Fuel cycle cost comparison between lead and sodium cooled fast reactors

Abstract

Sodium and lead coolants are the most recognized coolants for Liquid Metal-cooled Fast Reactor (LMFR). The two coolants have significantly different physical, thermal and chemical properties, which results in major core design differences between lead- and sodium-cooled systems. This work attempts to quantify the impact of the coolant type on the fuel cycle cost of a LMFR by comparing the Levelized Fuel Cycle Cost (LFCC).The paper is composed of two studies with the goal of comparing the advantage of the superior neutronic performance of lead versus the advantage of the tight lattice that can be achieved with sodium coolant. In the first study, the influence of the neutronic differences between lead and sodium on the fuel cycle cost are isolated and quantified. This is achieved by comparing the fuel cycle performance of a Lead-cooled Fast Reactor (LFR) core model to that of a Non-optimized SFR (NSFR) model. The two models have a similar geometry, fuel loading, fuel type, and structural materials. The only major difference between the two cores was the coolant (i.e. lead vs. sodium). Based on this comparison, it is shown that the better neutronic performance of lead coolant results in longer cycle length for the LFR core. It is also shown that this difference in cycle length can result in up to 30.8% better LFCC for a lead-cooled system compared to a sodium-cooled one. In the second study, a Sodium-cooled Fast Reactor (SFR) is designed that is optimized for the sodium coolant. The design process for the Long-life core Sodium Fast Reactor (LSFR) realizes the compatibility of sodium coolant with structural materials and allows for a more compact design. The design parameters and constraints of the design are presented, and the objective of the design is to reduce the LFCC. In this study, the design with the sodium coolant offers a 2% reduction in the LFCC, along with a smaller core size.The overall results show that if you compare sodium and lead using the same reactor geometry, the neutronic benefits of lead coolant can lead to a 30% reduction in the LFCC. However, if you optimize the geometry to take advantage of the higher power density allowed with sodium coolant, the sodium coolant can offer a 2% LFCC reduction or a smaller core size.