Component-level Performance and Mass Sensitivity Analysis of NEP MW-class Power System

Nuclear electric propulsion (NEP) is a promising option towards enabling missions to Mars
and is an area of interest for NASA’s Space Nuclear Propulsion project. This project is
currently investigating technology development opportunities for an NEP vehicle. Physics-based modeling can be used in the early stages of technology development to gain
understanding of the effects of technology and performance assumptions on the system
performance and mass. This information can then inform technology maturation planning for
near term development. By using a Brayton power conversion model and vehicle mass model
for megawatt class NEP applications, a sensitivity analysis is performed to assess the impact
of individual components’ performance on the power conversion system performance and
system mass. A Monte Carlo simulation is also used to determine the variability in system
mass based on uncertainty within the modeling parameters. The sensitivity analysis shows a
high sensitivity to power conversion inlet temperature, compressor inlet temperature, and
recuperator performance. A Monte Carlo analysis suggests a range of -10% to +15% for a
90% confidence interval on system mass based on the uncertainties in the model inputs.