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Perpetual Atomics, QSA Global produce Am fuel for nuclear space power
U.K.-based Perpetual Atomics and U.S.-based QSA Global claim to have achieved a major step forward in processing americium dioxide to fuel radioisotope power systems used in space missions. Using an industrially scalable process, the companies said they have turned americium into stable, large-scale ceramic pellets that can be directly integrated into sealed sources for radioisotope power systems, including radioisotope heater units (RHUs) and radioisotope thermoelectric generators (RTGs).
Karmeshu, N. K. Bansal
Nuclear Science and Engineering | Volume 58 | Number 3 | November 1975 | Pages 321-327
Technical Paper | doi.org/10.13182/NSE75-A26781
Articles are hosted by Taylor and Francis Online.
The exact expressions for the first- and second-order moments of neutron density and the delayed-neutron precursor density are derived for a neutron multiplying system, with time-dependent stochastic perturbations in the reactivity and white noise source. The effect of finite correlation time of the reactivity on the stability of moments is discussed. For asymptotically long times, the moments are found to be stable. The exact expressions of the moments in the limiting case, when the reactivity correlation time becomes zero, are also derived. It is found that the expressions for this limiting case differ from the corresponding expressions of Williams.