Stainless steel-zirconium waste forms from the treatment of spent nuclear fuel

Stainless steel-zirconium waste-form alloys have been developed for the disposal of metallic wastes recovered from spent nuclear fuel using the electrometallurgical process developed by Argonne National Laboratory. The metal waste comprises the spent-fuel cladding, noble-metal fission products, and other metallic constituents remaining after electrorefining. Two nominal waste-form compositions have been slected: stainless steel-clad fuels and zirconium-8 wt.% stainless steel for Zircaloy-clad fuels. These alloys are very corrosion resistant. Tests performed with these alloys indicate favorable behavior for use high-level nuclear waste forms.     

基于氢微缩技术拉伸变形Al一9％Mg合金的晶界氢析出

近年来,诸如全球变暖、化石燃料枯竭等环境问题日趋严重。发展使用氢作为清洁能源的燃料电池汽车,受到了汽车制造商的广泛重视。铝合金已经应用到燃料汽车的高压氢气槽的衬垫材料中。然而,氢在铝合金中的反应仍然没有得到清楚的阐明。因此,有必要分析氢在铝合金中的反应。氢缩影技术（HMPT）一直被视为一种探讨铝合金中氢行为的有效措施。目前,在室温下采用HMPT技术研究了拉伸变形Al—9％Mg合金内部氢析出的过程,发现氢在一些晶界处析出。     

Chrome Core~系列耐蚀软磁合金的开发及应用

兼具优异磁性能和耐腐蚀的合金被广泛用于汽车和其他工业及消费品领域。如汽车喷油装置,油泵电机叠片,ABS系统和悬挂自动调节系统,以及电冰箱,洗衣机,电熨斗,咖啡壶,自动售货机的电磁阀等。也可用于任何暴露在轻化学介质下的电磁部件。具有软磁性能的同时,合金要有良好的耐蚀性,以满足各种腐蚀环境的应用要求。如汽车喷油装置须抗含甲醇/乙醇的燃油导致的腐蚀,以及其他应用条件下须抗较苛刻水溶液腐蚀,尤其是含氯离子导致的电磁阀缝隙腐蚀。简述了Chrome Core系列耐蚀软磁合金的开发研究,对其性能特点以及应用作了分析比较。     

Versatile Oxide Films Protect FeCrAl Alloys Under Normal Operation and Accident Conditions in Light Water Power Reactors

The US has currently a fleet of 99 nuclear power light water reactors which generate approximately 20% of the electricity consumed in the country. Near 90% of the reactors are at least 30 years old. There are incentives to make the existing reactors safer by using accident tolerant fuels (ATF). Compared to the standard UO₂–zirconium-based system, ATF need to tolerate loss of active cooling in the core for a considerably longer time while maintaining or improving the fuel performance during normal operation conditions. Ferritic iron-chromium-aluminum (FeCrAl) alloys have been identified as an alternative to replace current zirconium alloys. They contain Fe (base) + 10–22 Cr + 4–6 Al and may contain smaller amounts of other elements such as molybdenum and traces of others. FeCrAl alloys offer outstanding resistance to attack by superheated steam by developing an alumina oxide on the surface in case of a loss of coolant accident like at Fukushima. FeCrAl alloys also perform well under normal operation conditions both in boiling water reactors and pressurized water reactors because they are protected by a thin oxide rich in chromium. Under normal operation condition, the key element is Cr and under accident conditions it is Al.     

The Effect of Fuel Types on Porous Alumina Produced via Soft Combustion Reaction for Implant Applications

This article describes the effects of fuel types on the porous structure of alumina produced using a soft combustion reaction. There are several combustion parameters that could affect the porous structure of the alumina produced such as fuel-to-oxidizer ratios, ignition temperature, and type of fuels. In this study, the effect of fuel types on alumina properties was studied. Citric acid, glycine, and urea were used as fuels along with aluminum nitrate as an oxidizer. The properties of porous alumina produced using three different fuels were compared to determine the optimum fuel that could produce the best properties for implant applications. X-ray diffraction analysis showed that single-phase alumina powder was obtained in all samples. Morphology observation using scanning electron microscope (SEM) on sintered bodies showed open pores which had potential to be used in implant applications. Porous alumina produced using glycine as fuel (AG) showed the best properties; high surface area of 8.7 m²/g, porosity of 70% and sintered density 1.37 g/cm³.     

