中文摘要：

加速器驱动的次临界系统（ADS）由于外中子源的存在导致堆芯中子通量密度分布强烈的各向异性，须采用中子输运方法进行计算。采用蒙特卡罗输运耦合燃耗方法进行设计计算效率很低，而传统反应堆两步法中堆芯计算采用中子扩散方法，对ADS并不适用。为此，开发了两步法堆芯确定论输运的次临界系统中子学分析程序，第1步组件计算采用超细群共振组件程序，产生堆芯计算所需的少群均匀化参数；第2步堆芯计算采用三维三角形离散坐标节块输运程序DNTR进行中子学计算，堆芯燃耗采用微观燃耗的方法进行计算。通过对多栅元燃耗、BN600基准题以及ADS均匀装料模型计算检验，表明该程序具有良好的计算精度和计算效率。

英文摘要：

The neutron flux density distribution of the accelerator driven subcritical system （ADS） is strongly anisotropic because of the external neutron source and thus neutron transport calculation is necessary. The Monte Carlo transport coupled with burnup calculation method is not efficient enough to be applied to the design work of ADS, and the traditional two-step reactor analysis method with the neutron diffusion method is not suitable. Therefore, the two-step ADS analysis code with the deterministic transport method was developed. The first step was carried out by the lattice code with the hyper-fine group resonance calculation method to provide the few- group homogenized parameters for the core calculation. The second step was executed by the three-dimensional discrete ordinates nodal transport calculation code （DNTR） in triangular meshes. The micro-depletion method was used for the burnup calculation of the core. The code was validated by a multi-cell burnup problem, the BN600 benchmark and the uniformly fuelled ADS model. The numerical results indicate that the code FMADS is reliable and efficient.