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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).
D. K. Olsen, G. de Saussure, R. B. Perez, E. G. Silver, F. C. Difilippo, R. W. Ingle, H. Weaver
Nuclear Science and Engineering | Volume 62 | Number 3 | March 1977 | Pages 479-501
Technical Paper | doi.org/10.13182/NSE77-A26986
Articles are hosted by Taylor and Francis Online.
The transmissions of 0.52- to 4000-eV neutrons through 3.62-, 1.08-, 0.254-, 0.0762-, 0.0254-, 0.0127-, and 0.0036-cm-thick samples of uranium, enriched in the 238U isotope, have been measured at 42 m with a 1.0-mm-thick 6Li glass detector using the Oak Ridge Electron Linear Accelerator pulsed neutron source. To obtain resonance parameters, the seven transmissions of neutrons having energies ranging from 0.52 to 1086.8 eV have been shape-fitted by least-squares analysis to a multilevel Breit-Wigner cross-section formalism with “picket-fence” terms to account for truncation effects. This simultaneous fit yielded a χ2 per degree of freedom near unity. Averaged over this energy range, an s-wave strength function of (0.968 ± 0.036) × 10-4 cm and an effective radius of (0.944 ± 0.005) × 10-12 cm were obtained. In addition, these transmission data yielded an average radiation width of 23.1 ±1.0 meV for the 12 lowest energy s-wave resonances with radiation widths of 23.0 ± 0.8, 22.8 ± 0.8, and 22.9 ± 0.8 meV for the 6.67-, 20.9-, and 36.8-eV resonances, respectively. The derived radiation widths for these three resonances are shown to depend on the cross-section formalism employed. This work suggests that a multilevel formalism with truncation compensation is required to adequately represent the 238U total cross section.