MOSART Core Neutronics in Serpent

[katyhuff]

This issue can be closed when a simple full core model of the MOSART reactor has been run with Serpent on Blue Waters.

• [x] Start with serpent input file for similar reactor
• [x] Define geometry
• [x] Define materials
• [x] Run simulation

[anshchaube]

Preliminary runs demonstrated that MOSART cannot be critical with the given dimensions and fuel composition. Further investigation discontinued.

[katyhuff]

Thanks @achubbz