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Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Mikio Sakai, Kazuya Shibata, Seiichi Koshizuka
Nuclear Science and Engineering | Volume 154 | Number 1 | September 2006 | Pages 63-73
Technical Paper | doi.org/10.13182/NSE06-A2618
Articles are hosted by Taylor and Francis Online.
Particle dynamics of nuclear fuel material has not been considered in conventional nuclear criticality evaluations. However, the particle motion influences nuclear criticality significantly. In the present study, the criticality calculation is combined with the discrete element method (DEM) to investigate the effects of the particle macroscopic behavior on nuclear criticality. Particle motion is analyzed in a rotating drum by the DEM, and then, the nuclear calculation is carried out. This paper focuses on particle size distribution, size segregation, and change of surface area of the particle bed. The particle size distribution has an important influence on the nuclear criticality evaluation because it affects not only the particle movement but also the atomic number densities in the bed. The surface area of the particle bed shows a close correlation with the multiplication factor. On the other hand, the size segregation does not have a significant effect on nuclear criticality.