An Analysis of Flux Fine Structure in One-Dimensional Fast Reactor Cells

An analysis of the BNL heterogeneity experiment is described in this paper. The nuclear data used are based on ENDF/B Versions I and II and the DSN method is used in the analysis. In addition to determining the intracell fine structure for ²³⁵U and ²³⁸U fission and Mn capture, the variation of absolute ²³⁵U/²³⁸U fission ratio as a function of cell size is investigated. From these results it can be concluded that the fission ratio calculations are particularly sensitive to the fission cross section of ²³⁵U and ²³⁸U, suggesting that measurements of this type could be useful in checking the accuracy of data. The overall agreement between computed and measured quantities was found to be good for all quantities that could be characterized as asymptotic. The non-asymptotic nature of some quantities is investigated using two-dimensional calculations.