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对铀浓缩厂产品丰度的监测是核保障监督和军控核查的重要监测内容。在线铀丰度测量技术是对铀浓缩厂产品端管道UF6气体^235U丰度连续监测的一项技术。通过在线监测铀丰度,可有效地对铀浓缩厂进行核材料衡算核实和监视,节约核查人力和资源,并可判断铀浓缩厂是否有高浓铀的生产活动,是国际公认的一种有效的针对铀浓缩厂的核查措施。 相似文献
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铀丰度在线测量技术是用于铀浓缩厂产品端对管道内UF6气体中235U丰度连续监测的一项技术。通过在线监测铀丰度,可有效地对铀浓缩厂进行核材料衡算核实和监测,节约核查人力和资源,并可判断铀浓缩厂是否有高浓铀生产活动,是国际公认的一种针对铀浓缩厂核查的有效措施。 相似文献
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铀丰度在线监测仪是对铀浓缩厂工艺管道中UF6气体235U丰度进行在线监测的装置,本底是其核心关键技术指标,直接关系到丰度值的测量精度。原有本底测量方法需监测仪停止工作,人工将容器内的气体抽空进行测量。而本底自动测量方法通过改变测量容器内UF6气体的压力,用Na I(TI)探测器测量容器内UF6气体中235U发射的特征γ射线,利用压力传感器测量容器内UF6气体的压力值,最后对不同压力下的数据进行拟合获得监测仪的本底。实验结果表明,采用本底自动测量方法,监测仪铀丰度在线监测结果的相对标准偏差小于0.30%,与气体质谱计测量结果的最大相对偏差小于0.25%,表明该方法测量本底的准确度高;监测仪本底测量由软件自动完成,提高了监测仪的自动化程度,增强了监测仪的适用性。 相似文献
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研制了铀浓缩厂产品端UF6气体235U丰度在线实时监测装置。该装置由NaI(Tl)探测器、脉冲处理器、压力和温度传感器、管道阀门系统等组成,利用NaI(Tl)探测器对测量容器内气态UF6中235U发射的特征γ射线进行测量来得到235U的量,利用传感器对气体温度、压力进行测量,根据理想气体状态方程得到UF6气体中U的总量,从而得到235U丰度。该装置现场应用实验表明:铀丰度在线监测结果相对标准偏差小于1%,与气体质谱计测量结果相对偏差小于1%。 相似文献
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【本刊2012年10月综合报道】美国核管会(NRC)于2012年9月25日向全球激光浓缩公司(GLE)颁发了激光铀浓缩设施的建设与运行联合许可证,从而准许该公司在北卡罗来纳州威尔明顿(Wilmington)建设一座商业激光铀浓缩设施。这份许可证准许全球激光浓缩公司使用激光铀浓缩技术将铀-235的丰度浓缩至最高8%。这座铀浓缩设施生产的低浓铀将被用于制造供商业核电机组使用的核燃料。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(11):1023-1025
A numerical analysis is presented on the diffusive separation behavior of a three-component gas mixture of 235UF6, 238UF6, and light gas in a gas centrifuge. The purpose of analysis was to examine the isotope separation performance of the centrifuge in the presence of light gases such as N2 and HF, which inevitably leak in from the atmosphere or accumulate from impurities contained in uranium hexafluoride. An approximate basic equation is used, which is almost the same as derived by T. Kai for a ternary system from a generalized form of the Stefan-Maxwell equations, taking account of the pressure diffusion in a rapidly rotating cylinder. The method has previously been proposed for application to counter-current centrifuges, which are characterized by stable axial flow in two concentric streams, assuming that the gas mixture is in thermo-dynamical equilibrium between the light gas and UF6 mixture. Calculations made using the above basic equation indicated that the separative power of the centrifuge is significantly lowered with increasing penetration of the light gas into the separative zone between the two concentric streams. The results of calculation are in fairly good agreement with previously reported theories over a wide range of light gas concentration. Measurements made using an experimental centrifuge equipped with scoop substantiated the foregoing trends indicated from calculation up to about 1 mol/o average concentration of light gas in the centrifuge cylinder. At higher concentrations, a more significant lowering of separative power by the presence of light gas was indicated from measurement than from calculation. 相似文献