Effects of SO2/SO2 on the efficiency with which MgO inhibits vanadic corrosion in residual fuel fired gas turbines

The use of MgO as a fuel additive to combat vanadic corrosion is widely accepted practice for boilers and turbines operating on residual or low grade fuels. MgO has the ability to form high melting stable vanadates but the presence of SO₂/SO₂ can react with the magnesium and reduce its effectiveness. This paper aims to quantify the effectiveness of MgO as an inhibitor in the presence of increasing amounts of SO_x. A method of determining permissible levels of SO_x to satisfy predetermined corrosion rates or additive efficiencies is described. Examples of the loss of additive efficiency with volume of SO_x at temperatures of 750 and 850°C are given for both nickel and cobalt base alloys.     

Zirconium-Niobium Alloys for Core Elements of Pressurized Water Reactors

The main characteristics of niobium-bearing zirconium alloys used for fabricating fuel element claddings of pressurized water reactors are considered. It is shown that the high corrosion and radiation resistance of zirconium parts is provided by the chemical composition, structure, and phase composition of the alloys. The Zr – Nb alloys developed in Russia provide reliable operation of fuel elements and fuel rod arrays in active reactors and serve as a basis for new modifications.     

不锈钢双极板电弧离子镀Cr1-xNx薄膜改性研究

用电弧离子镀方法在质子交换膜燃料电池(PEMFC)不锈钢双极板表面沉积一系列Cr_(1-x)N_x(x=0.28—0.50)改性薄膜,对薄膜的成分、相组成以及改性双极板的导电、耐蚀等性能进行了分析测试.结果表明,双极板的导电与耐蚀性能因沉积Cr_(1-x)N_x薄膜而显著提高,并且与薄膜的成分和相组成密切相关:当x值从0.28增加到0.50,薄膜由Cr+Cr_2N转变为Cr_2N,再转变为Cr_2N+CrN,最终变为CrN;当薄膜由单相组成时,双极板既导电又耐蚀、综合性能最好,与原始不锈钢相比,导电性能提高2个数量级以上,而耐蚀性能提高近3个数量级.     

Welding of unique and advanced alloys for space and high-temperature applications: welding and weldability of iridium and platinum alloys†

In the last five decades, significant advances have been made in developing alloys for space power systems for spacecraft that travel long distances to various planets. The spacecraft are powered by radioisotope thermoelectric generators (RTGs). The fuel element in RTGs is plutonia. For safety and containment of the radioactive fuel element, the heat source is encapsulated in iridium or platinum alloys. Ir and Pt alloys are the alloys of choice for encapsulating radioisotope fuel pellets. Ir and Pt alloys were chosen because of their high-temperature properties and compatibility with the oxide fuel element and the graphite impact shells. This review addresses the alloy design and welding and weldability of Ir and Pt alloys for use in RTGs.     

Progress in the pyrochemical processing of spent nuclear fuels

Pyrochemical processes are being developed to recover actinides from spent fuels from light-water reactors and integral fast reactors. The transuranic elements from light-water reactors will be introduced into the integral fast reactor fuel cycle. To meet the requirements of that fuel cycle, transuranic elements are recovered as oxide free metal containing some fission products. This article discusses pyrochemical processes for recovering actinides from light-water reactor and integral fast reactor fuels and for treating the high-level wastes from these processes. The development status of these processes and the plans to demonstrate them using facilities at Experimental Breeder Reactor II are also described.     

