The signification of fast breeder reactors as an inexhaustible source of energy has been elucidated by many researchers. Molten Salt Reactors (MSRs) show great promise in fuel cycle performance. Fuel selection for MSRs is a key parameter due to its effect on many fundamental parameters of neutronic, safety, and fuel cycle through the neutron spectrum changes. choosing the fuel for MSRs has many degrees of freedom due to the variety of salts, carrier salts, and fissile and fertile isotope types. The foremost objective of this paper is a comparison of performance of fluoride and chloride fuels with the Th-U cycle for Molten Salt Fast Reactor (MSFR) concept. For this purpose, six fuels with start-up fissile isotopes of 233U, TRansUranium (TRU), and TRU/enrU are modeled by Monte Carlo Serpent 2 code. According to the MSFR design, the fuel compositions of three fluoride fuels are chosen from different conceptual designs. Chloride fuels, however, are selected based on the limit of the maximum melting point of salts (565 degrees C), criticality at the beginning of the cycle (BOC), and inherent safety criteria (temperature reactivity coefficients). The most important evaluated parameters include the energy spectrum, absorption and fission reaction rate, kinetic parameters, temperature reactivity coefficients, power density distribution, breeding ratio, and inventory changes of important isotopes during the burnup cycle. The results reveal neutron spectrum is less fast with fluoride salt; in contrast neutron leakage of chloride fuels are more than fluoride fuels due to their harder spectrum and transparency. Furthermore, the high leakage reduces the neutron budget required for breeding 232Th to 233U and the low density of chloride fuels causes a lower loading of fissile and fertile isotopes in the reactor. Therefore, using chloride fuels leads to larger core volume and need a proper reflector to reduce neutron leakage; Anyway, the U-Pu cycle shows better indications of the breeding for chloride fuels than the Th-U cycle. By the way corrosion and radioactivity of generated elements in chloride fuel circuit are serious problems.
Neutronic and fuel cycle performance analysis of fluoride and chloride fuels in Molten Salt Fast Reactor (MSFR)
Cammi, A.;
2023-01-01
Abstract
The signification of fast breeder reactors as an inexhaustible source of energy has been elucidated by many researchers. Molten Salt Reactors (MSRs) show great promise in fuel cycle performance. Fuel selection for MSRs is a key parameter due to its effect on many fundamental parameters of neutronic, safety, and fuel cycle through the neutron spectrum changes. choosing the fuel for MSRs has many degrees of freedom due to the variety of salts, carrier salts, and fissile and fertile isotope types. The foremost objective of this paper is a comparison of performance of fluoride and chloride fuels with the Th-U cycle for Molten Salt Fast Reactor (MSFR) concept. For this purpose, six fuels with start-up fissile isotopes of 233U, TRansUranium (TRU), and TRU/enrU are modeled by Monte Carlo Serpent 2 code. According to the MSFR design, the fuel compositions of three fluoride fuels are chosen from different conceptual designs. Chloride fuels, however, are selected based on the limit of the maximum melting point of salts (565 degrees C), criticality at the beginning of the cycle (BOC), and inherent safety criteria (temperature reactivity coefficients). The most important evaluated parameters include the energy spectrum, absorption and fission reaction rate, kinetic parameters, temperature reactivity coefficients, power density distribution, breeding ratio, and inventory changes of important isotopes during the burnup cycle. The results reveal neutron spectrum is less fast with fluoride salt; in contrast neutron leakage of chloride fuels are more than fluoride fuels due to their harder spectrum and transparency. Furthermore, the high leakage reduces the neutron budget required for breeding 232Th to 233U and the low density of chloride fuels causes a lower loading of fissile and fertile isotopes in the reactor. Therefore, using chloride fuels leads to larger core volume and need a proper reflector to reduce neutron leakage; Anyway, the U-Pu cycle shows better indications of the breeding for chloride fuels than the Th-U cycle. By the way corrosion and radioactivity of generated elements in chloride fuel circuit are serious problems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
