Abstract： The pre-neutron-emission mass distributions for reaction ^238U（n, f） up to 60 MeV are systematically studied with an empirical fission potential model. The energy dependence of the peaks and valleys of th...Abstract： The pre-neutron-emission mass distributions for reaction ^238U（n, f） up to 60 MeV are systematically studied with an empirical fission potential model. The energy dependence of the peaks and valleys of the pre-neutronemission mass distributions is described by an exponential form based on the newly measured data. The energy dependence of evaporation neutrons before scission is also considered, which plays a crucial role in the reasonable description of the mass distributions. The measured ^238U（n, f） are reasonably well reproduced up to 60 predicted using this approach. data of the pre-neutron-emission mass distributions for reaction MeV. The mass distributions at unmeasured energies are also展开更多
In order to check the conceptual design of the subcritical blanket in a fusion-fission hybrid reactor, a depleted uranium/polyethylene simulation device with alternate shells has been established. The measurement of t...In order to check the conceptual design of the subcritical blanket in a fusion-fission hybrid reactor, a depleted uranium/polyethylene simulation device with alternate shells has been established. The measurement of the 23SU（n, 2n） reaction rate was carried out using an activation technique, by measuring the 208 keV T rays emitted from 237U. The self-absorption of depleted uranium foils with different thicknesses was experimentally corrected. The distribution of the 23SU（n, 2n） reaction rate at 90° to the incident D＋ beam was obtained, with uncertainty between 5.3% and 6.0%. The experiment was analyzed using MCNP5 code with the ENDF/BVI library, and the calculated results are all about 5% higher than the measured results.展开更多
Properties of prompt fission neutrons from 238U（n, f） are calculated for incident neutron egies below 6 MeV using the multi-modal model, including the prompt fission neutron spectrum, thnere average prompt fission n...Properties of prompt fission neutrons from 238U（n, f） are calculated for incident neutron egies below 6 MeV using the multi-modal model, including the prompt fission neutron spectrum, thnere average prompt fission neutron multiplicity, and the prompt fission neutron multiplicity as a function of the fission fragment mass v（A） （usually named ＂sawtooth＂ data） The three most dominant fission modes are taken into account. The model parameters are determined on the basis of experimental fission fragment data. The predicted results are in good agreement with the experimental data.展开更多
Production of light complex particles from the n＋^238u reaction is analyzed with the exciton model including the improved Iwamoto-Harada pickup mechanism for the preequilibrium process. It is allowed that some of the...Production of light complex particles from the n＋^238u reaction is analyzed with the exciton model including the improved Iwamoto-Harada pickup mechanism for the preequilibrium process. It is allowed that some of the nucleons forming the complex ejectile come from levels below the Fermi energy, and the intrinsic structure of the emitted particle is taken into account. The equilibrium-state emissions are also considered by using Hauser- Feshbach theory with the width fluctuation correction and the evaporation model angular distributions, energy spectra and double differential cross sections of neutron, alpha emissions for the n＋^238U reaction are consistently calculated and analyzed with the energy range En ≤150 MeV. ENDF-formatted nuclear data including information charged particles are obtained. Moreover, all cross sections, proton, deuteron, triton and nuclear theoretical models in about the production of light展开更多
核数据不确定性分析影响着反应堆安全,在反应堆堆芯物理计算过程中具有重要意义。利用SCALE6.1程序包中KENO模块建立反应堆模拟评估和验证基准BEAVRS(Benchmark for Evaluation and Validation of Reactor Simulations)第一循环热态零...核数据不确定性分析影响着反应堆安全,在反应堆堆芯物理计算过程中具有重要意义。利用SCALE6.1程序包中KENO模块建立反应堆模拟评估和验证基准BEAVRS(Benchmark for Evaluation and Validation of Reactor Simulations)第一循环热态零功率堆芯物理模型,采用TSUNAMI-3D模块开展k_(eff)的敏感性与不确定性分析,分析了不同燃料富集度、不同温度对k_(eff)敏感性与不确定性的影响。结果表明:核数据不确定性导致BEAVRS模型的k_(eff)总的不确定性为0.5016%;^(235)U的平均裂变中子数敏感性导致k_(eff)的敏感性系数最大(0.92658);对k_(eff)不确定性贡献最大的是238U(n,γ)反应截面,为0.29814%;在燃料富集度降低、温度上升时,238U(n,γ)反应截面不确定性会导致k_(eff)的不确定性增大。因此,在开展反应堆堆芯物理计算过程中,应重点关注238U(n,γ)反应截面信息。展开更多
