A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-lo...A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-loop treatment of spent fuel and the nuclear chemical industry.In this study,1 wt.%,3 wt.%,5 wt.%,7 wt.%,and 9 wt.%Zr-Gd alloys were designed and fabricated with Zr-702 as the control element.The electrochemical behavior of the Zr-Gd alloys in boiling concentrated HNO3 was investigated,and the neutron shielding effect on plate thickness and Gd content was simulated.The experimental results demonstrate that the corrosion resistance of the alloy decreased slightly before~7-9 wt.%with increasing Gd content;this is the inflection point of its corrosion resistance.The alloy uniformly dissolved the Gd content that could not be dissolved in the Zr lattice,resulting in numerous micropores on the passivation coating,which deteriorated and accelerated the corrosion rate.The MCNP simulation demonstrated that when the Gd content was increased to 5 wt.%,a 2-mm-thick plate can shield 99.9%neutrons;an alloy with a Gd content≥7 wt.%required only a 1-mm-thick plate,thereby showing that the addition of Gd provides an excellent neutron poisoning effect.Thus,the corrosion resistance and neutron shielding performance of the Zr-Gd alloy can meet the harsh service requirements of the nuclear industry.展开更多
在室温条件下,以不同浓度的HNO3溶液(质量分数分别为10,20,30 and 40%)为氧化介质处理沥青球,而后直接进行高温炭化处理,利用FT-IR、XPS、SEM和元素分析表征HNO3氧化沥青球及其炭化样的化学结构和表面形貌。结果表明:用30%HNO3氧化12h...在室温条件下,以不同浓度的HNO3溶液(质量分数分别为10,20,30 and 40%)为氧化介质处理沥青球,而后直接进行高温炭化处理,利用FT-IR、XPS、SEM和元素分析表征HNO3氧化沥青球及其炭化样的化学结构和表面形貌。结果表明:用30%HNO3氧化12h的沥青球在900℃高温炭化后能够保持良好的球形度和表面形貌;HNO3处理引入的-NO2官能团在400℃前转化为胺基,促进了沥青分子的交联,保证了沥青球炭化过程的顺利进行;当炭化温度为900℃时,胺基进一步发生了环化和芳构化反应,氮原子以吡啶氮和季氮形式存在。展开更多
基金supported by the National Natural Science Foundation of China (Nos.52201021 and 52101099)Key Research and Development Program of Shaanxi (2021GY-249,2021GY-233)+1 种基金Natural Science Basic Research Program of Shaanxi (No.2020JC-50)Shaanxi Provincial Natural Science Youth Foundation (2022JQ-410).
文摘A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-loop treatment of spent fuel and the nuclear chemical industry.In this study,1 wt.%,3 wt.%,5 wt.%,7 wt.%,and 9 wt.%Zr-Gd alloys were designed and fabricated with Zr-702 as the control element.The electrochemical behavior of the Zr-Gd alloys in boiling concentrated HNO3 was investigated,and the neutron shielding effect on plate thickness and Gd content was simulated.The experimental results demonstrate that the corrosion resistance of the alloy decreased slightly before~7-9 wt.%with increasing Gd content;this is the inflection point of its corrosion resistance.The alloy uniformly dissolved the Gd content that could not be dissolved in the Zr lattice,resulting in numerous micropores on the passivation coating,which deteriorated and accelerated the corrosion rate.The MCNP simulation demonstrated that when the Gd content was increased to 5 wt.%,a 2-mm-thick plate can shield 99.9%neutrons;an alloy with a Gd content≥7 wt.%required only a 1-mm-thick plate,thereby showing that the addition of Gd provides an excellent neutron poisoning effect.Thus,the corrosion resistance and neutron shielding performance of the Zr-Gd alloy can meet the harsh service requirements of the nuclear industry.
基金Nature Science Foundation of China (50672025)Science and Technology Commission of Shanghai Municipality (065258033,06DZ22003)~~
文摘在室温条件下,以不同浓度的HNO3溶液(质量分数分别为10,20,30 and 40%)为氧化介质处理沥青球,而后直接进行高温炭化处理,利用FT-IR、XPS、SEM和元素分析表征HNO3氧化沥青球及其炭化样的化学结构和表面形貌。结果表明:用30%HNO3氧化12h的沥青球在900℃高温炭化后能够保持良好的球形度和表面形貌;HNO3处理引入的-NO2官能团在400℃前转化为胺基,促进了沥青分子的交联,保证了沥青球炭化过程的顺利进行;当炭化温度为900℃时,胺基进一步发生了环化和芳构化反应,氮原子以吡啶氮和季氮形式存在。
