HANDBOOK OF SHIELDING REQUIREMENTS AND RADIATION CHARACTERISTICS OF ISOTOPIC POWER SOURCES FOR TERRESTRIAL, MARINE, AND SPACE APPLICATIONS

The radiation intensities from shielded and unshielded sources fabricated from seventeen isotopes that show promise for use in isotopic power or radiation applications were calculated. Source sizes in the range of 100 to 20,000 thermal watts were evaluated. All shielded sources were assumed to be attenuated by Fe, Pb, and U; and in those cases where the source also emitted neutrons, neutron and gamma attenuation through water was determined. The isotopes studied and their physical form are as follows: /sup 60/Co (metal), /sup 85/Kr (liquefied gas), /sup 90/Sr (oxide and titanate), Zr-/sup 95/Nb (oxide), / sup 106/Ru (metal), /sup 137/Cs (glass), /sup 144/Ce (ox ide), /sup 147/Pm (oxide), /sup 170/Tm and /sup 171/Tm (both as oxides), /sup 204/Tl (metal), /sup 210/Po (metal matrix with void space for gas collection), /sup 232/U (oxide), /sup 228/Th (oxide matrix with void space for gas collection), /sup 238/Pu (oxide), /sup 242/Cm (oxide matrix with void space for gas collection), and / sup 244/Cm (oxide). The use of the graphical results to calculate separation distance, shield thickness, and shield weight is demonstrated. (auth