An adaptive general multigroup method

In the multigroup transport equation, the subdivision of the continuous energy domain is approximated using a finite number of energy groups. The generation of group cross sections is predominantly performed using the traditional multigroup method (1). A new approach is presented that sheds the traditional definition of energy groups. The new method allows an energy to have partial membership in more than one group, which allows the assumed group spectral shape to adapt to problem-dependent conditions. It will be applicable in criticality safety studies because it allows for more accurate fission neutron spectrum and spatial variation in the flux spectrum inside a homogeneous material