Neutronics Simulations of Graphite Experiments

Abstract

A widely used method for Neutronics simulations is MCNP6. Throughout this work, multiple MCNP6 simulations were completed on different supercomputers. These simulations entailed realistic representations of experiments being completed. The IM1 configuration was simulated with the corrected source definition. This geometry resulted in 0.222 as the graphite to air ratio. The IM1 experiment required many different configurations to be modeled in MCNP6. In order to further characterize the experiment different boric acid concentrations were poured in a beaker. The boric acid concentration produced an exponential fit, this represented the decrease in absorptions per second as the boric acid concentration was increased. With the progression of the project a more complex problem was created. This year 5 geometry was approached primarily through a straightforward stacked air duct problem. These results concluded that with the addition of a more complex geometry MCNP6 would require many neutron particle histories and become computationally expensive. Finally, in anticipation of the arrival of the neutron generator safety calculations were completed. These calculations yielded an estimated dose of 107.04 ± 0.3 mrem per hour in the entrance way during operation. The estimated dose was less than 5 mrem per hour in every other location of concern. The geometries were developed in MCNP6 and converted into PDT readable formats. This work was completed in order to aid in the validation of PDT development.