The Materials Plasma Exposure eXperiment (MPEX) and the challenges of engineering for fusion in steady-state

Arnold Lumsdaine

Oak Ridge National Laboratory

Thursday, April 15, 2021

2:00pm

Virtual

PSFC Seminars

Abstract: Understanding the consequences of plasma material interactions is a necessary step towards the development of next-step fusion facilities [1].  The Materials Plasma Exposure eXperiment (MPEX) is a linear plasma facility that is proposed to test neutron irradiated materials under plasma conditions relevant for divertors in future fusion facilities [2].  The design of MPEX and the operation of its precursor, Proto-MPEX, has involved the selection of materials and instrumentation to manage heat the linear plasma and its various heating sources.  For MPEX, this is expected to be a total of 1 MW of power, 200 kW from the helicon plasma source, 400 kW microwave power, and 400 kW radio frequency heating. A primary goal of MPEX is to examine the impact of high-fluence plasmas on prototypic materials.  This will involve mounting samples of these materials, which may be neutron irradiated, on an actively cooled target and exposing to high density, high heat-flux plasmas for durations of up to 10⁶ seconds. Several in-vessel components (IVCs) are crucial to the capture of heat from the various plasma heating sources.

MPEX should be one of a generation of fusion devices, culminating in a Fusion Pilot Plant (FPP), that must handle heat heat-fluxes in steady-state.  Novel manufacturing, engineering, and simulation methods will be necessary to develop feasible technology for the plasma facing components in an FPP.  This is emphasized in the recent Community Plan: “Recognizing that it is unlikely that existing materials will provide adequate PFC system performance, it is imperative to initiate and sustain a program for the development of new, innovative solid materials that will form the basis of the solid first wall armor, solid divertor targets and the liquid metal PFC substrates through techniques such as advanced manufacturing, nano-engineered materials, material by design, virtual engineering” [3].  This presentation will consider innovations in topology optimization and advanced manufacturing that should enable the development of novel plasma facing components that surpass the performance of the current state-of-the-art.

[1] Juergen Rapp, et al, Fusion Sci. Technol., 64, 237 (2013)

[2] Juergen Rapp, et al, Fusion Eng. Des., 156, 111586 (2020)

[3] Report of the 2019-2020 APS DPP Community Planning Process, A Community Plan for Fusion Energy and Discovery Plasma Sciences, https://drive.google.com/file/d/1w0TKL_Jn0tKUBgUc8RC1s5fIOViH5pRK/view, pg. 53, 2020.

Bio: Dr. Lumsdaine is Group Leader for the Fusion Engineering Group at Oak Ridge National Laboratory in the Fusion Energy Division. He also serves as Lead Engineer for the Materials Plasma Exposure eXperiment (MPEX) facility – a linear plasma-material interaction device planned for future operation at ORNL. Dr. Lumsdaine received his Ph.D. in Mechanical Engineering from the University of Michigan.  He has served as an Associate Professor at the University of Tennessee, an Assistant Professor at the University of Texas-Pan American in Edinburg, Texas, and was the Research and Development Manager for the Nanomechanics Operations of Agilent Technologies and MTS Nano Instruments. He has over 90 publications in the fields of fusion technology, nanomechanics, smart structures, design optimization and vibration damping.  Dr. Lumsdaine chaired the Fusion Energy Division of the American Nuclear Society from 2016-19 and co-chaired the FESAC Subcommittee on Transformative Enabling Capabilities from 2017-18.