Enhancement of a subcritical experimental facility via MCNP simulations

At the University of Cincinnati Nuclear and Radiological Engineering Program, a once moth-balled vintage subcritical reactor facility was reassembled to provide a practical laboratory experience for students in nuclear science. The relative simplicity and accessibility of this facility are some of its most desirable features. Recent work had led to supplementing the experimental aspects of this facility with a three-dimensional, full detail, MCNP model of this reactor. This article emphasizes the latest validations of this simulation model against the most recently available laboratory measurements of neutron flux distributions and subcritical neutron multiplication factors, while illustrating a unique feature of this facility which enables experimentalists to carry out step by step measurements, and the corresponding simulations, while the core is being loaded and unloaded. Furthermore, additional simulations are herein included to evaluate the impact of different moderator and reflector arrangements upon core reactivity, including a few combinations of heavy water and/or beryllium, primarily as a venue for researchers to begin studying potential upgrades or changes to the current design.