Session: Rising Stars of Mechanical Engineering Celebration & Showcase

Paper Number: 150761

150761 - Holistic Investigations of Molten Salt Fusion Energy Systems: System and Component Design Using Computational and Experimental Methodologies 

Recently, the interest in fusion energy has involved both public and private support including $2+ billion of private capital. For deployment of any fusion energy system, the fusion enabling technologies in, out, and around the plasma facing components are needed to ensure power production is achievable. For molten salt based blanket systems, known as liquid immersion blankets (LIB), the key maturation of fusion enabling technologies is needed for heat removal, transfer, and power conversion. These enabling technologies for a LIB include 1st wall cooling of the plasma confining vacuum vessel, breeder blanket heat removal system, and power conversion system. For proposed LIBs, the molten salt, FLiBe, is the lead candidate salt and was previously used in the Molten Salt Reactor Experiment at Oak Ridge National Laboratory. It was selected for fusion energy systems due to the ability to breed the fusion energy systems’ fuel, tritium, based on the lithium contained in the salt. FLiBe does present a challenge of a high melting/freezing point, toxicity concerns, and overall high cost per unit mass. Further, the historical challenges within the 1st wall of a fusion energy system includes extremely high heat fluxes of 1-10s of MW/m2 and a highly electromagnetic environment that can lead to adverse magneto-hydrodynamic effects in the molten salt. To address these challenges, we have begun our efforts to develop meaningful system modeling of a prototypical LIB based on the ARC concept. The LIB system model is being developed in the DOE System Analysis Module (SAM) code, and we have used it to explore start-up, steady-state, and shutdown scenarios. Using this system model, we are generating expected operational conditions for normal and off-normal operational modes. From this information, we are doing component-level scaling analysis to create scaled state-of-the-art experiments with complementary high-fidelity computational fluid dynamics (CFD) analysis. The scaling analysis provides the ability to use both water and specific mineral oils as surrogates for molten salts (FLiBe) at a lab scale.

In this work, we are focusing on the 1st wall coolant channel components where heat removal is enhanced using twisted tape-inserts. Within the 1st year of this DOE Early Career Research Project, we have successfully visualized flow in water within twisted-tape inserts with increasing gap-width using the positron emission particle tracking (PEPT) flow visualization technique. Using this information, we have successfully shown the existence of vortical structures using PEPT within laminar to turbulent flow regimes that will impact heat removal. We have also measured thermal performance in water of the Nusselt number and Darcy friction factor for varying Reynolds numbers and twisted tape-inserts geometric parameters. In a complementary fashion, we have used the DOE Nek5000/NekRS CFD code to do large eddy simulations (LES) of twisted tape-inserts for both the CFD validation to previous experiments and for developing multiphysics simulations of 1st wall coolant scenarios. Future LES of the twisted tape-inserts will focus on predicting the previously observed vortical structures in same the geometries and flow conditions. 

In this presentation, we will discuss our current progress in this multifaceted DOE Early Career Research Project and how we are addressing the development challenges to support LIB based fusion energy system deployment.

Presenting Author: Lane Carasik Virginia Commonwealth University

Presenting Author Biography: Dr. Lane Carasik is an Assistant Professor within the Department of Mechanical and Nuclear Engineering at VCU. Dr. Carasik is the Director of the Fluids in Advanced Systems and Technology (FAST) research group that does computational and experimental thermal hydraulics research in advanced energy systems. He was previously an engineer at Kairos Power and Ultra Safe Nuclear Corporation. Dr. Carasik has a Ph.D. in Nuclear Engineering from Texas A&M University and a B.S. in Nuclear Engineering from the University of Tennessee, Knoxville. In July 2023, Dr. Carasik is a Department of Energy Office of Science Early Career Research Program awardee focused on molten salt fusion energy systems development. Dr. Carasik has ongoing experimental and computational efforts that support design and licensing activities for molten salt reactors and sodium fast reactors. This experience includes experimental efforts using scaled surrogate separate effects facilities, high-fidelity CFD modeling including RANS modeling, and LES with Nek5000/NekRS. As part of his research and educational activities, Dr. Carasik focuses on serving underserved and underrepresented students at VCU and the overall nuclear community through serving as the previous Chair of the Diversity and Inclusion in the ANS Committee. Several of Dr. Carasik’s current and past graduate and undergraduate researchers are part of these underserved & underrepresented communities. Additionally, Dr. Carasik was a co-recipient of the 2020 American Society of Mechanical Engineers (ASME) FED Moody and 2018 ASME CFD Best Paper Awards for work completed while employed at Kairos Power on a Department of Energy (DOE) GAIN Voucher.

Authors:

Lane Carasik Virginia Commonwealth University
Sierra Tutwiler Virginia Commonwealth University
Trevor Franklin Virginia Commonwealth University
Ryan Mcguire Virginia Commonwealth University
Arturo Cabral Northrop Grumman