大型先进压水堆堆芯机械补偿控制模式

研究了AP1000堆芯物理计算程序的计算方法，分析了该程序尤其是机械补偿（MSHIM）控制模式计算功能的理论模型、计算方法及应用范围，对比了大型先进压水堆堆芯设计与AP1000的差异，评估了AP1000反应堆MSHIM计算功能在大型先进压水反应堆堆芯MSHIM计算功能的适用性。基于大型先进压水堆堆芯物理建模，针对大型先进压水反应堆首循环及平衡循环的典型燃耗点进行典型的100%-70%-100%和100%-50%-100%负荷跟踪运行模式计算分析，并依据计算结果对大型先进压水堆的MSHIM运行模式进行了分析。针对大型先进压水反应堆首循环及平衡循环，开展机械补偿控制初始启动运行、再启动运行计算分析，研究机械补偿控制模式的堆芯初始启动和再启动运行能力。计算结果表明:采用MSHIM运行模式的大型先进压水堆，不调节硼浓度的情况下，在首循环、平衡循环典型燃耗下具有一定的负荷跟踪能力；启动、再启动运行模式则需要配合调节硼浓度才能完成。

Mechanical shim mode analysis for large-scale advanced pressurized water reactor

The mechanical shim (MSHIM) operation mode and the load following technology of the large-scale passive advanced PWR core use the relevant design of the AP1000 nuclear power plant as reference, but differ from it due to its higher power and unique control rod loading pattern. Therefore, it is extremely necessary to analyze the applicability of evaluation code for the MSHIM operation mode, the performance of the MSHIM load following operation mode, the characteristics of the start-up and restart processes based on the design of large-scale passive advanced PWR. In this paper, the applicability of MSHIM operation mode for the AP1000 calculation code to the large-scale passive advanced PWR is firstly evaluated based on the analysis of the methodology for the PWRs MSHIM operation mode and the analysis of the difference between AP1000 and the large-scale passive advanced PWR. Secondly, the typical 100%-70%-100% and 100%-70%-100% load following operation modes of both the initial and the equilibrium cycles are calculated and analyzed based on the neutronics modeling of the large-scale passive advanced PWR core. In addition, the operation capability of the initial start-up and restart processes in MSHIM mode of the initial and equilibrium cycles are simulated and analyzed quantitatively. The numerical results show that MSHIM mode has the certain ability for load following in both initial and equilibrium cycles without adjusting the boron concentration, but for start and restart conditions it is required to adjust the concentration of boron.