Models to describe the damage and fracture behaviors of the interface between the fuel foil and cladding in UMo/Zr monolithic fuel plates were established and numerically implemented.The effects of the interfacial coh...Models to describe the damage and fracture behaviors of the interface between the fuel foil and cladding in UMo/Zr monolithic fuel plates were established and numerically implemented.The effects of the interfacial cohesive strength and cohesive energy on the irradiationinduced thermal-mechanical behaviors of fuel plates were investigated.The results indicated that for heterogeneously irradiated fuel plates:(1)interfacial damage and failure were predicted to be initiated near the fuel foil corner with higher fission densities,accompanied by the formation of a large gap after interface failure,which was consistent with some experimental observations;high tensile stresses in the fuel foil occurred near the edges of the failed interface,attributed to through-thickness cracking of the fuel foil,as found in some post-irradiation examinations;(2)the cohesive strength and cohesive energy of the interface both influenced the in-pile evolution behaviors of fuel plates;a lower cohesive strength or cohesive energy resulted in faster interfacial damage;(3)after interface fracture,the thickness of the whole plate increased to a greater degree(by~20%)than that of the samples without interfacial damage,which was attributed to the locally enhanced Mises stresses and the nearby creep deformations around the cracked interface.This study provided a theoretical basis for assessing failure in fuel elements.展开更多
Generally, the atomization of UMo particles is done under vacuum or argon atmosphere, and the surface modification of these UMo particles is, usually, carried on through a further process. The techniques for surface m...Generally, the atomization of UMo particles is done under vacuum or argon atmosphere, and the surface modification of these UMo particles is, usually, carried on through a further process. The techniques for surface modification of atomized UMo particles, aimed to control the Fuel/Matrix interaction, involve, in some cases, complex methodologies and often with minor effect due to the limited solubility of third elements in solid UMo alloy. The atomization and surface conditioning, applied in separate stages, may affect the efficiency of powder production process. Then, the main goal of this study is to explore the surface modification of UMo particles in liquid state or during the solidification that follows the centrifugal atomization process. Through the change of atomization atmosphere, could be possible to promote liquid/gas reactions, with a higher solubility of the modifier element in micro drops of UMo alloy, before they become solid particles. This paper presents comparative results of centrifugal atomization of UMo particles, carried out under inert argon and reactive nitrogen atmospheres. Dissolved nitrogen contents, measured by SEM-EDS analyses, reached up to 7.57 wt% at the center of under nitrogen atomized particles, very higher than 0.84 wt% of nitrogen measured at the center of UMo particle atomized under argon. The presence of uranium nitride was partially verified by conventional XRD analysis. Nevertheless, Out-of-Pile interaction test result, reveals decreasing of aluminium contents into UMo particles atomized under nitrogen atmosphere;Just 3.77 wt% of Al was the maximum content detected in the center of these particles, very lower than 29.11 wt% of Al measured inside UMo particles atomized under argon. Finally, it is possible to conclude that the atomization under reactive atmosphere may modify the surface composition and the behavior of UMo fuel particles dispersed in aluminium, for dispersion type nuclear fuel application.展开更多
Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel ...Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047). These techniques were used to improve the metallurgical bonding between the UMo and the cladding by rolling. Finally, design parameters and manufacture of UMo plate fuels were established. Mechanical tests were used to characterize the plates, resulting in UTS values of about 700 and 1000 MPa for the UMo alloys. These results are complemented with metrological analyses, X-Ray diffraction (XRD), thermal analyses, and metallography. X-rays and ultrasound scanners were used to monitor bonding and the co-rolling effects. These initial results show the main obstacles to the engineering development of UMo monolithic plate fuels with Al-6061 cladding, and these are discussed herein.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12132005,11772095,12102094)the Foundation from Science and Technology on Reactor System Design Technology Laboratory。
文摘Models to describe the damage and fracture behaviors of the interface between the fuel foil and cladding in UMo/Zr monolithic fuel plates were established and numerically implemented.The effects of the interfacial cohesive strength and cohesive energy on the irradiationinduced thermal-mechanical behaviors of fuel plates were investigated.The results indicated that for heterogeneously irradiated fuel plates:(1)interfacial damage and failure were predicted to be initiated near the fuel foil corner with higher fission densities,accompanied by the formation of a large gap after interface failure,which was consistent with some experimental observations;high tensile stresses in the fuel foil occurred near the edges of the failed interface,attributed to through-thickness cracking of the fuel foil,as found in some post-irradiation examinations;(2)the cohesive strength and cohesive energy of the interface both influenced the in-pile evolution behaviors of fuel plates;a lower cohesive strength or cohesive energy resulted in faster interfacial damage;(3)after interface fracture,the thickness of the whole plate increased to a greater degree(by~20%)than that of the samples without interfacial damage,which was attributed to the locally enhanced Mises stresses and the nearby creep deformations around the cracked interface.This study provided a theoretical basis for assessing failure in fuel elements.
文摘Generally, the atomization of UMo particles is done under vacuum or argon atmosphere, and the surface modification of these UMo particles is, usually, carried on through a further process. The techniques for surface modification of atomized UMo particles, aimed to control the Fuel/Matrix interaction, involve, in some cases, complex methodologies and often with minor effect due to the limited solubility of third elements in solid UMo alloy. The atomization and surface conditioning, applied in separate stages, may affect the efficiency of powder production process. Then, the main goal of this study is to explore the surface modification of UMo particles in liquid state or during the solidification that follows the centrifugal atomization process. Through the change of atomization atmosphere, could be possible to promote liquid/gas reactions, with a higher solubility of the modifier element in micro drops of UMo alloy, before they become solid particles. This paper presents comparative results of centrifugal atomization of UMo particles, carried out under inert argon and reactive nitrogen atmospheres. Dissolved nitrogen contents, measured by SEM-EDS analyses, reached up to 7.57 wt% at the center of under nitrogen atomized particles, very higher than 0.84 wt% of nitrogen measured at the center of UMo particle atomized under argon. The presence of uranium nitride was partially verified by conventional XRD analysis. Nevertheless, Out-of-Pile interaction test result, reveals decreasing of aluminium contents into UMo particles atomized under nitrogen atmosphere;Just 3.77 wt% of Al was the maximum content detected in the center of these particles, very lower than 29.11 wt% of Al measured inside UMo particles atomized under argon. Finally, it is possible to conclude that the atomization under reactive atmosphere may modify the surface composition and the behavior of UMo fuel particles dispersed in aluminium, for dispersion type nuclear fuel application.
文摘Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047). These techniques were used to improve the metallurgical bonding between the UMo and the cladding by rolling. Finally, design parameters and manufacture of UMo plate fuels were established. Mechanical tests were used to characterize the plates, resulting in UTS values of about 700 and 1000 MPa for the UMo alloys. These results are complemented with metrological analyses, X-Ray diffraction (XRD), thermal analyses, and metallography. X-rays and ultrasound scanners were used to monitor bonding and the co-rolling effects. These initial results show the main obstacles to the engineering development of UMo monolithic plate fuels with Al-6061 cladding, and these are discussed herein.
