中国铅基研究实验堆燃料元件活性区温度场计算分析

Temperature Field Calculation and Analysis on Active Zone of Fuel Element for CLEAR-Ⅰ

中国铅基研究实验堆(CLEAR-Ⅰ)被确定为中国科学院加速器驱动次临界系统(ADS)专项的主选堆型。燃料元件是铅基反应堆的核心部件之一,因此需确保燃料元件的芯块中心温度和包壳最高温度符合设计准则的要求。本文利用有限元程序ANSYS对燃料元件活性区在正常运行工况和失流事故下的温度场进行了数值模拟与分析。正常运行工况下的模拟结果表明,芯块中心温度远低于UO2的熔化温度限值,包壳最高温度低于材料的使用温度限值,满足设计准则中关于上限使用温度的要求。失流事故下的模拟结果表明,失流事故发生后,芯块中心温度和包壳最高温度都会明显上升。当冷却剂流速降低到0.1m/s时,包壳最高温度将超过正常使用温度;紧急停堆滞后时间超过17.5s时,包壳的最高温度将超过事故温度限值。以上分析结果可作为燃料元件安全评审工作的基础。

China LEAd-based Research Reactor （CLEAR- I ） is proposed as the primary choice for Chinese Academy of Sciences （CAS） accelerator driven subcritical system （ADS） project. Fuel element is one of the key components in lead-based reactors. It is necessary to ensure the fuel pellet＇s central temperature and cladding＇s maximum temperature meet the requirements of the design criterion. The finite element code ANSYS was used to simulate the temperature field of active zone in normal operation and loss-of-flow accidents. The simulation results in normal operation show that the fuel pellet＇s central temperature is much lower than the melting point and the cladding＇s maximum temperature is below the operating temperature limit. The simulation results in loss-of- flow accidents show that the fuel pellet＇s central temperature and the cladding＇s maximum temperature significantly increase after the accidents. If the flow rate of coolant is 0.1 m/s, the cladding＇s maximum temperature is higher than the operating temperature limit. If the scram delay time is more than 17.5 s, the cladding＇s maximum temperature is higher than the accident conditions temperature limit. The above simulation and anal- ysis results are to be the basis of safety review work.