This paper presents the three new pin-resolved transient solvers of PROTEUS-MOC developed in a consistent way to the latest steady-state solver. A new transient fixed source problem (TFSP) solver was developed without relying on the isotropic approximation of the angular flux time derivative. A moving axial mesh scheme was also implemented to model the control rod movement accurately with coarse axial meshes. In addition, in order to reduce the computational time further, an improved quasi-static method (IQM) solver and a predictor-corrector quasi-static method (PCQM) solver were developed in a consistent way to the TFSP solver. Initial verification tests were performed using the C5G7-TD benchmark problems. The results of the direct TFSP solver agreed very well with the MPACT and NECP-X solutions within ~2.5%. Additional analyses suggested that the observed differences are mainly due to the coarse time steps used in the MAPCT and NECP-X calculations. These results indicate that the direct TFSP solver of PROTEUS-MOC was correctly implemented and the moving axial mesh scheme is working properly. Numerical tests of IQM and PCQM against the direct TFSP solver showed that the IQM and PCQM solvers can reduce the computational time about 10 to 100 times without any significant loss of accuracy by allowing larger time steps. The PCQM calculation with the quadratic interpolation of kinetics parameters (KPs) showed the best performance among the four combinations of the IQM and PCQM solvers and the linear and quadratic interpolation schemes of KPs. This study also showed that the different delayed neutron precursor models of six and eight families can cause larger power differences than the different high-fidelity transient codes and that the adjoint scalar flux weighting can cause significant errors in KPs and subsequently in power evolution. In addition, the transient analyses of a modified C5G7 benchmark problem containing a void channel similar to the hodoscope channel of the Transient Reactor Test (TREAT) facility showed that the isotropic approximation of the angular flux time derivative can cause nonnegligible errors in the time-dependent power distribution. This study also demonstrated that PROTEUS-MOC can be used for transient analyses of reactors with internal void regions.

本文介绍了与最新的稳态求解器一致的方式开发的三种新型PROTEUS-MOC引脚解析瞬态求解器。在不依赖角通量时间导数的各向同性近似的情况下，开发了一种新的瞬态固定源问题（TFSP）求解器。还采用了移动轴向网格方案，以利用粗略的轴向网格来精确建模控制杆的运动。另外，为了进一步减少计算时间，以与TFSP求解器一致的方式开发了一种改进的拟静态方法（IQM）求解器和预测器-校正器拟静态方法（PCQM）求解器。初始验证测试是使用C5G7-TD基准测试问题进行的。直接TFSP求解器的结果与MPACT和NECP-X解决方案非常吻合，约为2.5％。其他分析表明，观察到的差异主要归因于MAPCT和NECP-X计算中使用的粗略时间步长。这些结果表明，PROTEUS-MOC的直接TFSP求解器已正确实现，并且运动轴向网格方案运行正常。针对直接TFSP求解器的IQM和PCQM的数值测试表明，IQM和PCQM求解器可以通过允许更大的时间步长来减少大约10到100倍的计算时间，而不会显着降低精度。在动力学参数（KPs）二次插值的PCQM计算中，IQM和PCQM解算器的四种组合以及KPs的线性和二次插值方案表现出最佳的性能。这项研究还表明，与不同的高保真瞬态代码相比，六族和八族不同的延迟中子先驱模型会导致更大的功率差异，并且伴随的标量通量加权可能会导致KP以及随后的功率演化中的重大误差。此外，对修改后的C5G7基准问题的瞬态分析表明，该问题包含类似于瞬态反应堆测试（TREAT）装置的全息通道的空隙通道，表明角通量时间导数的各向同性近似会导致随时间变化的不可忽略的误差电力调配。这项研究还表明，PROTEUS-MOC可用于具有内部空隙区域的反应堆的瞬态分析。