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May 31–June 3, 2026
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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).
L. L. Briggs, E. E. Lewis
Nuclear Science and Engineering | Volume 63 | Number 3 | July 1977 | Pages 225-235
Technical Paper | doi.org/10.13182/NSE77-A27035
Articles are hosted by Taylor and Francis Online.
A new coarse-mesh technique, the constrained finite element method, is formulated from the variational form of the even-parity transport equation: Linear finite elements in space are combined with a P1 constraint on the angular trial functions at selected nodes to obtain a coarse-mesh three-point difference scheme for the scalar flux. Beginning with the same variational form of the transport equation, response matrix equations are derived that differ from the constrained finite element method only in the angular approximation made at the coarsemesh nodes. The two techniques are compared to each other, to S8 reference solutions, and to diffusion calculations for a number of one-group slab geometry problems involving both homogeneous media and lattice cells; they are found to be of comparable accuracy and efficiency. The generalization of the constrained finite element method is discussed.