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B. N. Laskorin V. S. Ul'yanov R. A. Sviridova A. M. Arzhatkin A. I. Yuzhin 《Atomic Energy》1961,7(2):620-625
Chromatographic methods of separating elements with very similar properties have now been developed. However, a number of these methods are difficult to use industrially as their throughput is low. The efficiency of chromatographic separation methods could be increased considerably by using appropriate complex formers, which decrease the effective concentration of the ions being separated, and,in the first approximation, this is equivalent to a decrease in the amount of elements being separated. The difference in the formation constants of the complex compounds increases the separation coefficient. By investigating chromatographic separation with the use of various complex formers, we found the optimal conditions for separating barium and radium, zirconium and hafnium, and aluminum and gallium. The throughput of these methods, with respect to the macroelement was 15–60 kg/hr per m2 of column cross section. 相似文献
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随着核与辐射技术在医学检查、诊断和治疗领域运用的增加,世界范围受照人群不断增多,医源性辐射已成为人类最主要的人工辐射来源之一。医疗机构和个人在选择利用放射手段获取诊断和治疗利益的同时,需要注意和防护伴随的辐射损伤效应。本文介绍了医源性辐射及其危害、机体组织的辐射损伤特性和类型、辐射生物效应分子及效应调节研究的进展,简要概述目前临床已经使用或最具应用潜力的辐射防护策略。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):284-291
The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (K Cs>103 cm3·g?1) in the presence of NaCl (10?1 mol·dm?3). The K Sr values for zeolite A attained about 103 cm3·g?1 in the pH range of 8~10, and they gradually decreased with an decrease in pH. The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAlSi2O6) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl2Si2O6 above 900°C. These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions. 相似文献
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清洁解控和退役若干动向与新发展 总被引:2,自引:0,他引:2
对国际辐射防护协会第 1 0届大会 ( IRPA-1 0 )涉及的清洁解控和退役问题作了论述 ,包括排除、豁免、清洁解控和废物最少化 ;退役工程技术的发展 ,包括去污技术、切割解体技术、探测技术 ;介绍了一个研究堆退役例子和加速器退役 ;最后 ,还论及了退役中受关注的一些问题 ,如 :石墨废物、混凝土废物、重水堆退役的氚防护、退役时间和退役废物量等。 相似文献
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A. Chrysochoos O. Maisonneuve G. Martin H. Caumon J.C. Chezeaux 《Nuclear Engineering and Design》1989,114(3)
This paper depicts one theoretical and experimental method to take into account the energy phenomena, associated with the elasto—plastic deformation process, during the elaboration of behaviour laws. The energy balance definition is examined in order to relate the stored energy of cold work to the hardening state variables. Two experimental approaches are used to study the evolution of the energy balance. The first one uses microcalorimetric technique and the second infrared technique. Several industrial metallic materials are studied by both approaches. Energy data are used to control the validity domain of the classical behaviour laws and to elaborate new more appropriate ones. Therefore, the hardening parameters cannot be identified with the thermodynamical forces. The use of energy considerations allows the definition of new thermodynamical forces and state variables, in the case of isotropic or kinematical hardening. 相似文献
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Hui-Wen Huang Author Vitae Chunkuan Shih Ming-Huei Chen 《Nuclear Engineering and Design》2009,239(6):1136-1147
This work developed an advanced boiling water reactor (ABWR) feedwater pump and controller model, which was incorporated into Personal Computer Transient Analyzer (PCTran)-ABWR, a nuclear power plant simulation code. The feedwater pump model includes three turbine-driven feedwater pumps and one motor-driven feedwater pump. The feedwater controller includes a one-element/three-element water level controller and a specific feedwater speed controller for each feedwater pump. The performance tests, including step change of dome pressure, feedwater pumps transfer, inadvertent closure of all turbine control valves, and one feedwater pump trip at 100% power, demonstrate the feasibility of dynamic response of stand-alone model and incorporated model. Furthermore, a diversity and defense-in-depth analysis is performed to demonstrate the feasibility for motor-driven feedwater pump as an emergency core cooling system (ECCS) automatic diverse back-up. In Lungmen nuclear power plant (NPP), a diverse manual initiation means for the high pressure core flooder (HPCF) loop C is designed as the back-up of digitalized engineered safety features actuation system (ESFAS). If the motor-driven feedwater pump (MDFWP) can be an automatic digital diverse back-up for ESFAS, Lungmen NPP would be more robust to defend against software common-cause failure (CCF). 相似文献
