Table 1. Results of ANISN benchmark calculations with Hansen-Roach 16-energy-group cross section data

DOE-STD-3007-93

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

PNL-7.

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.

Table 1.

Results of ANISN benchmark calculations with Hansen-

Roach 16-energy-group cross section data.

ANISN

Calculated

Benchmark

Description

H/Pu-239

k-effective

PNL-1

Bare sphere

700

1.0051

PNL-2

Bare sphere

131

1.0069

PNL-3

Bare sphere

1204

0.9918

PNL-4

Bare sphere

911

0.9985

PNL-5

Bare sphere

578

0.9979

PNL-7

Reflected

980

1.0023

sphere

4-10