We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-...We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.展开更多
To validate neutronics calculation for the blanket design of fusion-fission hybrid reactor,experiments for measuring reaction rates inside two simulating assemblies are performed.Two benchmark assemblies were develope...To validate neutronics calculation for the blanket design of fusion-fission hybrid reactor,experiments for measuring reaction rates inside two simulating assemblies are performed.Two benchmark assemblies were developed for the neutronics experiments.A D-T fusion neutron source is placed at the center of the setup.One of them consists of three layers of depleted uranium shells and two layers of polyethylene shells,and these shells are arranged alternatively.The ^(238)U capture reaction rates are measured using depleted uranium foils and an HPGe gamma spectrometer.The fission reaction rates are measured using a fission chamber coated with depleted uranium.The other assembly consists of depleted uranium and LiH shells.The tritium production rates are measured using the lithium glass scintillation detector which is placed in the LiH region of the assembly.The measured reaction rates are compared with the calculated ones predicted using MCNP code,and C/E values are obtained.展开更多
Knowledge of actinides(n,f) fission process induced by neutron is of importance in the field of nuclear power and nuclear engineering,especially for reactor applications.In this work,fission characteristics of^(238)U(...Knowledge of actinides(n,f) fission process induced by neutron is of importance in the field of nuclear power and nuclear engineering,especially for reactor applications.In this work,fission characteristics of^(238)U(n,f) reaction induced by D-T neutron source were simulated with Geant4 code from multiple perspectives,including the fission production yields,total nubar,kinetic energy distribution,fission neutron spectrum and cumulative γ-ray spectrum of the fission products.The simulation results agree well with the experimental nuclear reaction data(EXFOR) and evaluated nuclear data(ENDF).Mainly,this work was to examine the rationality of the parametric nuclear fission model in Geant4 and to direct our future experimental measurements for the cumulative fission yields of ^(238)U(n,f) reaction.展开更多
The 230Ra has been produced via multinucleon transfer and dissipative fragmentation of heavy target in the 60 MeV/u 18O ion reaction with natural thorium. The radium was radiochemically separated from irradiated thori...The 230Ra has been produced via multinucleon transfer and dissipative fragmentation of heavy target in the 60 MeV/u 18O ion reaction with natural thorium. The radium was radiochemically separated from irradiated thorium targets. 230Ac was obtained by 230Ra β-→230Ac. Thin Ra sources were prepared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposed to the mica fission track detectors and measured by a HPGe γ detector. The two fission events were obtained and could been assigned to the β-delayed fission of 230Ac. The β-delayed fission probability of 230Ac was determined to be (1.19±0.85)×10-8.展开更多
A tokamak fusion-fission hybrid reatcor is proposed as one of candidates for disposal ofthe long-lived actinides and fission product wastes and supply of future energy.To assess thefeasibility of transmutation of long...A tokamak fusion-fission hybrid reatcor is proposed as one of candidates for disposal ofthe long-lived actinides and fission product wastes and supply of future energy.To assess thefeasibility of transmutation of long-lived radiowastes using fusion-fission hybrid reactors,afusion core design is presented and several possible conceptual blankets are studied,for,re-spectively,actinides transmutation and fission product transmutation.The results show thatactinides and fission products may be effectively transmuted using the presented hybrid reac-tors.展开更多
The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential...The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the 237 Np(n, f)reaction. Compared with the built-in G4 ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system.展开更多
The mean total kinetic energy as a function of fission fragments,the<TKE>distribution,is presented for neutron-induced fission of ^(235-239)Np using the scission point model.The calculated results of<TKE>f...The mean total kinetic energy as a function of fission fragments,the<TKE>distribution,is presented for neutron-induced fission of ^(235-239)Np using the scission point model.The calculated results of<TKE>for neutron-induced fission of ^(237,238) Np are compared with the available experimental data to obtain the deformation parameters in the scission point model.The deformation parameters of fission fragments are discussed at the scission point.The calculated results are also compared with the results from other methods and with experimental data.The behavior of the<TKE>distribution is then studied for the neutron-induced fission of actinides.This indicates that the<TKE>values for neutron-induced fission of actinides with odd mass numbers are greater than for those with even mass numbers.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11875174,11961131010,and 11961141004)the Polish National Science Center(No.2018/30/Q/ST2/00185)。
文摘We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.
