高こう速そく中ちゅう性せい子しこうそくちゅうせいしMeanings1nounfast neutronTechnical term in nuclear physics for a neutron with kinetic energy above a certain threshold, typically around 1 MeV.高こう速そく中ちゅう性せい子しは原げん子し炉ろの設せっ計けいで重じゅう要ような役