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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.
Anil Kumar, M. Srinivasan, K. Subba Rao
Nuclear Science and Engineering | Volume 84 | Number 2 | June 1983 | Pages 155-164
Technical Note | doi.org/10.13182/NSE83-A17722
Articles are hosted by Taylor and Francis Online.
The Trombay criticality formula (TCF) has been derived by incorporating a number of well-known concepts of criticality physics to enable prediction of changes in critical size or keff following alterations in geometrical and physical parameters of uniformly reflected small reactor assemblies characterized by large neutron leakage from the core. The variant parameters considered are size, shape, density and diluent concentration of the core, and density and thickness of the reflector. The mass-to-surface-area ratio of the core, is essentially a measure of the product ρr extended to nonspherical systems and plays a dominant role in the TCF. The functional dependence of keff on σ/σc, the system size relative to critical, is expressed in the TCF through two alternative representations, namely the modified Wigner rational form and the exponential form as follows: where is the k∞ of the critical system. The quantity in the square brackets is close to unity and Z is a parameter weakly dependent on both the physical and geometrical properties of the core, where θ = ln[/( - 1)] and ε is a parameter introduced to account for the steep rise in the net leakage probability for highly subcritical cores. The applications of the TCF range from the quick computation of the keff of a lump of fissile fuel having arbitrary shape and density through the study of keff of highly enriched fissile materials during transportation accidents to an estimation of the void and fuel expansion coeffficients of reactivity in high leakage systems.