Interdiffusion Between Zr Diffusion Barrier and U-Mo Alloy

U-Mo alloys are being developed as low-enrichment uranium fuels under the Reduced Enrichment for Research and Test Reactor (RERTR) program. Significant reactions have been observed between U-Mo fuels and Al or Al alloy matrix. Refractory metal Zr has been proposed as barrier material to reduce the interactions. In order to investigate the compatibility and barrier effects between U-Mo alloy and Zr, solid-to-solid U-10wt.%Mo versus Zr diffusion couples were assembled and annealed at 600, 700, 800, 900, and 1000?°C for various times. The microstructures and concentration profiles due to interdiffusion and reactions were examined via scanning electron microscopy and electron probe microanalysis, respectively. Intermetallic phase Mo₂Zr was found at the interface, and its population increased when annealing temperature decreased. Diffusion paths were also plotted on the U-Mo-Zr ternary phase diagrams with good consistency. The growth rate of interdiffusion zone between U-10wt.%Mo and Zr was also calculated under the assumption of parabolic diffusion and was determined to be about 10³ times lower than the growth rate of diffusional interaction layer found in diffusion couples U-10wt.%Mo versus Al or Al-Si alloy. Other desirable physical properties of Zr as barrier material, such as neutron adsorption rate, melting point, and thermal conductivity, are presented as supplementary information to demonstrate the great potential of Zr as the diffusion barrier for U-Mo fuel systems in RERTR.     

氧、燃气回火防止器与其在气割作业中的应用

氧气、燃气回火防止器是氧-燃气气割、气焊、钢铁连铸等热加工过程中必备的劳动安全防护装置,在氧气和燃气输送管道、气割、气焊中大量使用.重点阐述了气割时干式氧气、燃气回火防止器在不同燃气种类、不同使用要求及不同安装位置的选用方法,指出了实际使用中应注意的问题.     

Interdiffusion Between Potential Diffusion Barrier Mo and U-Mo Metallic Fuel Alloy for RERTR Applications

U-Mo alloys are being developed as low enrichment uranium fuels under the Reduced Enrichment for Research and Test Reactor Program. Previous investigation has shown that the interdiffusion between U and Mo in γ(bcc)-U solid solution is very slow. This investigation explored interdiffusional behavior, especially in regions with high Mo concentration, and the potential application of Mo as a barrier material to reduce the interaction between U-Mo fuel and Al alloys matrix. Solid-to-solid U-10wt.%Mo versus Mo diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 °C for 960, 720, 480, 240, 96 h, respectively. The interdiffusion microstructures and concentration profiles were examined via scanning electron microscopy and electron probe microanalysis, respectively. As the Mo concentration increased from 22 to 32 at.%, the interdiffusion coefficient decreased while the activation energy increased. The growth rate constant of the interdiffusion zone between U-10wt.%Mo versus Mo was also determined and compared to be 10⁴-10⁵ times lower than those of U-10wt.%Mo versus Al and U-10wt.%Mo versus Al-Si systems. Other desirable physical properties of Mo as a barrier material, such as neutron adsorption rate, melting point and thermal conductivity, are also highlighted.     

熔融碳酸盐燃料电池材料的腐蚀与防护

熔融碳酸盐燃料电池(MCFC)是一种通过氢或矿物燃料 的氧化将化学能直接转化成电能的能源转化装置.目前电池一般由含Cr量为2-10%(mass)的多 孔Ni-Cr合金阳极、LiAlO2电解质板及多孔NiO阴极组成.单体电池间通过材质为Fe或Ni基 合 金的金属双极板串联连接.目前MCFC已达MW级水平,但主要电池材料的腐蚀极大地阻碍了其 商业化应用.MCFC中的腐蚀主要表现为2种形式,即NiO阴极的溶解和金属部件如双极板的腐 蚀.目前已有不少有关MCFC材料腐蚀的研究报道,但对其腐蚀机制仍未完全澄清.本文综述这 方面的研究进展,并提出待澄清的若干问题.     

