蒙特卡罗方法是求解中子输运问题的重要方法，基于蒙卡方法的计算程序不仅可以作为反应堆分析的工具，而且其结果还可以作为其他相关程序的基准解。随着先进和新概念核能系统的发展，蒙卡方法和程序成为了研究和发展的趋势和重点。 相比于国外，我国还没有系统成熟、应用广泛的蒙卡分析程序。由于国外核能监管部门的限制，我们无法获取关键的新版本的蒙卡程序，这限制了科研发展和国际交流；而且现有的方法和程序针对性不强，就反应堆分析而言不能满足需求。因此，本课题开展了堆用自主蒙卡程序研发及反应堆蒙卡模拟相关的关键基础方法及算法研究等工作。 课题研发了自主堆用蒙卡程序RMC的主体构架，实现了其临界计算、通量统计功等能，提出了新的能量查找与截面调用、输运过程计算等方法。经过临界基准题、组件计算问题以及简单全堆问题的计算验证，说明了RMC程序在保证计算精度的前提下，与现有蒙卡程序相比提高了计算效率。RMC程序的研发，实现了国内堆用蒙卡程序的突破。 结合连续变化介质蒙卡模拟的实际需求，本课题提出并研究了IDeltatracking方法以及KDE连续通量统计方法，实现了连续变化介质问题高效及准确的计算分析。研究提出的方法，为973课题“超临界水堆特定条件下堆芯物理特性及其分析方法的基础研究”提供了新的思路和方法，实现了超临界水堆的精确计算分析。 适应全堆计算的需求，课题提出了全新的蒙卡全堆计算方法响应矩阵蒙卡方法及基于此的RMMC+MC方法，通过响应概率代替碰撞概率进行抽样，对传统蒙卡模拟思路进行了改进。在保证计算精度的前提下，有效减小了计算时间和方差，实现了计算效率十几倍到几十倍的提升。 通过本课题的研究，实现了反应堆蒙卡计算方法上的创新以及程序研发上的突破。在反应堆蒙卡计算中的一些关键问题上，如输运过程模拟、能量查找与截面调用、连续变化介质模拟、全堆计算等，均提出了新的计算方法或思路；自主研发并检验了堆用蒙卡程序RMC，为进一步的方法研究、功能增加、程序推广交流等奠定了基础。
Monte Carlo method is a very important method of solving neutron transport problems,the calculation codes based on Monte Carlo method can be used as reactor analysis tools, and also the results od Monte Carlo codes are often used as benchmark results for other reactor analysis codes. With the development of advanced and new concept reactor systems, Monte Carlo method and codes have steadily became the focal points to be studied and developed in the world. Compared with the developments abroad, we haven’t had a systematical, mature and widely used self-developed Monte Carlo anaylsis code. As most of the key Monte Carlo codes are controlled by foreign regulatory departments, we can’t get them or can only get the outdated versions of the codes, which may cause a lot of restrictions on research and international communications. Also with our research, we find the existing Monte Carlo method and codes are not specially developed, sometimes they can’t meet the requirements in reactor physics analysis. Due to these reasons, this thesis focuses on the development of independent reactor Monte Carlo code and research on key and fundamental algorithms and methods in reactor Monte Carlo simulation. The main program of independent reactor Monte Carlo code RMC is developed, which can treat 3-D problems with complex geometries and continuous-energy crosssectionsand take out criticality calculation and flux tally, with new energy search and cross-section invoke method and neutron transport method. By using criticality benchmarkproblems, assembly problems and simple full core problems, RMC is tested and validated. Compared with the existing Monte Carlo code - MCNP, the performances of RMC on calculation time and eciency are improved. The development of RMC achieves a big breakthrough in Chinese reactor Monte Carlo codes. To meet the actual needs of continuously varying materials Monte Carlo simulation, a new method named IDelta-tracking method and a new KDE continuous flux tally method have been put out in the thesis. The IDelta-tracking method and KDE method can calculate problems with continuously varying materials accurately and e efficiently. The methods proposed in this thesis are used in 973 program ”the fundamental research on SCWR reactor physics characters and analysis methods in certain situations” as a new simulation method and can provide accurate simulations for SCWR. In full core Monte Carlo simulation research, new Response Matrix Monte Carlo method and hybrid RMMC+MC method are proposed and discussed in the thesis. By using response probabilities instead of collision probabilities, the new methods make improvements to the conventional Monte Carlo method. On the premise of precision guarantee, the new Response Matrix Monte Carlo method and RMMC+MC method can efficiently reduce the calculation time and variance of results, and get more than ten times to dozens of times increase in calculation FOM. The thesis’s research work acheives innovation in Monte Carlo reactor analysis method and break
