SUBJECT: M.S. Thesis Presentation
BY: Spenser Lewis
TIME: Friday, December 13, 2013, 9:00 a.m.
PLACE: Boggs, 3-47
TITLE: Simplified Core Physics and Fuel Cycle Cost Model for Preliminary Evaluation of LSCR Fueling Options
COMMITTEE: Dr. Bojan Petrovic, Chair (NRE)
Dr. Glenn E. Sjoden (NRE)
Dr. Weston M. Stacey (NRE)
Dr. G. Ivan Maldonado (NE)


The LSCR provides many benefits compared to other reactor systems. These include low operating pressure of the liquid salt coolant, the high burnup tolerance of the fuel, and the high operating temperatures which leads to increases in efficiency. However, due to inherently low heavy metal loading, the fuel cycle design presents specific challenges.

In order to study options for optimizing the fuel design, SCALE6.1 was used to create simplified models of the reactor and look at various parameters. The primary parameters of interest included packing factor and fuel enrichment. An economic analysis was performed on these results by developing a simple FCC model that could be used to compare the different options from an economic standpoint.

There was also effort applied towards looking at the lithium enrichment of the FLiBe coolant. The main focus was to understand the practical limitations associated with the Li-7 enrichment and whether it could be used for beneficial purposes. The main idea was to determine whether a lower enrichment could be used at reactor start up so that the Li-6 isotopes act as a burnable absorber.

The results found through this research provide reasonable guidelines for expected costs and the types of configurations that should be avoided entirely when considering fuel design options for the LSCR. Additionally, knowledge was gained on methods for modeling the system not only accurately but also efficiently to reduce the required computing power. The results for the lithium enrichment study showed that the enrichment converges over time, but the amount of time required to reach steady state is much too long and the FLiBe coolant could not be utilized for reactivity control as a burnable absorber.