High-density U-Mo fuel for research reactors

The effect of the content of the main alloying element (molybdenum in an amount of from 1.5 to 9 wt.%) and of additives of aluminum, silicon, and tin on the structure, phase composition, and properties of uranium alloys used as dispersion nuclear fuel in research reactors is studied. The heat treatment parameters ensuring a stable structure in the alloys are determined. Segregation of secondary phases in uranium alloys with molybdenum and molybdenum and tin additives is studied. Heat treatment parameters optimum for providing fine segregations of UAl₂ and U₅Sn₄ particles in the matrix are determined. The results of the study are used to develop a composition for fabricating fuel grit and dispersion fuel for reactor tests.     

镁基能源材料研究进展

作为最轻的金属结构材料,Mg合金在轻量化方面已经得到了越来越多的应用。Mg具有较低的电极电位及储氢量较大的特点使得Mg在能源材料方面发挥越来越重要的作用。综述了Mg作为储氢材料和电池材料的研究进展,着重介绍了Mg基储氢材料的性能改善、制备方法等,同时对Mg二次电池和燃料电池体系进行了简要介绍。此外,还较详细地介绍了具有高容量储氢性能的Mg基复杂氢化物的研究现状及结果。     

Electrometallurgically treating metal, oxide, and al alloy spent nuclear fuel types

Electrorefining uranium in a molten salt bath is the key step in the electrometallurgical treatment of spent nuclear fuels. The versatility of the electrometallurgical treatment suggests its use for a variety of spent fuel types, as well as for nonnuclear metal-separation applications.     

点缺陷对MOX燃料热导率的影响研究

MOX燃料作为快堆燃料重要的候选燃料类型之一，是核燃料闭式循环的关键环节。导热性能是MOX燃料在堆内服役的关键参数，将直接影响快堆的安全性。目前通常只对实测数据进行拟合得到其热导率经验公式，缺乏对不同Pu含量和氧金属比（O/M）的MOX燃料热导率的理论分析。本文基于经典声子热传导理论，通过对MOX燃料在不同Pu含量和O/M下热导率影响因素的分析，研究了不同类型点缺陷对其热导率的影响。研究结果表明，采用声子传导模型可以很好地预测不同成分MOX燃料的热导率。MOX燃料中离子替代型点缺陷造成的质量差和半径差对热导率的影响权重相对较小，而MOX燃料不同O/M比造成的氧空位型点缺陷对热导率的影响权重相对较大。本研究对于不同成分MOX燃料的热导率预测和成分设计具有重要意义。     

The application of ultra-thin palladium alloy metal foils in gas-phase hydrogen separation or purification

Palladium and platinum metals or their alloys have been used in fuel cells as membranes for the separation and purification of hydrogen from other gases for more than 50 years. This technology has generated a great deal of interest with the recent growth of the fuel cell industry as an enabling technology in the future commercial application of a proton exchange membrane fuel cell system.     

Effect of ethanol as gasoline additive on vehicle fuel delivery system corrosion

In this research, the effect of ethanol as gasoline additive has been investigated into metal corrosion of a fuel delivery system. Corrosion tests have been performed in gasoline with different percentages of ethanol, using weight loss (immersion test) and electrochemical impedance stereoscopy (EIS) procedures. Surface of test specimens were checked by scanning electron microscopy (SEM) after 144 days of immersion in test solution. Also corroded components were analyzed using energy‐dispersive X‐ray analysis (EDAX) method. Test results, investigations, and analyses, altogether show more corrosion with the increase in ethanol percentage and water content in gasoline. Test results show that among different materials in fuel delivery system, aluminum alloys and hard soldering alloys have less corrosion than the others. Also chloride and sulfide were recognized as the main compound of corrosion products; therefore, the control of these two elements in fuel delivery system is a must in case of using ethanol as fuel additive in near future.