Transient analysis of C5G7-TD benchmark with MPACT

Highlights: • Thorough analysis on all the cases in C5G7-TD benchmark. • Parametric study on the time step size. • Comprehensive comparison with other codes' results. - Abstract: Verification and Validation (V&V) serves an important role in assessing the numerical methods implemented in a neutron transport code. However, very few benchmarks are available for verifying and validating the transient capability of neutron transport codes. In this paper, the transient methodology of the Transient Multilevel (TML) Method used in the MPACT code was verified using Phase I of the recently developed OECD/NEA C5G7-TD benchmark, which was specifically designed for validating the transport space-time simulations. The results in MPACT agree well with results of other codes. While this is not code validation, the results contributes to the MPACT verification base and provide an additional solution for the C5G7-TD benchmark which can increase the importance of the OECD benchmark to assess the performance of other transient neutron transport codes.