从结构热传导角度分析CEFR内钠温度变化速率限值的合理性

Rationality Analysis of CEFR Sodium Temperature Change Velocity Limit from Structure Heat Transfer

CEFR提升功率时要求钠温度变化速率不超过30℃/h,为从理论上论证限值30℃/h的合理性,通过理论分析和ANSYS软件数值模拟两种方式,研究了介质温度变化条件下平板的非稳态热传导响应过程及平板温度进入稳定状态所需的时间。结果表明,换热条件直接影响结构温度达到稳定状态所需的时间,换热条件好时结构和介质温变基本同步,换热条件差时30℃/h的堆内介质温度变化速率能保证介质温度稳定时结构温度达到温变总幅度的60%以上。30℃/h钠介质温度变化速率基本使换热条件差的条件下结构温度场进入稳定状态的速率与堆内钠介质温度变化相对同步,降低了温度变化带来的热应力分布和变化的复杂性,基本保证了结构实际温度与稳态设计温度的一致性。

It is required that the sodium temperature change velocity shall not exceed30 ℃/h when elevating CEFR power.Both the theoretical analysis and ANSYS numerical simulation were used to investigate the transient heat transfer process of a plate under the condition of external sodium temperature change and the time needed for the plate temperature to reach a steady state,so as to demonstrate the rationality of the limit 30 ℃/h.The result shows that the convective heat transfer condition directly affects the time needed for the structure temperature to enter a steady state.The temperature change of structure follows closely that of sodium in the condition of good convection heat transfer.In the condition of poor convection heat transfer,the sodium temperature change velocity of 30 ℃/h can ensure that the structure temperature could reach more than 60% of the total temperature change amplitude when sodium temperature becomes steady.The 30℃/h basically ensures that the temperature change velocityof the structure being into steady state is the same to that of sodium,which can reduce the complexity for distribution and change of thermal stress and guarantee the uniformity of the actual temperature and the steady-state design temperature of structure.