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The chemical uranium enrichment using ion exchanger had been developed mainly in Japan, but now only the academic studies have been continued at Tokyo Tech. For the purpose of revaluation as the alternative production process of the low enriched uranium for nuclear power plants, the plant design and the non-proliferation aspects of redox ion exchange chemical uranium enrichment (Redox Ion Exchange Method) were studied.The conceptual design of a commercial enrichment plant with a scale of 1400 tSWU/Y was newly performed based on data reported. It is composed of seven enrichment units with two enrichment columns with an inner diameter of 6.5 m and a height of 11 m and redox systems. It is evaluated as having the site area of 97,200 m2 including the vacancy to double the production with subsidiary sections of pre-treatment and post-treatment of uranium or the like, a construction cost is 218 billion Japanese yen(JPY), and a cost per enrichment work is 18,000 JPY/kgSWU. As for the nuclear proliferation resistance of this process, it is suggested that the production of highly enriched uranium for weapon use is difficult from the view point of nuclear fission criticality and the lengthy equilibrium time mentioned as following. It is difficult to operate the enrichment plant for the production of highly enriched uranium of 50 wt% of 235U or higher, because the effective neutron multiplication factor (keff) in the enrichment columns becomes 1 or above depending on the enrichment conditions. And the required time for the production of highly enriched uranium of 90 wt% of 235U is estimated 10 thousands days or more, this means substantially impossible to get highly enriched uranium under the safeguard of IAEA by the Redox Ion Exchange Method.The Redox Ion Exchange Method is suggested to be a promising candidate for an alternative enrichment process to obtain low enriched uranium in the range 3-5 wt% 235U for nuclear power plant in the world. Furthermore, for the future prospective fuel cycle without UF6, new front-end system coupled with uranium from seawater and chemical enrichment is proposed. 相似文献
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用低浓缩铀靶代替高浓缩铀靶辐照进行99Mo、131I等医用放射性核素生产是一个必然的趋势。本文利用输运计算程序DRAGON研究了靶件235U富集度、中子注量率、辐照时间对99Mo、131I、90Sr、95Zr、239Pu等核素比活度变化的影响,以及不同235U富集度下裂变体系组成和总比活度的变化规律。计算结果表明,本文考察的10余种核素比活度的变化随辐照时间的不同而有所不同,其中99Mo、131I、147Nd和133Xe等核素的比活度可快速达到饱和,89Sr、103Ru、95Zr和141Ce等缓慢达到饱和,而99Tc、85Kr和90Sr、239Pu在计算时间内达不到饱和,但所有核素的比活度随时间的变化趋势与靶件235U富集度无关;99Mo、131I、90Sr、95Zr等核素的比活度均随靶件235U富集度提高而增加,而239Pu比活度则随着靶件富集度的减少而显著增加,提示改用低浓缩铀靶进行99Mo、131I等医用放射性核素生产时应特别关注239Pu带来的影响;核素比活度随中子注量率的增加而线性增加,且斜率基本相同;靶件辐照时间的改变不会明显影响裂变体系的组成,在低浓缩铀(235U含量≤20%)区域,靶件235U富集度对裂变体系的组成影响很小。 相似文献
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六氟化铀(UF_6)是核燃料循环系统中铀存储和铀浓缩的主要物质形式,UF_6极易与空气中的水反应生成氟化氢(HF)气体,对UF_6同位素丰度和HF浓度的监测可以为UF_6泄露事故和核保障监督提供可靠数据,对核安全有重要意义。目前,可调谐半导体激光吸收光谱技术(TDLAS)具有实时、快速测量的优点,广泛应用于气体浓度和同位素比率测量等方面。本文主要对TDLAS技术测量UF_6同位素丰度和HF浓度方法和最新研究进展进行综述,通过比较测量方法,分析提高测量精度和测量灵敏度的可行性,并对TDLAS在核安全领域的应用前景进行展望。 相似文献
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本工作研究了铀同位素的离子交换色谱浓缩过程,讨论和验证了带迁移过程中坪区消失前浓缩区、贫化区同位素浓度分布分别与穿透、反穿透过程中的浓缩区、贫化区同位素浓度分布相同的观点:提出用三角形面积近似计算总富集量,并由此引入了校正塔板高度的概念,给出了铀同位素浓缩过程中主要参数间相互关系的几个公式,并做了实验验证。 相似文献
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γ能谱法测定高浓铀样品年龄 总被引:4,自引:2,他引:2
建立了用γ能谱法测定铀年龄的方法,用低本底高分辨γ谱仪通过测定214Bi/234U活度比得到高浓铀样品的龄.由于采用了内部效率自刻度,因此,该方法不受样品物理形态和几何形状的限制,也不需要用标准样品对系统进行效率刻度.对硝酸铀酰样品的铀年龄测量结果为18.00(4.1%)年,与样品实际年龄的相对偏差为-4.8%,误差主要来源于234U/235U比值的测量误差. 相似文献