Patent Number: 050341855
Section: abstract

A control blade for a nuclear reactor having inserted upper end structural members and inserted lower end structural members connected to a plurality of wings each in the form of a generally rectangular plate having an longitudinal axis extending in the longitudinal direction of the control blade, the wing being disposed to form a cross-shaped section of the control blade. The wings and the structural members are connected to and supported on a central connection member. Each wing or a sheath member formed within each wing is formed from a diluted alloy obtained by diluting a long-lived neutron absorber such as hafnium with a diluent such as zirconium or titanium. A plurality of neutron absorber housing holes are formed in the diluted alloy section. Specifically, if the housing holes are formed to extend in the widthwise direction of the wing, the sectional area of each housing hole formed in a portion of the control blade corresponding to the region where the subcriticality in the reactor core becomes smaller after the reactor has been shut down by fully inserting the control blade into the core is larger than that of housing holes formed in the other regions. A structure having a means to cope with swelling of the neutron absorber can be applied to the former region.