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Past experience with small and medium power reactors (SMPRs) in the areas of construction and operation is examined in this paper. Current development of SMPRs focuses on passive safety features; larger design and safety margins; reduction of construction periods through simplification, modularization and increased shop fabrication. 相似文献
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Hasan H. Durmazuar Üner olak Bar
Sarkaya Güngr Gündüz 《Nuclear Engineering and Design》2001,203(1):57
In this research the burnup performance of (1) boron nitride (BN) and (2) boron nitride-boron (B), hybrid coated urania (UO2) and urania-gadolinia (Gd2O3) fuels were studied. The behavior of fuel burnup, depletion of BN and B, the effect of coating thickness and also Gd2O3 content on the burnup performances of the fuels were found by using the code WIMS-D/5 for pressurized water reactor (PWR) and boiling water reactor (BWR) fuel assemblies. The optimum thickness ratio of B to BN was found as 4 and their thicknesses were chosen as 4 and 1 μm, respectively. Based on this observation, calculations were performed for the standard fuel assemblies with and without burnable poison and similar assemblies with BN-B hybrid coating with the desired BN-B thicknesses. Results are discussed to make an assessment of the effect of such hybrid coating on fuel cycle characteristics. 相似文献
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核电站反应堆测温热电偶回收装置是堆芯热电偶检修、更换、回收的专用设备。本文结合300MW反应堆型,介绍了一种结构简单、操作方便、使用安全可靠的热电偶拔出回收技术及回收处理装置。 相似文献
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《中国原子能科学研究院年报(英文版)》2016,(0)
正2016 was the opening year of the 13~(th) Fiveyear Plan.Under the auspices of relevant state departments and the direct leadership of the China National Nuclear Corporation(CNNC),the China Institute of Atomic Energy(CIAE),strictly followed the guidance of"improving the awareness 相似文献
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Yuji Ohishi Mitsuyuki Sugizaki Yifan Sun Hiroaki Muta Ken Kurosaki 《Journal of Nuclear Science and Technology》2019,56(9-10):859-865
ABSTRACTFuel debris in the Fukushima Daiichi nuclear power plant is thought to contain borides that are generated from B4C control material. In order to successfully devise methods to effectively remove the debris material, characterization of the properties of the fuel debris is essential. This paper presents some of the thermophysical and mechanical properties of two types of borides, FeB and CrB, and compares them with those of Fe2B and ZrB2. These are the representative borides that might have been generated in the Fukushima Daiichi (1F) nuclear power plant accident. We observed that the thermal conductivity values of both CrB and FeB are much lower than that of ZrB2, and are similar to that of Fe2B. Moreover, the Vickers hardness and fracture toughness of FeB and CrB are almost identical to each other, and similar to those of ZrB2 and Fe2B. 相似文献
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G. N. Flerov 《Atomic Energy》1969,26(2):160-164
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面对公众对核与辐射风险极度敏感的现象,本文阐述了对风险的认知及影响认知程度的因素,介绍了风险沟通的发展阶段和四种类型,并给出了若干有效的风险沟通策略建议。 相似文献
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David M. Parks 《Nuclear Engineering and Design》1987,105(1)
In recent years, several important advances in the understanding of the mechanics and mechanisms of creep deformation, damage and fracture in polycrystalline alloys have been achieved through the synergistic efforts of materials scientists and applied mechanicians. Current understanding, while far from complete, nonetheless provides a physically-based framework for developing computationally tractable continuum constitutive relations which capture major features of the intrinsic mechanisms of creep damage and deformation. Such models, when applied to the analysis of scientifically and technologically relevant boundary value problems, provide a basis for a local approach to high temperature fracture. The first section of the paper reviews certain aspects of the phenomenology, mechanisms, and mathematical models of creep fracture. It is concluded that an important internal damage parameter influencing macroscopic tertiary creep in conventional polycrystalline materials is the density of grain boundary facet cracks. The development of a “damage” constitutive model can conceptually be broken into two parts. One aspect is to quantify the effect of an (instantaneous) state of damage on the mechanical behavior. In the second part of the paper, this topic is explored for the case of a (generally non-dilute) distribution of aligned facet cracks in a power law creeping matrix. The remaining aspect of the model is to provide evolution equations for the damage variable(s). In the third section of the paper, we develop a simplified model for the evolution of facet crack density under conditions of creep-constrained cavitation. A central feature of the model is the variability in cavity nucleation potency over the grain boundary population. 相似文献