fe, Cr, and Ni solid solubilized in zirconium stay as it is at an equilibrium concentration during repeating annealing and, an Ostwald aging growth model is established in which small deposition products are leached out and large deposited materials are grown. An optimum range for corrosion resistance is determined using parameters taking the growth of the deposition products into consideration since it is necessary to reduce the corrosion of structural materials at high burnup degree. (I.S.)