基金Supported by Guangxi University Science and Technology Research Projects(2013ZD007)Guangxi Natural Science Foundation(2012GXNSFAA053008)National Natural Science Foundation of China(11265004)
文摘Abstract： The pre-neutron-emission mass distributions for reaction ^238U（n, f） up to 60 MeV are systematically studied with an empirical fission potential model. The energy dependence of the peaks and valleys of the pre-neutronemission mass distributions is described by an exponential form based on the newly measured data. The energy dependence of evaporation neutrons before scission is also considered, which plays a crucial role in the reasonable description of the mass distributions. The measured ^238U（n, f） are reasonably well reproduced up to 60 predicted using this approach. data of the pre-neutron-emission mass distributions for reaction MeV. The mass distributions at unmeasured energies are also
基金Supported by Chinese Special Project for ITER (2010GB111002)
文摘In order to check the conceptual design of the subcritical blanket in a fusion-fission hybrid reactor, a depleted uranium/polyethylene simulation device with alternate shells has been established. The measurement of the 23SU（n, 2n） reaction rate was carried out using an activation technique, by measuring the 208 keV T rays emitted from 237U. The self-absorption of depleted uranium foils with different thicknesses was experimentally corrected. The distribution of the 23SU（n, 2n） reaction rate at 90° to the incident D＋ beam was obtained, with uncertainty between 5.3% and 6.0%. The experiment was analyzed using MCNP5 code with the ENDF/BVI library, and the calculated results are all about 5% higher than the measured results.
基金Supported by State Key Development Program for Basic Research of China (2008CB717803,2009GB107001,2007CB209903)Research Fund for the Doctoral Program of Higher Education of China (200610011023)
文摘Properties of prompt fission neutrons from 238U（n, f） are calculated for incident neutron egies below 6 MeV using the multi-modal model, including the prompt fission neutron spectrum, thnere average prompt fission neutron multiplicity, and the prompt fission neutron multiplicity as a function of the fission fragment mass v（A） （usually named ＂sawtooth＂ data） The three most dominant fission modes are taken into account. The model parameters are determined on the basis of experimental fission fragment data. The predicted results are in good agreement with the experimental data.
基金Supported by National Natural Science Foundation of China-NSAF(U1630122)IAEA Coordinated Research Projects(CRPs)on Recommended Input Parameter Library(RIPL)for Fission Cross Section Calculations(20464)Science Challenge Project(TZ2018005)
文摘Production of light complex particles from the n＋^238u reaction is analyzed with the exciton model including the improved Iwamoto-Harada pickup mechanism for the preequilibrium process. It is allowed that some of the nucleons forming the complex ejectile come from levels below the Fermi energy, and the intrinsic structure of the emitted particle is taken into account. The equilibrium-state emissions are also considered by using Hauser- Feshbach theory with the width fluctuation correction and the evaporation model angular distributions, energy spectra and double differential cross sections of neutron, alpha emissions for the n＋^238U reaction are consistently calculated and analyzed with the energy range En ≤150 MeV. ENDF-formatted nuclear data including information charged particles are obtained. Moreover, all cross sections, proton, deuteron, triton and nuclear theoretical models in about the production of light
文摘核数据不确定性分析影响着反应堆安全,在反应堆堆芯物理计算过程中具有重要意义。利用SCALE6.1程序包中KENO模块建立反应堆模拟评估和验证基准BEAVRS(Benchmark for Evaluation and Validation of Reactor Simulations)第一循环热态零功率堆芯物理模型,采用TSUNAMI-3D模块开展k_(eff)的敏感性与不确定性分析,分析了不同燃料富集度、不同温度对k_(eff)敏感性与不确定性的影响。结果表明:核数据不确定性导致BEAVRS模型的k_(eff)总的不确定性为0.5016%;^(235)U的平均裂变中子数敏感性导致k_(eff)的敏感性系数最大(0.92658);对k_(eff)不确定性贡献最大的是238U(n,γ)反应截面,为0.29814%;在燃料富集度降低、温度上升时,238U(n,γ)反应截面不确定性会导致k_(eff)的不确定性增大。因此,在开展反应堆堆芯物理计算过程中,应重点关注238U(n,γ)反应截面信息。
