Neutron absorbing member, critical state generation prevention method and fissile material recovery method

摘要

PROBLEM TO BE SOLVED: To provide a neutron absorption member capable of recovering, without causing recriticality, debris that contains a fissile material and exists in a pressure vessel or containment vessel in a nuclear reactor, and to provide a method of recovering the debris from a reactor pressure vessel or containment vessel using the neutron absorption member.SOLUTION: The present invention provides a neutron absorption member including a heat-resistant and radiation-resistant sheet-like material and a neutron absorber fixed on the sheet-like material, a fissile material recovery method of making the neutron absorption member absorb a fissile material inclusion and recovering the fissile material inclusion, and a critical state occurrence preventing method of preventing occurrence of a critical state with the neutron absorption member.