Warning on missing photon spectra for neutron-photon simulations

[marquezj]

Description

OpenMC currently supports neutron-photon simulations, but not all the data files contain secondary photon distributions. One important case is the Cd-113 evaluations in ENDF/B. This is a silent error, because the user will make the neutron-photon simulation and some photons will appear, but the gamma flux and dose will be underestimated.

If you try this in MCNP it gives a warning (warning. 48113.70c lacks gamma-ray production cross sections.). Something like this could be done in OpenMC, if settings::photon_transport is enabled and the products array is empty for the MT=102 (radiative capture) and MT=3 (total inelastic) reactions. Maybe there are other photon emission reactions that should be monitored.

Alternatives

The alternative is to do nothing and leave to the user to use the proper data library.

Compatibility

There are no compatibility issues.

[yrrepy]

I think these kinds of warnings would be more useful than the terminal print that OpenMC is loading abc.h5 neutron cross-section.