Calculation of the Thermal Disadvantage Factor in a Heterogeneous Slab Cell

An analytical expression for calculating the disadvantage factor in a heterogeneous slab cell is derived by solving the one-speed neutron transport equation using a one-term scattering kernel (isotropic scattering). The expression derived is based on the method of spatial expansion developed by Pomraning and Clark. The numerical results appear to be very good compared with the other high-order approximate and exact methods.