Neutronic study on a magnetic fusion reactor using protective liquid wall of thorium molten salts

APEX is a new fusion reactor design that uses a liquid wall between the fusion plasma and the solid first wall for either tritium breeding or energy transfer. This liquid wall also allows using high neutron wall loads and reduces the radiation damage at the first wall to get high performance for the reactor. Additional improvement can be obtained by using salts containing fissionable isotopes as a liquid wall in fusion blankets with respect to energy multiplication and fissile fuel breeding. In this study, the neutronic performance of the APEX fusion reactor using various molten salts was investigated. Neutron transport calculations were performed with the code, Scale 4.3. The results showed that the salt, 75% LiF–23% ThF4–2% 233UF4 exhibited the best neutronic performance among the investigated salts. It increased the energy multiplication factor (M) to 14 and produced high quality fissile fuel, ∼26.800 kg 233U/year for a liquid wall thickness of 40 cm.