This topic has been migrated from the SCALE
6 notebook.
Date: Mon Mar 26 13:36:40 2012
A few minor issues were identified with the SCALE fixed-source Monte Carlo code Monaco and an associated utility, especially related to seldom-used optional features. These features will be corrected in a pending patch for SCALE. These features should be used with caution until the patch is applied.
• When specifying the special distribution pwrNeutronAxialProfileReverse or pwrGammaAxialProfileReverse for a spatial source distribution, the un-reversed profile is erroneously returned.
Impact: This is a seldom-used feature that was implemented for compatibility with previous MORSE calculations. Problems run using one of the special axial distributions containing the word reverse are in fact not reversed, and erroneous results could result due to an inaccurate source specification.
• The sum of the point detector group-wise results may be higher than the point detector energy-integrated (total) results. The reported total is correct. The group-wise values are high due to rejecting negative contributions (which happen a small fraction of the time due to the multi-group energy/angle physics).
Impact: The energy-integrated results are correct. Only energy-dependent results are in error for some calculations. If the use of energy-dependent results is desired, users should verify that they sum to the total value.
• If a source specification utilizes different Watt spectra distributions in multiple sources, the energies sampled for one source may include energies from the wrong distribution.
Impact: Only models that implement more than one Watt spectrum are impacted. Since Watt spectra from different isotopes are quite similar, the impact of this discrepancy may not be noticeable. For Watt spectra that are very different, results may differ.
• The utility program mim2wwinp does not format MCNP *.wwinp files correctly for photon-only problems. MCNP interprets a *.wwinp with only one particle listed as neutrons, even in a "mode p" problem. The *.wwinp file produced by SCALE needs to specifically identify that there are 0 neutron groups for photon-only problems.
Impact: Subsequent MCNP calculations that use the SCALE generated .wwinp files for photon-only problems will not run.
Date Identified: 3/22/2012
