H/Pu ratios range from 131 to 1204 for the benchmarks. H/Pu ratios range from
700 to 1100 for this analysis. Optimum values occurred between 800 and 900 for
reflected systems. The predominant cross section data for Pu-239 at optimum
conditions are associated with Hansen-Roach Library ID 94913. Hansen-Roach
Library ID 94913 is used for analysis of experiments PNL-1, PNL-3, PNL-4, and
All ANISN benchmark calculations were performed with a quadrature order of 8 and 100
mesh intervals in the fuel region. For PNL-7, 100 mesh intervals were also represented in the
reflector region with 10 mesh intervals in the thin stainless steel wall.
The results of the ANISN benchmark calculations with Hansen-Roach 16-energy-group
cross section data are summarized in Table 1.
The results of the ANISN calculations agree well with the experimental values(1.0). The
largest deviation occurs for PNL-3 with an H/Pu ratio of 1204 and agreement in this case is
within 0.8%. Results for PNL-1, PNL-4, and PNL-7 indicate little (less than 0.15%) or no bias
for H/Pu ratio between 700 and 900 (enveloping optimal values of this evaluation). Inclusion of a
bias of this magnitude is inconsequential [Note: A more detailed bias determination is often
required]. There are no statistical uncertainties associated with Sn discrete ordinates methods.