RECONSTITUTING METHOD OF PARTIALLY USED NUCLEAR FUEL ASSEMBLY

摘要

PROBLEM TO BE SOLVED: To sustain the characteristics of reactor by employing a new fuel rod containing no flammable material and setting the mixing ratio between a neutron transmissive material and a neutron absorbing material such that the average output and radial power factor of assembly do not vary more than specified % at any position of an alternative fuel rod when it is loaded into the reactor. SOLUTION: A new fuel rod containing no flammable material is substituted for an old fuel rod thus employing a mixture of a neutron transmissive material and a neutron absorbing material. The mixing ratio is set such that the average output and radial power factor of assembly do not vary more than 8% and 1%, respectively, at any position of an alternative fuel rod when it is loaded later into a reactor. Consequently, variation in the output and power factor of assembly are confined within allowable ranges without using plutonium or other fissionable material.