noun
fissionable material
Technical term used in nuclear physics and engineering; refers to substances capable of sustaining a nuclear fission chain reaction.
ウラン235は代表的な分裂物質です。
Uranium-235 is a typical fissionable material.
核分裂 is the process of nuclear fission, while 分裂物質 refers to the material that undergoes fission.
Compound of 分裂 (fission, splitting) and 物質 (material, substance).