Wavelet expansion method

The wavelet expansion method is widely used in various fields due to its powerful ability to simulate the oscillating function. This method is applied to discretize the energy variable of neutron angular flux within the resonance energy range. Meanwhile, the conventional multigroup method is applied in fast, thermal energy ranges. This coupled method can obtain the problem-dependent, continuous-energy neutron spectrum within resonance energy range. The method of characteristics is employed as a space-variable solver in this method to keep the powerful capability of dealing with the complex geometry problems. Numerical results show that this is a valuable method to solve the resonance self-shielding calculation problem with complex geometry, and its potential is promising as applied to realistic reactor problems.