In this study,COMSOL v5.2 Multiphysics software was utilized to perform coupled neutronics and thermal–hydraulics simulations of a molten salt fast reactor,and the SCALE v6.1 code package was utilized to generate the...In this study,COMSOL v5.2 Multiphysics software was utilized to perform coupled neutronics and thermal–hydraulics simulations of a molten salt fast reactor,and the SCALE v6.1 code package was utilized to generate the homogenized cross-section data library.The library’s 238 cross-section groups were categorized into nine groups for the simulations in this study.The results of the COMSOL model under no fuel flow conditions were verified using the SCALE v6.1 code results,and the results of the neutronics and thermal–hydraulics simulations were compared to the results of previously published studies.The results indicated that the COMSOL model that includes the cross-section library generated by the SCALE v6.1 code package is suitable for the steady-state analysis and design assessment of molten salt fast reactors.Subsequently,this model was utilized to investigate the neutronics and thermal–hydraulics behaviors of the reactor.Multiple designs were simulated and analyzed in this model,and the results indicated that even if the wall of the core is curved,hot spots occur in the upper and lower portions of the core’s center near the reflectors.A new design was proposed that utilizes a flow rate distribution system,and the simulation results of this design showed that the maximum temperature in the core was approximately 1032 K and no hot spots occurred.展开更多
The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the intera...The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dnEγ/d Inof the γ-ray transition energies in a△I = 2 and △I = 4 bands, which yielding multipoint formulae. The first order derivative(two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative(five-point formula) is about 0.5 Ke V and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes236,238 U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.展开更多
The shape transition between the vibrational U(5)and deformed c-unstable O(6)dynamical symmetries of sd interacting boson model has been investigated by considering a modified O(6)Hamiltonian,providing that the coeffi...The shape transition between the vibrational U(5)and deformed c-unstable O(6)dynamical symmetries of sd interacting boson model has been investigated by considering a modified O(6)Hamiltonian,providing that the coefficients of the Casimir operator of O(5)are N-dependent,where N is the total number of bosons.The modified O(6)Hamiltonian does not contain the number operator of the d boson,which is responsible for the vibrational motions.In addition,the deformation features can be achieved without using the SU(3)limit by adding to the O(6)dynamical symmetry the three-body interaction[QQQ]^(0),where Q is the O(6)symmetric quadrupole operator.Moreover,triaxiality can be generated through the inclusion of the cubic d-boson interaction[d+d+d+]^(3)·∣ddd∣^(3).The classical limit of the potential energy surface(PES),which represents the expected value of the total Hamiltonian in a coherent state,is studied and examined.The modified O(6)model is applied to the even–even^124-132 Xe isotopes.The parameters for the Hamiltonian and the PESs are calculated using a simulated search program to obtain the minimum root mean square deviation between the calculated and experimental excitation energies and B(E2)values for a number of low-lying levels.A good agreement between the calculations and experiment results is found.展开更多
文摘In this study,COMSOL v5.2 Multiphysics software was utilized to perform coupled neutronics and thermal–hydraulics simulations of a molten salt fast reactor,and the SCALE v6.1 code package was utilized to generate the homogenized cross-section data library.The library’s 238 cross-section groups were categorized into nine groups for the simulations in this study.The results of the COMSOL model under no fuel flow conditions were verified using the SCALE v6.1 code results,and the results of the neutronics and thermal–hydraulics simulations were compared to the results of previously published studies.The results indicated that the COMSOL model that includes the cross-section library generated by the SCALE v6.1 code package is suitable for the steady-state analysis and design assessment of molten salt fast reactors.Subsequently,this model was utilized to investigate the neutronics and thermal–hydraulics behaviors of the reactor.Multiple designs were simulated and analyzed in this model,and the results indicated that even if the wall of the core is curved,hot spots occur in the upper and lower portions of the core’s center near the reflectors.A new design was proposed that utilizes a flow rate distribution system,and the simulation results of this design showed that the maximum temperature in the core was approximately 1032 K and no hot spots occurred.
文摘The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dnEγ/d Inof the γ-ray transition energies in a△I = 2 and △I = 4 bands, which yielding multipoint formulae. The first order derivative(two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative(five-point formula) is about 0.5 Ke V and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes236,238 U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.
文摘The shape transition between the vibrational U(5)and deformed c-unstable O(6)dynamical symmetries of sd interacting boson model has been investigated by considering a modified O(6)Hamiltonian,providing that the coefficients of the Casimir operator of O(5)are N-dependent,where N is the total number of bosons.The modified O(6)Hamiltonian does not contain the number operator of the d boson,which is responsible for the vibrational motions.In addition,the deformation features can be achieved without using the SU(3)limit by adding to the O(6)dynamical symmetry the three-body interaction[QQQ]^(0),where Q is the O(6)symmetric quadrupole operator.Moreover,triaxiality can be generated through the inclusion of the cubic d-boson interaction[d+d+d+]^(3)·∣ddd∣^(3).The classical limit of the potential energy surface(PES),which represents the expected value of the total Hamiltonian in a coherent state,is studied and examined.The modified O(6)model is applied to the even–even^124-132 Xe isotopes.The parameters for the Hamiltonian and the PESs are calculated using a simulated search program to obtain the minimum root mean square deviation between the calculated and experimental excitation energies and B(E2)values for a number of low-lying levels.A good agreement between the calculations and experiment results is found.
