STUDY OF A CON CEP TUAL AC CEL ER A TOR DRIVEN SYS TEM LOADED WITH THO RIUM DI OX IDE MIXED WITH TRANS URANIC DI OX IDES IN TRISO PAR TI CLES

Nu clear spent fuel man age ment is one of the top ma jor sub jects in the uti li za tion of nu clear en ergy. Hence, so lu tions to this prob lem have been in creas ingly re searched in re cent years. The ba sic aim of this work is to ex am ine the fis sile breed ing and trans uranic fuel trans mu ta tion po ten tials of a gas cooled ac cel er a tor-driven sys tem. In line with this pur pose, firstly, the con cep tu ally de signed sys tem is op ti mized by us ing sev eral tar get ma te ri als and fuel mix tures, from the point of neutronic. Sec ondly, three dif fer ent ma te rial com po si tions, namely, pure lead bis muth eutectic (LBE), LBE+nat u ral UO2, and LBE+15 % en rich ment UO2, are con sid ered as tar get ma te rial. The tar get zone is sep a rated to two sub-zones but as one within the other. The outer sub-zone is pure LBE tar get, and the in ner sub-zone is ei ther UO2 or pure LBE tar get.The UO2 tar get sub-zone is cooled with he lium gas. Fi nally, the tho rium di ox ide mixed with trans uranic di ox ides, dis charged from PWR-MOX spent fuel, in peb bles com posed of graph ite and TRISO-coated spher i cal fuel par ti cles, is used for breed ing fis sile fuel and trans mut ing trans uranic fu els. Three dif fer ent tho rium-trans uranic mix tures, (Th, Pu)O2, (Th, Cm)O2, (Th, Pu, MA)O2, are ex am ined with var i ous mix ture frac tions. The pack ing frac tions of the fuel peb bles in the trans mu ta tion core and the tristructural-iso tro pic coated fuel par ti cles in a peb ble are as sumed as 60 % and 29 %, re spec tively. The trans mu ta tion core is also cooled with a high-tem per a ture he lium cool ant. In or der to pro duce high-flux neu trons that pen e trate through the trans mu ta tion core, the tar get is ex posed to the con tin u ous beams of 1 GeV pro tons. The com pu ta tions have been car ried out with the high-en ergy Monte Carlo code MCNPX us ing the LA150 li brary. The nu mer i cal out comes show that the ex am ined ac cel er a tor-driven sys tem has rather high neutronic data in terms of the en ergy pro duc tion and fis sile fuel breed ing.