Electricity Generation and Delivery

GE Research will develop a medium voltage direct current (MVDC) circuit breaker using gas discharge tubes (GDTs) with exceptionally fast response time. GDTs switch using no mechanical motion by transitioning the internal gas between its ordinary insulating state and a highly conductive plasma state. The team will develop a new cathode and control grid to reduce power loss during normal operation and meet program performance and efficiency targets.

Eaton will build an ultra-high efficiency, medium voltage direct current (MVDC), electro-mechanical/solid-state hybrid circuit breaker (HCB) that offers both low conduction losses and fast response times. The team will also develop a high-speed actuator/vacuum switch (HSVS) combined with a novel transient commutation current injector (TCCI). This switch will transfer power to a separate solid-state device, interrupting the current in the event of a fault. The design should allow for scaling in voltage and current, enabling a range of circuit breakers across the MV application space.

Drexel University is proposing a solid-state MV circuit breaker based on silicon carbide devices, a resonant topology, and capacitive wireless power transfer that aims to significantly improve breaker performance for the MVDC ecosystem. The project combines innovations in using an active resonant circuit to realize zero-current switching, wireless capacitive coupling between the conduction and breaker branches to avoid direct metal-to-metal contact for rapid response speed, and wireless powering to drive the MV switches for improved system reliability.

Marquette University will leverage the technology gap presented by the lack of DC breaker technology. The project objective is to create an industry standard DC breaker that is compact, efficient, ultra-fast, lightweight, resilient, and scalable. The proposed solution will use a novel current source to force a zero current in the main current conduction path, providing a soft transition when turning on the DC breaker. A state-of-the-art actuator that can produce significantly more force than current solutions will also be used.

A Z-pinch fusion device has an electrical current driven through the fusion fuel, creating self-generated magnetic fields that compress and heat the fuel toward fusion conditions. While a Z-pinch with no equilibrium flows has rapidly growing instabilities that disrupt the plasma within nanoseconds, the Z-pinch can be stabilized if an axial plasma flow varying strongly enough with radius is introduced.

Los Alamos National Laboratory (LANL) will lead a team that will test an innovative approach to controlled fusion energy production: plasma-jet driven magneto-inertial fusion (PJMIF). PJMIF uses a spherical array of plasma guns to produce an imploding supersonic plasma shell, or “liner,” which inertially compresses and heats a pre-injected magnetized plasma “target” in a bid to access the conditions for thermonuclear fusion. LANL will develop a magnetized target plasma for the approach at a smaller scale than would be needed for a reactor.

As fusion machines move toward a burning-plasma regime, liquid first walls and blankets may be needed to handle first‑wall heat-flux, reduce erosion, and eventually to convert energy and generate tritium fuel. Repetitively pulsed fusion designs may require extreme electrode survivability, where the electrode may be solid, liquid, or a combination of both. It is critical to address how plasma dynamics in the fusion plasma will couple with both liquid-metal and electrode-material dynamics for fusion energy to become realizable.

The University of Maryland, Baltimore County, will advance the performance of the centrifugal-mirror (CM) fusion concept, which has previously demonstrated stable plasmas with temperatures above 100 eV. The CM has a simple, axisymmetric geometry and provides a potential low-cost pathway to a breakeven experiment. The team will azimuthally rotate a mirror-shaped magnetized plasma to supersonic speeds using high-voltage biasing between a central rod and outer electrode rings.

Los Alamos National Laboratory and its partner, the University of Nevada-Reno, will provide visible spectroscopy and soft x-ray imaging diagnostics to characterize the performance of a number of lower-cost, potentially transformative fusion-energy concepts. Multi-chord visible spectroscopy measurements will enable the identification of impurities and their spatial and temporal variation in the plasmas, which is essential for understanding plasma composition and plasma conditions.

Knowing the magnetic field inside a fusion device is essential for understanding and validating performance, but measuring the magnetic field without perturbing it is exceedingly challenging. This Capability Team will build a non-perturbative, portable diagnostic to measure the topology of the equilibrium magnetic field vector in potentially transformative, magnetically confined fusion devices.