A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmut...A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β-decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR(PWR) and FBR(MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals(44Ru by FBR,46 Pd by LWR) and rare earth(64Gd by LWR,66 Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z(= Z + 1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element σc Z defined in this work. General trends of the creation rate of an even(odd) Z element from the corresponding odd(even) Z one were found to be proportional to the 0.78th(0.63th) power of σc Z, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.展开更多
The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin appr...The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin approximation. The a decay barriers have been determined in the quasimolecular shape path within a generalized liquid drop model including the proximity effects between nuclei in a neck, the mass and charge asymmetry and the precise nuclear radius. These calculations provide reasonable estimates for the observed a decay lifetimes. The calculated results have been compared with the results of the density-dependent M3Y effective interaction and the experimental data. It is indicated that the theoretical foundation of the generalized liquid drop model is as good as that of the microscopic DDM3Y model, at least in the sense of predicting the T1/2 values as long as one uses a correct a decay energy. The half lives of these new nuclei are well tested from the consistence of the macroscopic, the microscopic and the experimental data.展开更多
A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed b...A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed by replacing the internal gas with an equivalent solid in the modeling,which can make it convenient to simulate the thermal-mechanical coupling effects in the solid research objects with gases in them.The applied thermal expansion coefficient,Young's modulus and Poisson's ratio of the equivalent solid material are derived.A series of tests have been conducted;and the proposed equivalent solid method to simulate the gas effects is validated.展开更多
用235U诱发裂变径迹法对地幔岩捕虏体中铀的分布、含量及存在状态进行了详细的镜下径迹统计,以揭示铀元素在地幔岩中的种种存在状态和分布规律。在此基础上进一步把铀作为不相容元素群的示踪剂(tracer),指示地幔流体在深部地幔岩中的活...用235U诱发裂变径迹法对地幔岩捕虏体中铀的分布、含量及存在状态进行了详细的镜下径迹统计,以揭示铀元素在地幔岩中的种种存在状态和分布规律。在此基础上进一步把铀作为不相容元素群的示踪剂(tracer),指示地幔流体在深部地幔岩中的活动轨迹。结果表明,地幔流体能够渗透到各造岩矿物颗粒间隙、浆胞、蚀变边和晶体内部超微裂隙之中(此裂隙宽度很小,约为0.00 n^0.0 n mm)。地幔流体残渣呈极易浸出的非矿物形式的烃碱性物质吸附在超微裂隙之中(浸泡液pH>10)。通过浸泡结果能够大体窥知当初地幔流体的可能地球化学成分。展开更多
文摘A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β-decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR(PWR) and FBR(MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals(44Ru by FBR,46 Pd by LWR) and rare earth(64Gd by LWR,66 Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z(= Z + 1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element σc Z defined in this work. General trends of the creation rate of an even(odd) Z element from the corresponding odd(even) Z one were found to be proportional to the 0.78th(0.63th) power of σc Z, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.
基金Supported by the Major State Basic Research and Development Programme of China under Contract No G2000077400, the National Natural Science Foundation of China under Grant Nos 10505016, 10235020, 10235030, 10275094, 10075080 and 10575119, the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-SW-N02, National Key Programme for Basic Research of the Ministry of Science and Technology under Grant Nos 2001CCB01200 and 2002CCB00200, and the DFG of Germany.
文摘The lifetimes of a decays of the recently produced isotopes of the elements 112, 114, 116 and the element ^294118 and of some decay products have been calculated theoretically within the Wentzel-Kramers-Brillouin approximation. The a decay barriers have been determined in the quasimolecular shape path within a generalized liquid drop model including the proximity effects between nuclei in a neck, the mass and charge asymmetry and the precise nuclear radius. These calculations provide reasonable estimates for the observed a decay lifetimes. The calculated results have been compared with the results of the density-dependent M3Y effective interaction and the experimental data. It is indicated that the theoretical foundation of the generalized liquid drop model is as good as that of the microscopic DDM3Y model, at least in the sense of predicting the T1/2 values as long as one uses a correct a decay energy. The half lives of these new nuclei are well tested from the consistence of the macroscopic, the microscopic and the experimental data.
基金Supported by Natural Science Foundation of China(Nos.10772049 and 11072062)Research and Development Program of China(863 Program, No.2009AA04Z408)+1 种基金Natural Science Foundation of Shanghai(No.06ZR14009)Pujiang Scholar Program and the Wangdao Scholar Program(No.08076) of Fudan University
文摘A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed by replacing the internal gas with an equivalent solid in the modeling,which can make it convenient to simulate the thermal-mechanical coupling effects in the solid research objects with gases in them.The applied thermal expansion coefficient,Young's modulus and Poisson's ratio of the equivalent solid material are derived.A series of tests have been conducted;and the proposed equivalent solid method to simulate the gas effects is validated.
文摘用235U诱发裂变径迹法对地幔岩捕虏体中铀的分布、含量及存在状态进行了详细的镜下径迹统计,以揭示铀元素在地幔岩中的种种存在状态和分布规律。在此基础上进一步把铀作为不相容元素群的示踪剂(tracer),指示地幔流体在深部地幔岩中的活动轨迹。结果表明,地幔流体能够渗透到各造岩矿物颗粒间隙、浆胞、蚀变边和晶体内部超微裂隙之中(此裂隙宽度很小,约为0.00 n^0.0 n mm)。地幔流体残渣呈极易浸出的非矿物形式的烃碱性物质吸附在超微裂隙之中(浸泡液pH>10)。通过浸泡结果能够大体窥知当初地幔流体的可能地球化学成分。
