EVALUATION OF CORROSION BEHAVIOR OF ZIRCONIUM ALLOY

摘要

PROBLEM TO BE SOLVED: To estimate the corrosion in a nuclear reactor by evaluating the corrosion behavior on the basis of the concn. change of constituent elements of a precipitate in a zirconium alloy eluted into a matrix by the collisions of neutrons or the like. SOLUTION: An intermetallic compd. consisting of Zr, Fe and Ni is precipitated in zircalloy-2 being a zirconium alloy used in fuel of a boiling water light- water reactor or the like. Fe and Ni are eluted from this precipitate by the expelling due to fast neutrons and the solid soln. concn. of them in an alloy matrix increases but, by calculating the Fe+Ni solid soln. concn. change rate immediately after the start of steady operation by predetermined operation using, for example, the chemical compsn. of zircalloy-2, the particle size or compsn. of the precipitate or fast neutron irradiation quantity, the corrosion behavior in a nuclear reactor can be evaluated. If the solid soln. concn. change rate is large, dense and uniform corrosion is formed but, if it is small, nodular corrosion wherein corrosiveness is easy to deteriorate is generated.