摘要
包覆颗粒弥散燃料是耐事故燃料研究的热点。采用放电等离子烧结制备包覆颗粒弥散燃料芯块,研究了烧结工艺对芯块性能的影响,并对芯块进行了物相检测、金相检测以及微观结构表征分析。研究发现,包覆颗粒弥散燃料芯块放电等离子烧结的最佳工艺为助烧剂添加量7%,在1850℃、45 MPa下保温15 min,芯块相对密度可达98.5%;烧结后芯块为纯β相,表明SPS快速烧结能够较好地控制物相转变;在最佳工艺条件下获得的芯块中未观察到芯块中TRISO颗粒出现明显接触的现象,TRISO颗粒整体完整性较好;热冲击试验中,芯块在一次热冲击后表面未出现贯穿的微裂纹,保持较好的完整性。综上,放电等离子烧结工艺可用于快速制备致密度高、无物相转变且抗热冲击性能良好的包覆颗粒弥散燃料芯块。
Accident tolerant fuel can improve the safety of nuclear reactor core and strengthen the ability of nuclear reactor to withstand serious accidents.Coated particle dispersed fuel has become a hot research topic in accident tolerant fuel in recent years,due to its high thermal conductivity and good radiation resistance stability.Coated particle dispersed fuel consists of three-dimensional isotropic coated particles as the fuel phase and silicon carbide as the matrix phase,adopting the fuel form of coated particle dispersed in the silicon carbide matrix.However,due to the low self-diffusion rate of SiC,it is difficult to achieve high densification by solid phase sintering,which is only controlled by diffusion.The existing sintering process mainly involves adding sintering aids or generating liquid glass phase to assist in the sintering of SiC powder.Spark plasma sintering(SPS)process can activate powder particles and promote sintering,and has been widely used in nuclear ceramic sintering in recent years.This article used SPS to prepare coated particle dispersed fuel pellets,and studied the influence of sintering process parameters on the density of the coated particle dispersed fuel pellets,such as the amount of sintering additive addition,maximum sintering temperature,maximum sintering pressure,and holding time.It is found that the best process parameters for SPS sintering of coated particle dispersed fuel pellet is 7% of sintering additive addition,holding 15 minutes at 1850℃ and 45 MPa.Under such process parameter,the relative density of pellet can reach 98.5% of theoretical density.In addition,the sintering mechanism of coated particle dispersed fuel was studied and it is found that the sintering of coated particle dispersed fuel can be divided into five stages.Phase detection,metallographic detection and microstructure characterization analysis of the coated particle dispersed fuel pellets were carried out.The XRD examination results indicate that after sintering,the coated particle dispersed fuel pellet is pure β phase,which indicate that SPS rapid sintering can better control the phase transition.The metallographic examination results indicate that there is no obvious contact between TRISO particles in the coated particle dispersed fuel pellet obtained under the optimal process conditions.The SEM examination results show that the overall integrity of TRISO particles is good,indicating that the structure of TRISO particles dose not break during the sintering process.In the thermal shock test,there are no penetrating micro-cracks on the surface of the fuel pellet after a thermal shock,which maintain good integrity.
作者
刘伟
邵宗义
刘文涛
孟莹
冯帅帅
蔡振方
LIU Wei;SHAO Zongyi;LIU Wentao;MENG Ying;FENG Shuaishuai;CAI Zhenfang(CNNC Key Laboratory of Fabrication Technology of Reactor Irradiation Special Elements,Baotou 014035,China;China North Nuclear Fuel Co.,Ltd.,Baotou 014035,China)
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2023年第9期1810-1816,共7页
Atomic Energy Science and Technology
关键词
耐事故燃料
包覆颗粒弥散燃料
放电等离子烧结
accident tolerant fuel
coated particle dispersed fuel
spark plasma sintering
