FISSION PRODUCT AGGREGATE AND REACTOR CORE LOADED WITH THE SAME

PROBLEM TO BE SOLVED: To effectively extinguish radioactive fission products by irradiation of a high thermal neutron flux rate.SOLUTION: A fission product aggregate 10 includes: a plurality of fission product rods 20 allowed to be stored in a reactor, arrayed like a grid and vertically extending in parallel with each other; a deceleration member arranged so as to surround an outer periphery of the fission product rods 20 in a diameter direction; a lower tie plate 12 for mutually tying the fission product rods 20 and a lower part of the deceleration member; and an upper tie plate 13 for mutually tying the fission product bars 20 and an upper part of the deceleration part. Each of the fission product rods 20 includes a cylindrical cladding tube 22, a fission product material including fission products and filled in the cladding tube 22, a lower end plug 23 for sealing a lower part of the cladding tube 22, and an upper end plug 24 for sealing an upper part of the cladding tube 22.