FISSION PRODUCT ANNIHILATING ASSEMBLY AND FAST REACTOR CONTAINING IT

摘要

PURPOSE: To suppress increase of the internal pressure of cover tubes by loading the cover tubes storing a compound containing129 I in a part of a fission product annihilating assembly, and loading the cover tubes containing the fission products other than129 I in the other region. CONSTITUTION: Cover tubes 2 storing a material 3 mixed with CeI3 and ZrH1.6 are loaded in a part of the fission product annihilating assembly, and the cover tubes 2 storing a material 4 mixed with99 Tc and ZrH1.6 are loaded in the other region. 25 % of I in CeI3 is127 I, and 75% of I is129 I. The neutron capture cross section of129 I is small in the high-energy region, high-speed neutrons cannot efficiently annihilalte129 I, and neutrons are decelerated by ZrH1.6 to the low-energy region to efficiently annihilate129 I.99 Tc is loaded in the high- thermal neutron flux region, CeI3 is loaded in the low-thermal neutron flux region, thus the annihilation quantity of129 I is smaller than that of99 Tc, however the internal pressure increase of the cover tubes 2 due to130 Xe converted from129 I can be suppressed.