what caused it? and what does it translate to
This warning indicates that some nuclide present in your model has cross sections that only go up to an energy less than 20 MeV. The only case I know of is Be7 from ENDF/B-VII.1, which is an erroneous evaluation that goes up to 8.1 MeV. This would only be a problem if you are trying to simulate particles with energies above 8 MeV (e.g., a D-T neutron source at 14 MeV). If it is indeed Be7 that is causing this warning, you can try removing Be7 from your model. If it is being inserted during depletion, you can remove it from the depletion chain file.
1 Like