232U, 228Th, 227Ac, and 226Ra primary radioisotopes: High-power sources for nuclear batteries

The present communication deals with the evaluation of the cumulative energy produced by the sequential α- or α- and β−-decay processes of 232U, 228Th, and 226Ra isotopes, ending in the β−-decaying 212Pb or 210Pb isotopes, and by the β‒ of 227Ac, which ends in the 211Pb isotope. The obtained results evidence that the overall decay chains greatly contribute to total specific power and total specific energy released by these radioactive sources. The actual maximum power as well as the total specific energy available at selected times are found from two to four times higher than those expected when, as usual, only the parent-to-daughter decay of 232U, 228Th, 226Ra and 227Ac are taken into consideration. The present analysis enabled to underline the rather complex trends of both total specific power and total specific energy as a function of elapsed time. It has been also evidenced that the decay processes initiated by the alpha-emitting 232U, 228Th, 226Ra and by the beta-emitting 227Ac isotopes occur actually by the sequential emission of different kinds of radiations. These concepts contribute to establish the physical viability of such nuclides for the powering of nuclear batteries and have significant implications on the technology of such devices.