Standard reference data for gamma-ray transport in homogeneous media. [PWR; BWR]

An American Nuclear Society Standards Committee Working Group, identified as ANS-6.4.3, is developing a set of evaluated gamma-ray isotropic point-source buildup factors and attenuation coefficients for a standard reference data base. As a first step, a largely unpublished set of buildup factors calculated with the moments method is being evaluated by recalculating key values with Monte Carlo, integral transport, and discrete ordinates methods. Attention is being given to frequently neglected processes such as bremsstrahlung and the effect of introducing a tissue phantom behind the shield. The proposed standard will contain data for a source energy range from 15 keV to 15 MeV and for approximately 12 elements and 3 mixtures (water, air, and concrete).