The Department of Energy recently announced a $47 million, three-year funding package for collaborative research efforts involving tokamaks (machines that confine a plasma using magnetic fields in a donut shape for fusion). NPRE associate professor Davide Curreli’s research evaluating the viability of tungsten as a plasma fusion component is one of the projects being funded in this package.
Curreli will be continuing this work in collaboration with researchers at Penn State University, the University of Tennessee, Princeton Plasma Physics Lab, and Oak Ridge National Lab.
“You need an element that is stiff, tough, robust,” Curreli said. “Tungsten is all of those things, but it is a critical beast to handle. The plasma doesn’t like it.”
Curreli’s group will handle the computational modeling for the experiments done at WEST (Tungsten (W) Environment in Steady State Tokamak), located in France. WEST is an integrated platform for the testing and development of actively-cooled, W Plasma Facing Components (PFCs) under combined heat and particle loads. Demonstrating the sustainability of plasma scenarios over relevant plasma wall equilibrium timescale (more than 100 seconds), as required for steady-state operation, requires integrating the science and technology for scenario control and is an essential step to understanding and preparing for the operation of the future devices, e.g., a fusion pilot plant (FPP).
For this purpose, WEST is paving a path towards actively-cooled tungsten PFCs under prototypical loads (particularly for the ITER divertor) and at mastering integrated plasma scenarios over relevant plasma wall equilibrium timescales in its full tungsten environment. WEST is an international facility, with partners from China, Europe, India, Korea, and the US, and provides an opportunity to confront these unknowns and identify solutions on the way to long pulse operation before they are encountered in future devices.
Computer model of the internal chamber of the WEST tokamak at CEA Cadarache, France, showing the tungsten lower target and the RF antenna systems.
[cr][lf]The main aim of this project is to address the impact of tungsten (W) as the main plasma facing material (PFM) armoring plasma-facing components (PFCs), in particular for the actively-cooled, long-pulsed, divertor tokamak. This project will focus on integrated analysis to predict and optimize plasma material interactions (PMI) and edge plasma conditions, as well as to investigate approaches for long pulse operations.
Tungsten is a leading candidate PFC in next-step fusion devices for its high resilience to sputtering at the nominal conditions of the wall in fusion devices, particularly as they progress to reactor conditions. These properties lead to a sufficient lifetime of the W components under the hours of plasma exposure expected, as well as negligible or small long-term retention of the hydrogenic fuel (which will eventually contain tritium) in these components. The WEST tokamak provides a full W PFM environment compatible with long pulse operation to help develop and benchmark a full range of PMI modeling codes, i.e., over large time- and length-scales [Gilbert 2021].
“We must continue to provide innovative solutions to the most urgent challenges facing fusion energy and advance the state of the art across fusion and plasma sciences,” said Harriet Kung, Acting Associate Director of Science for Fusion Energy Sciences in the DOE’s release.
“These activities will make optimal use of existing tokamak facilities and provide productive engagements with leading fusion institutes, moving us closer to fusion energy as a clean and abundant energy source.”