摘要
Abstract
After the Fukushima accident in Japan,further improving the accident tolerance capability has become the key research direction of nuclear fuel cladding materials.SiC composites have significant advantages in high temperature strength,irradiation stability,creep resistance,oxidation resistance,wear resistance,etc.,and have great accident tolerance potential under light water reactor accident conditions.Therefore,the nuclear fuel solution based on SiC composites is a research hotspot in the international nuclear fuel community.Different from zirconium alloy,SiC will produce irradiation defects under the action of neutron field,which will lead to a significant decrease in thermal conductivity and further affect the radial temperature gradient of fuel rods;In addition,radiation swelling will occur,and the amount of radiation swelling is related to the temperature gradient.In this paper,the self-developed SiC fuel performance analysis program is used to analyze the service behavior of SiC clad fuel system under operation and shutdown conditions.The results show that under normal operating conditions,the decrease of thermal conductivity caused by irradiation damage and closing time of pellet cladding gap,and then increase the fuel operating temperature;Under the hot shutdown condition,compared with the normal operation condition,the hoop tensile stress inside the cladding will increase.Under the cold shutdown condition,the pressure difference inside and outside the cladding increases due to the decrease of the system pressure,and the hoop tensile stress inside the cladding will further increase when the radiation swelling gradient is superimposed.In addition,when the total wall thickness of the cladding remains unchanged,the increase of the thickness of the inner fiber composite layer helps to reduce the peak hoop tensile stress of the monolithic layer,thus reducing the risk of cladding failure.关键词
SiC/停堆/包壳/性能Key words
SiC/shutdown/cladding/performance分类
能源科技
