自然循环反应堆流量分配优化研究

由于自然循环反应堆一回路产生的驱动力有限，回路循环总流量较小，因此堆芯流量分配设计与优化非常重要。合理的堆芯流量分配不仅能满足热工安全要求，还能直接提高堆芯的性能。基于以上原因，本文对自然循环反应堆流量分配优化问题进行了初步研究，对闭式并联通道，采用一维流动传热模型，建立了入口阻力系数优化初值求解模型并设计了精确解搜索算法，并耦合堆芯热工分析程序COBRA编写了相应的堆芯流量分配优化程序。选择一自然循环反应堆算例，采用该程序对堆芯寿期内的流量分配优化进行了计算和分析。结果表明，将各典型寿期节点流量分配优化得到的入口阻力优化设置方案取平均值，可获得相对整个循环寿期达到较好优化效果的入口阻力设置方案。针对取平均值这种人工设计方法难以获得全局最优解的缺点，参考现代优化计算方法，提出了一种自动实现循环寿期内流量分配最优化的方法。

Development of Flow Distribution Optimization Program for Natural Circulation Reactor

The driving force of primary loop of natural circulation reactor is limited and the total flow of loop is small, so the design and optimization of core flow distribution are very important. Reasonable core flow distribution can not only meet the thermal safety requirements, but also directly improve the core performance. Based on the above reasons, the optimization of flow distribution in natural circulation reactor was studied preliminarily. A one dimensional flow and heat transfer model was used to establish the initial solution model of inlet resistance coefficient optimization, and an exact solution searching algorithm was designed for the closed parallel channel studied in this paper. Coupled with COBRA, a core thermal analysis program was developed to optimize core flow distribution. By using the program, a natural circulation reactor was chosen as an example to calculate and analyze the flow distribution optimization in the life of the reactor core. The results show that, by taking the average value of the optimal setting scheme of the inlet resistance obtained by the optimization of the flow distribution of a single node in each typical life cycle, a better setting scheme of the inlet resistance in the core cycle life can be obtained. Aiming at the disadvantage that it is difficult to obtain the global optimal solution by means of the artificial design method of average value, a method of automatically realizing the optimization of flow distribution in the cycle life was proposed by referring to the modern optimization calculation method.