基于蒙特卡罗方法的引入中子阱结构板式燃料研究堆堆芯物理分析

Core Physics Analysis of Plate-fuel Research Reactor Introducing Neutron Trap Structure Based on MC Method

对于研究堆,在堆芯功率不变的情况下,通过引入中子阱结构可大幅提高阱内热中子注量率峰值,同时这一结构的引入势必会对堆芯产生很大的影响,故需深入全面分析。本文参考国际上著名的研究堆,建立新型带有中子阱结构的研究堆物理分析模型,使用自主开发的堆用蒙特卡罗程序RMC探讨Be阱内热中子注量率峰值随阱外径的变化关系,并在该最佳Be阱尺寸下,比较无阱(Al)结构与Be阱结构堆芯热中子注量率峰值以及功率峰值因子。在堆芯热功率不变的条件下,Be阱结构内的热中子注量率峰值是无阱堆芯的2.6倍,而相应的功率峰值因子只提高了11%,这充分说明了引入中子阱结构是提高研究堆热中子注量率峰值的一种经济有效的方法。

For the research reactor, introducing a neutron trap structure into the core can greatly improve the thermal neutron fluence rate peak under the condition of the core thermal power remaining the same. While the neutron trap structure introduced will have great influence on the core, it requires an in-depth analysis. Referring to the famous research reactors in the world, a new research reactor physics analysis model with a neutron trap structure was established in the paper. The relationship between the thermal neutron fluence rate peak in the neutron trap and the diameter of the Be trap was explored with the RMC code developed by our REAL Team. In the preferred size of the Be neutron trap, the thermal neutron fluence rate peak and power peak factor between the A1 trap and the Be trap introduced in the established physical model were compared. The results show that the thermal neutron fluence rate peak in the research reactor with the Be neutron trap is 2.6 times in the research reactor with no neutron trap. At the same time, the power peak factor increases only 11%. This fully shows that introducing a neutron trap structure is an economical and effective way to improve the thermal neutron fluence rate peak in research reactors.