Development of the neutronics transport code based on the MOC method and adjoint-forward Coarse Mesh Finite Difference technique: PerMOC code for lattice and whole core calculations

Highlights: • The Method of Characteristics is applied as a new transport code called PerMOC. • Both forward and adjoint CMFD acceleration techniques are applied to the MOC kernel. • A newly proposed adjoint solver reduces about 30% the number of transport sweeps. • More speed-ups are achieved using a parallel transport sweeping in the MOC kernel. • The calculated reactivity of 2D C5G7 benchmark has only 51pcm error with the reference. - Abstract: In this research, the Coarse Mesh Finite Difference (CMFD) acceleration technique in both adjoint and forward mode is applied to the MOC kernel, to develop a new code called PerMOC. A new approach in the adjoint MOC kernel which is called thermal-up-scattering-like iteration scheme reduces the total number of adjoint iteration sweeps. In additions, more speed-up is achieved using a parallel transport sweeping in MOC kernel. Validation test for PerMOC C-Sharp code is carried out for four distinct criticality benchmarks in which C5G7 is one of those. In the case of C5G7 benchmark, the best-calculated multiplication factor has 51 pcm differences with the reference case. Furthermore, the newly proposed adjoint solver reduces about 30% the number of adjoint transport sweeps in comparison with the normal adjoint solver. The present article describes the PerMOC methodologies and illustrates its ability to model large problems with acceptable accuracy.