Guide roller for control rod drive of nuclear power plant

摘要

PROBLEM TO BE SOLVED: To improve wear resistance as well as corrosion resistance and impact resistance by specifying respective quantities of C and Cr in an Fe-base or Ni-base alloy for control rod drive device and controlling the amount of chromium carbide precipitated and the amount of Cr in a matrix, respectively. SOLUTION: C and Cr are incorporated by 1.0-3.0% and 12-50% by weight ratio, respectively, into the composition of a wear resistant alloy composed of Fe- or Ni-base alloy. Moreover, rod-like chromium carbide is incorporated, and the amount of chromium carbide is regulated to 10-28.5% by area ratio and in amount of chromium carbide, remaining in matrix, of =10% is secured. Further, the Vickers hardness of this matrix at room temp. is regulated to 230-260. If necessary, 0.1-1.5%, in total, of either or both of Ti and Nb are incorporated into the alloy composition. By using this wear resistant alloy, the smooth drive of a nuclear reactor control rod can be ensured over a long period in high temp. water under high load. Moreover, because this alloy is free from cobalt, exposure dose can be reduced and the safety of a nuclear power plant can be increased.