CONTROLLER FOR LONG-LIFE NUCLEAR REACTOR

PURPOSE: To prolong the service life of a controller for nuclear reactor by installing a strip shaped unit including of metallic hafnium units and boron carbide units alternately between an upper supporting member and a lower supporting member. CONSTITUTION: Two metallic hafnium units 28 are set adjacent to each other at the outer most section of a sheath type covering body 22, and at all the sections except the outmost section, boron carbide units 24 and the metallic hafnium units 28 are arranged alternately one by one. They are stored in the sheath type covering body 22 and disposed the upper supporting member 16 and the lower supporting member 18. As a result, the metallic hafnium section is capable of maintaining effective neutron absorbing performance even if it is exposed to high neutron density, providing longer service life.