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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.
S. P. Congdon, M. R. Mendelson
Nuclear Science and Engineering | Volume 33 | Number 2 | August 1968 | Pages 151-161
Technical Paper | doi.org/10.13182/NSE68-A20653
Articles are hosted by Taylor and Francis Online.
The derivation of blackness boundary conditions is reviewed and generalized into a standard matrix formalism that is valid for any order PN approximation. It is then shown that for a finite slab effective diffusion and absorption matrices can be found which reproduce blackness boundary conditions at the interfaces. In the continuous or infinitely many mesh point description of the black region, the analysis leads to infinite series expressions for the equivalent matrices, which have been evaluated explicitly by means of the Caley-Hamilton theorem for the case of the P 3 approximation. Equivalent matrices have also been derived for two- and three-mesh-point descriptions of the black region. Numerical calculations for three model problems indicate that P3 blackness theory is a great improvement over conventional P3 theory and is roughly equivalent to P5 theory in the prediction of both the exterior scalar flux and the absorption rate in the black region.