Qeybta hoose ka dibna ka jawaab su'aasha afka isku midka ah ee marinka: Marinka: Inta badan fal-celinta fission waa fal-celinta neutron-ka kuleylka ah ee isticmaala moderator neutron si loo yareeyo ("kuleyliyaha") neutrons ee ay soo saarto fission nuclear. Xakamaynta waxay si weyn u kordhisaa qaybta qaybta kuleylka ee nuucyada fissile sida uranium-235 ama plutonium-239. Intaa waxaa dheer, uranium-238 waxay leedahay qaybta qaybta kuleylka ee aadka u hooseysa ee nuucyada kuleylka, taasoo u oggolaanaysa in neutrons badan ay sababaan fission ee nuucyada fissile iyo faafinta fal-celinta silsiladda, halkii ay ku qabsan lahaayeen 238U. Isku-darka saameyntan ayaa u oggolaanaya in fal-celinta biyaha fudud ay isticmaalaan uranium-ka yar ee la xoojiyay. Reactors-ka biyaha culus iyo graphite-moderated reactors waxay isticmaali karaan uranium dabiici ah xitaa maada
qalabka tamarta ku shaqeeya ee loo yaqaano thermal-neutron reactors oo isticmaala moderator neutron si uu u yareeyo