基金supported by the National Special Magnetic Confinement Fusion Energy Research (No.2010GB111002),China
文摘To validate neutronics calculation for the blanket design of fusion-fission hybrid reactor,experiments for measuring reaction rates inside two simulating assemblies are performed.Two benchmark assemblies were developed for the neutronics experiments.A D-T fusion neutron source is placed at the center of the setup.One of them consists of three layers of depleted uranium shells and two layers of polyethylene shells,and these shells are arranged alternatively.The ^(238)U capture reaction rates are measured using depleted uranium foils and an HPGe gamma spectrometer.The fission reaction rates are measured using a fission chamber coated with depleted uranium.The other assembly consists of depleted uranium and LiH shells.The tritium production rates are measured using the lithium glass scintillation detector which is placed in the LiH region of the assembly.The measured reaction rates are compared with the calculated ones predicted using MCNP code,and C/E values are obtained.
基金supported by the National Natural Science Foundation of China(No.21327801)
文摘Knowledge of actinides(n,f) fission process induced by neutron is of importance in the field of nuclear power and nuclear engineering,especially for reactor applications.In this work,fission characteristics of^(238)U(n,f) reaction induced by D-T neutron source were simulated with Geant4 code from multiple perspectives,including the fission production yields,total nubar,kinetic energy distribution,fission neutron spectrum and cumulative γ-ray spectrum of the fission products.The simulation results agree well with the experimental nuclear reaction data(EXFOR) and evaluated nuclear data(ENDF).Mainly,this work was to examine the rationality of the parametric nuclear fission model in Geant4 and to direct our future experimental measurements for the cumulative fission yields of ^(238)U(n,f) reaction.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10425521, 10075002, and 10135030, the Major State Basic Research Development Programme under Grant No G2000077400, and Doctoral Program Foundation of the Ministry of Education of China under Grant No 20040001010, the Foundation for University Key Teacher by the Ministry of Education of China.
基金Supported by the National Natural Science Foundation of ChinaMajor State Basic Research Development Program, Chinese Aca
文摘The 230Ra has been produced via multinucleon transfer and dissipative fragmentation of heavy target in the 60 MeV/u 18O ion reaction with natural thorium. The radium was radiochemically separated from irradiated thorium targets. 230Ac was obtained by 230Ra β-→230Ac. Thin Ra sources were prepared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposed to the mica fission track detectors and measured by a HPGe γ detector. The two fission events were obtained and could been assigned to the β-delayed fission of 230Ac. The β-delayed fission probability of 230Ac was determined to be (1.19±0.85)×10-8.
基金the High Technology Research and Development Programme of china.
文摘A tokamak fusion-fission hybrid reatcor is proposed as one of candidates for disposal ofthe long-lived actinides and fission product wastes and supply of future energy.To assess thefeasibility of transmutation of long-lived radiowastes using fusion-fission hybrid reactors,afusion core design is presented and several possible conceptual blankets are studied,for,re-spectively,actinides transmutation and fission product transmutation.The results show thatactinides and fission products may be effectively transmuted using the presented hybrid reac-tors.
基金Supported by the National Natural Science Foundation of China(11705071,11875155,11675069,21327801)NSAF(U1830102)+2 种基金NSFC-Nuclear Technology Innovation Joint Fund(U1867213)the DSTI Foundation of Gansu(2018ZX-07)the Fundamental Research Funds for the Central Universities(lzujbky-2017-13,lzujbky-2018-bt09,lzujbky-2019-bt09)
文摘The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the 237 Np(n, f)reaction. Compared with the built-in G4 ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system.
文摘The mean total kinetic energy as a function of fission fragments,the<TKE>distribution,is presented for neutron-induced fission of ^(235-239)Np using the scission point model.The calculated results of<TKE>for neutron-induced fission of ^(237,238) Np are compared with the available experimental data to obtain the deformation parameters in the scission point model.The deformation parameters of fission fragments are discussed at the scission point.The calculated results are also compared with the results from other methods and with experimental data.The behavior of the<TKE>distribution is then studied for the neutron-induced fission of actinides.This indicates that the<TKE>values for neutron-induced fission of actinides with odd mass numbers are greater than for those with even mass numbers.
