If the plutonium recovered from discharge fuel by fuel reprocessing is stored for long periods, there is a loss of fuel value due to the radioactive decay of fissile 241 Pu. Even during storage periods as short as a few months, 241 Am, the beta-decay daughter of 241 Pu, builds up. Its decay is accompanied by gammas that increase the shielding fequired in the fabrication of fuel from recycled plutonium. Small quantities of 237U, formed by the alpha decay of 241 Pu, also increase the gamma activity. The decay of 2.85-year 236Pu forms 232U, 228Th, and short-lived decay daughters that also contribute to the shielding requirement. The growth of radioactive daughters in plutonium recovered from the fuel discharged each year by the uranium-fueled 1000-MWe LWR of Fig. 3.31 is shown in Fig. 8.6 [PI]. The radioactivity of the 228Th daughters, which will be in secular equilibrium with 228Th, is not included.