The neutron transport solution using Daubechies' wavelet discretization in the angular domain

Daubechies' wavelet expansion is introduced to discretize the angular variable of neutron transport equation. A coupled angular discretization scheme based on the wavelet expansion and discrete ordinate method is applied. Anisotropic scattering is considered and three-dimensional calculation is taken by use of the coupled scheme. In order to perform the calculation on unstructured geometries, the FEM (finite element method) is applied in the spatial discretization. The boundary conditions are exactly solved by dividing the angular domain into eight angular sub-domains in the three-dimensional calculation. A set of wavelet equations coupled with each other is obtained in each sub-domain and it is decoupled by an iterative method. The numerical results demonstrate that the wavelet expansion method and the coupled angular discretization scheme are feasible and accurate. (authors)