【作者】 陈晓彤； 张伟； 朱洪伟； 高泽林； 王桃葳； 徐刚； 贺林峰； 祁美丽； 李彩霞； 葛之萌； 李林艳； 徐建军； 刘兵； 唐亚平；

【Author】 CHEN Xiao-tong;ZHANG Wei;ZHU Hong-wei;GAO Ze-lin;WANG Tao-wei;XU Gang;HE Lin-feng;QI Mei-li;LI Cai-xia;GE Zhi-meng;LI Lin-yan;XU Jian-jun;LIU Bing;TANG Ya-ping;Institute of Nuclear and New Energy Technology,Tsinghua University;

【机构】 清华大学核能与新能源技术研究院；

【摘要】 高温气冷堆以弥散在球形基体石墨中的包覆颗粒为燃料元件,其能量密度低、固有安全性好,同时也大大增加了乏燃料的数量和体积。随着我国高温气冷堆商业化进程发展,亟须建立相应的乏燃料后处理技术。球形乏燃料基体石墨与包覆燃料颗粒的分离,是乏燃料后处理至关重要的一步。高温氧化法能够利用一次流程分离石墨基体与包覆颗粒,处理效率高,减容效应好,但裂变金属会伴随基体石墨氧化而释放,其过程耦合了多个物理和化学反应,与基体石墨的氧化过程密切相关,对尾气处置和环境评估意义重大,需要开展系统的研究。本课题基于HTR-10辐照后基体石墨球氧化的源项分析结果,以长寿命裂变金属Sr-90为研究对象,研究了裂变金属在基体石墨氧化中的释放热力学行为与动力学规律,阐明了裂变金属对基体石墨氧化过程的影响,得到了基体石墨氧化中裂变金属Sr的释放机制。研究成果将为球形乏燃料高温氧化处置提供基础研究支持,同时为放射性核用石墨处置提供新的思路和依据。更多还原

【Abstract】 High Temperature Gas-cooled Reactor(HTGR) uses spherical fuel elements with TRISO coated fuel particles uniformly dispersed in graphite matrix,which efficiently decreases the energy density and prominently enhances the inherent safety property.However,the amount and volume of spent fuels is also greatly increased due to the structure property.As the continuous advancement of the industrialization process of HTGR in China,it is urgent to reprocess spherical spent fuel elements.High temperature oxidation method is an alternative route of HTGR spent fuels’ reprocessing,as it is of high efficiency for treatment,great reduction in volume and easy process for industrialization.The study on fission production release is vital for predicting its migration behavior and understanding the decontamination of radioactive exhaust gas.In this study,the release regime of a typical metallic fission product,Sr-90 was studied during high temperature oxidation of matrix graphite based on our previous study on radioactive source terms of HTR-10 spent fuel.We investigated the thermodynamics and kinetics procedures of releasing metallic fission products during graphite matrix oxidation,as well as the effect of introduction of metallic fission products on graphite matrix oxidation,with the aim to elucidate the synergistic mechanism of graphite matrix oxidation and metallic fission products releasing.This study provided a foundation for the establishment of technical routes for high temperature oxidation reprocessing of spherical spent fuel elements of high-temperature gas-cooled reactors,as well as the disposal method for radioactive nuclear graphite.更多还原