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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.
Tomasz Kozlowski, Yunlin Xu, Thomas J. Downar, Deokjung Lee
Nuclear Science and Engineering | Volume 169 | Number 1 | September 2011 | Pages 1-18
Technical Paper | doi.org/10.13182/NSE08-85
Articles are hosted by Taylor and Francis Online.
For practical reactor core applications, low-order transport approximations such as SP3 have been shown to provide sufficient accuracy for both static and transient calculations with considerably less computational expense than the discrete ordinate or the full spherical harmonics methods. These methods have been applied in several core simulators where homogenization was performed at the level of the pin cell. One of the principal problems has been to recover the error introduced by pin cell homogenization. One of the basic approaches to treat pin cell homogenization error is pin cell discontinuity factors (CDFs) based on well-established generalized equivalence theory to generate appropriate group constants. The method is able to treat all sources of error together, allowing even a few-group diffusion solution with one mesh per cell to reproduce a higher-order reference solution. However, a CDF has to be derived separately for each space-angle approximation. An additional difficulty is that in practice the CDFs have to be derived from a lattice calculation from which only the scalar flux and current are available, and therefore recovery of the exact SPN angular moment is not possible. This paper focuses on the pin cell scale homogenization. It demonstrates derivation of the CDF for the SP3 transport method with finite-difference spatial discretization with the limitation of only the scalar flux and interface current being available from the heterogeneous reference. The method is demonstrated using a sample benchmark application.