运行工况下固态堆芯基体的高温力学响应

The high-temperature mechanical response of solid-state core monolith under operating condition

热管冷却反应堆是核反应堆电池的首选堆芯之一,热管堆固态堆芯高温膨胀的力学性能需要引起重视。为了获得热管冷却反应堆316H不锈钢基体在高温下的力学变化,以MegaPower作为分析对象,采用开源蒙特卡罗程序(OpenMC)和商用有限元计算软件ANSYS Mechanical,对反应堆满功率运行工况进行了热力耦合分析。结果表明:1)在满功率运行水平,堆芯基体会产生显著的温度集中和热应力集中,燃料和基体的峰值温度分别为1 023 K和970 K,基体的最大热应力为49.5 MPa;2)在高温蠕变的效应下,基体的应力会显著降低,应力分布趋于均匀;3)在堆芯运行过程中,基体等效总应变只有微小变化,而等效弹性应变的减少和等效蠕变应变的增加几乎是同步且等量进行的。

The mechanical properties of heat pipe-cooled reactor which is a preferred core for nuclear reactor batteries at high temperatures needs attention.Taking MegaPower as the object,a thermal-mechanical coupling calculation of the reactor under full power operation condition is carried out using the open source Monte Carlo program(OpenMC)and ANSYS mechanical.The results show:(1)The core monolith generates significant temperature and thermal stress concentration,with peak temperatures of 1023 K for the fuel and 970 K for the monolith,and the highest thermal stress of 49.5 MPa for the monolith;(2)Because of the effect of high-temperature creep,the stress in the monolith decreases significantly,and the stress distribution tends to be uniform.(3)During the core operation,the total equivalent strain of the monolith changes slightly,while the reduction of the equivalent elastic strain and the increase of the equivalent creep strain is almost simultaneous and equal.