共查询到20条相似文献,搜索用时 15 毫秒
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采用浓盐酸溶解ThO_2和U_3O_8、以Dowex1×8阴离子交换树脂和Dowex50×8阳离子交换树脂作离子交换剂,研究了从大量钍及微量裂变产物(FPs)中提取微量铀的方法。考察了裂变产物元素Cs、Sr、Y、Zr、Nb、Ru、Rh、La、Ce、Eu的去污效果。结果表明,用离子交换法可以实现从百克每升Th及FPs中分离出微量U。最优工艺条件是料液调至8mol/L HCl介质,大量Th和微量的FPs在8mol/L HCl-0.2mol/L NH4F洗涤条件下直接通过阴离子交换柱,而U吸附于树脂上,再用0.05mol/L HNO_3淋洗U。低HNO_3淋洗U后,直接过阳离子柱吸附微量Th,再用2mol/L HNO_3淋洗得到纯U。结果表明,U收率大于98%,产品中Th及FPs的含量均小于0.05μg/L。 相似文献
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《中国原子能科学研究院年报(英文版)》2001,(1)
The apparatus is shown in Fig.1, which is mounted within a conventional metal bell jar 45 cm in diameter and 70 cm high. The boat source could be seen through the windows of the appratus and the bell jar.There was no straight-line exit from the apparatus to the interor of the bell jar for Be vapor originating at the boat.Tantalum boat, 13 mm wide, 28 mm long, and 0.1 mm thick, was used as evaporation source. The distance from the boat to the substrate was 15 cm. Microscope glass slide coated with betaine as substrate.The Be foils produced by resistance heating were removed from the glass by dissolving the 相似文献
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《中国原子能科学研究院年报(英文版)》2001,(1)
Metal sodium has an active chemical quality. When it is used as a coolant in a fast neutron reactor, it must be protected by a cover gas argon for safety operation of the reactor. But oxygen and water in argon can produce chemical reaction with sodium. Then sodium hydroxide, sodium oxide and hydrogen can be produced. This will be harmful to the safety operation of reactor. The purpose of controlling a level of impurity in the cover gas is for controlling a level of impurity in sodium. The research is to find an on-line determining method and a sampling system to monitor 相似文献
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Sahibzada Tasveer Muhammad Siraj-ul-Islam AhmadKhurrum Saleem Chaudri Ammar Ahmad 《Annals of Nuclear Energy》2008
The article deals with beryllium reflector effects on criticality of a miniature neutron source reactor, and the study of these effects for various cross-section evaluations. D-shape plates of beryllium are added on top of the reactor core to enhance reactivity of the system during operation. Fuel cycle analysis was carried out using SARC code. It was observed that reactivity effects of a particular thickness of beryllium remain nearly same during the whole life of the core. Up to 11% differences were observed between measured and calculated results for various libraries. The nearest match with the measured results was found for JENDL-3.2 library having maximum deviation of 5%. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):453-464
Pulsed neutron experiments in beryllium have been analyzed by the method of inelastic scattering expansion. Considering the full range of energy, the present method is applied to the calculation of the time dependent spectra within a system as well as at its surface. For obtaining the decay curve of the neutron counting rate, the neutrons are classified according to the number of specified inelastic scatterings that scatter the neutrons over the Bragg cutoff energy. The pseudo mode is, as a principal result, shown to correspond to an eigen solution of the thermal bounded equation. The buckling dependence of the eigenvalue and the eigen spectrum of the thermal bounded equation are studied, and useful approximate expressions are derived. The calculated results are compared with the experiments by Fullwood et al. and other authors. 相似文献
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X射线法测试铍材表层应力沿深度的分布 总被引:1,自引:1,他引:1
X射线应力分析是一种基于X射线衍射原理的无损应力检测方法,应用于铍材时,由于铍的密度低以及对X射线质量吸收系数小,X射线对铍材有较大穿透深度,因此,X射线法可以测试铍材表层一定深度内的应力.由于铍材表层应力分布往往不均匀,常规X射线应力分析法测试铍材应力存在误差,无法得到沿深度的应力分布.本工作根据常规X射线应力分析时不同侧倾角ψ下X射线穿透深度的不同,建立了一种适于铍材表层应力沿深度分布的测试方法,并用悬臂梁加载实验验证了该方法的可行性. 相似文献
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Shin Kajita Daisuke Nishijima Russ Doerner Karl Umstadter Jonathan Yu Noriyasu Ohno Yoshio Ueda 《Journal of Nuclear Materials》2012,420(1-3):252-257
Pulsed laser irradiation (~0.1–4 MJ/m2 at 1–10 ms) to a beryllium (Be) target has been performed under steady-state deuterium (D) plasma exposure in the linear divertor plasma simulator PISCES-B to investigate the response of Be to transient heat loads such as edge localized modes. Emission intensities from Be atoms and beryllium deuteride (BeD) molecules are observed in front of the Be target by using two fast framing cameras simultaneously; those exhibit similar time evolution to each other, but spatial profiles are different. While the Be I light emission peaks just in front of the target, the BeD emission peaks away from the target. This indicates that Be atoms are directly ejected from the surface, and BeD molecules are volumetrically formed in the plasma. It is also found that the time evolution of light emission can be qualitatively well reproduced by the evaporation flux of Be atoms, estimated from the calculated surface temperature. The Be surface is thought to be eroded as atoms due mainly to evaporation during laser irradiation. 相似文献
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介绍了多气隙电阻板室(MRPC)的结构和原理,用蒙特卡罗方法计算了MRPC对快中子的灵敏度,并进行了脉冲中子实验。实验表明,MRPC有望用于飞行时间法测量快中子能谱。 相似文献
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痕量镎和钚的ICP-MS分析方法 总被引:2,自引:0,他引:2
经TOA萃取色层柱分离环境样品,2次上柱,将Np和Pu同时洗脱,239Pu的化学回收率为 (92.7±3.1)%,237Np为(96.8±2.7)%,实现了ICP-MS同时测定痕量Np和Pu的含量.应用稀释剂242Pu,通过同位素稀释ICP-MS法测量痕量239Pu和240Pu的含量,用IAEA标样对方法进行验证,Pu 的测定值与标样的推荐值吻合较好(标样中无Np的标准值),证明了ICP-MS同时测定痕量Np和Pu的可行性. 相似文献
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《中国原子能科学研究院年报(英文版)》2000,(1)
237Nphasbeentraditionaldeterminedbyalphaspectrometryandneutronactivationana-lysis(NAA).Butthesemethodshavesomedisadvantages.Forinstance,α-spectrometryde-mandsahigherdegreeorradiochemicalpurityof237Nptoavoidinterferencefrom234U,231Paand230Th.Itneedsthepre… 相似文献
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《Journal of Nuclear Science and Technology》2013,50(11):461-470
Making use of a model based on the statistical theory, calculations were performed to obtain the mass yields, the most probable charges, the kinetic energies and the prompt neutron yields of fission fragments, and the mass yields of fission products from thermal-neutron-induced fission of 233U, 235U, 239Pu, 241Pu and from the spontaneous fission of 252Cf. The calculations are further extended to fast-neutron-induced fission. The scission-point distance is treated as a parameter varying with the mass number of the heavy fragments of fission. This proved successful in approaching the calculated curves closer to the observed values. It is possible to predict unknown physical quantities in nuclear fission with use made of the method developed in the present work. 相似文献