Background cross section approach to generating group constants for shielding calculations

The background cross section method is evaluated for applications in shielding analysis. It is shown that approximations used in the standard method are inadequate for deep penetration in nearly pure materials and for problems in which elastic removal is important. Three improvements are proposed and tested: buckling iteration to improve leakage calculations, improved elastic removal iteration, and explicit self-shielding of all elements and Legendre orders of the elastic matrix. 2 figures, 2 tables