Shielding Calculation Techniques for the Design of Plutonium Processing Facilities

Techniques have been developed for the shield design computations of facilities for the handling and processing of plutonium. These techniques involve the application of a modified version of the point kernel code QAD. Because this modified point kernel code maintains the three-dimensional flexibility and computational efficiency of other point kernel codes, it is well suited to the performance of production shielding-design calculations. Correction factors were developed to account for some inadequacies of the point kernel approach. The accuracy of the code has been determined by comparing results obtained for typical shield configurations with ANISN results and has been found to be adequate for most shielding problems encountered in facilities of this type. Limited comparison to available experimental data indicates the techniques give reasonably good accuracy. Sources of radiation considered include neutrons and gammas from fission, neutrons from (α, n) interactions with light elements, and low-energy gammas from alpha decay.