Part 2 of 2 Parts (Please read Part 1 first)

LeChien explained, “The IMG was inspired by the need for a more practical, efficient, and reliable architecture for commercial fusion. As with a traditional Marx generator, it charges capacitors in parallel and discharges them in series. In this case, its triggering matches the speed of electromagnetic waves, so energy is delivered with about 90 percent efficiency. This boosts performance while cutting the size of the fusion system in half. The IMG uses lower-voltage components and standard materials, making it safer, easier to assemble, and more cost effective. The goal was to improve fusion performance while keeping the system simple, scalable, and practical for real-world power use.”

Each pulser module consists of stages (thirty-two for the demonstration system) connected in a series along a pulse tube. Each of the circular stages features multiple ‘bricks’ (ten per stage for the demonstration system) positioned around the circumference of the stage. Each brick consists of two capacitors and a switch. The electricity stored in the capacitors is released in pulses that travel through metallic pulse tubes toward the fusion chamber. The energy from multiple modules is funneled into two electrodes, which drive current through the target and electromagnetically compress it to trigger fusion.

Each pulser module has a diameter of about six feet and can deliver about two terawatts of peak power in a single fast pulse. PF expects its demonstration system to store about eighty megajoules of electrical energy and deliver more than sixty megaamperes in about one hundred nanoseconds.

That energy is directed to centimeter-scale deuterium-tritium fuel capsules. This is similar to laser-driven inertial confinement fusion, but this system has the ability to ‘magnetically squeeze’ the fuel inside a meter-scale fusion chamber surrounded by a deionized water tank for neutron shielding. PF’s founders believe their approach can expand the range of pressure and confinement time conditions under which fusion can be achieved.

The total footprint of the planned demonstration system is about two hundred and forty feet by two hundred and sixty feet. LeChien added that for a hypothetical future power plant, “We can tailor power plant size and capacity across a wide range, primarily by varying the designed target yield and/or repetition rate. One interesting combination would let us produce about two hundred and fifty megawatts with a very compact footprint of twenty-five acres or less.”

PF published a technical paper earlier this month on arXiv that details the company’s case for “affordable, manageable, practical, and scalable (AMPS) high-yield and high-gain inertial fusion.”

LeChien said that PF’s goal is “to generate the world’s lowest-cost firm power” and he noted that the company’s modular technology is “amenable to low-cost mass manufacturing with highly scalable supply chains. We combine estimates from detailed quote-informed costs of our demonstration system with average cost estimates of other fusion-related systems—the blanket, for example—and balance of plant.”

It requires a great deal of money to design affordable, scalable power sources. For PF, that includes the nine hundred million dollars of committed capital from investors, including venture capital firm General Catalyst, that was announced when PF emerged from ‘stealth mode’ in October of 2024. Those nine hundred million dollars are being released in tranches as the company reaches milestones.

LeChien added, “We’re pursuing federal funding opportunities to support our research, development, and demonstration efforts. Public-private partnerships are essential to accelerating fusion energy and building U.S. leadership in this field.”

LeChien continued, “About half of our technical team comes from the U.S. national labs, bringing deep fusion expertise. As we grow, we’re combining that foundation with talent from a wide range of fast-moving hard technology industries like aerospace and automotive. Our focus is on building a team that can move quickly, scale systems, and deliver real-world energy solutions.”

General Atomics

Part 1 of 2 Parts

Pacific Fusion (PF) and General Atomics (GA) recently announced plans to test Pacific Fusion’s pulser-driven inertial fusion energy concept, with commercial fusion power as the goal.

Keith LeChien is the PF cofounder and chief technology officer. He said, “We are building a fusion machine and testing all equipment—including components and a pulser module—at our PF test center. GA’s engineering expertise remains an important part of our progress, and we expect this collaboration to continue through future phases of development.”

Pacific Fusion is based in the Bay Area city of Fremont, Calif., where testing during last winter demonstrated that components of its pulser modules met performance and reliability expectations. Now, the company plans to test a production-scale pulser module designed to store electrical energy in a series of staged capacitors and deliver it in precisely controlled bursts. They will build one hundred and fifty-six such modules into a demonstration system by 2030. PF said earlier this month that it expects the machine to achieve net facility gain, generating more fusion energy out than all energy stored in the system.

LeChien explained, “Pacific Fusion is leading in pulsed magnetic fusion system design, including target physics, pulsed power, and mechanical engineering. GA has supported PF since our founding, contributing valuable engineering expertise. Their role has included system mechanical engineering analysis, benchtop prototype testing, and some infrastructure planning.”

Anantha Krishnan is the senior vice president of the General Atomics Energy Group. He said that GA’s expertise in computational modeling design, fusion science, and engineering “offers a powerful launchpad for fast-moving start-ups like Pacific Fusion.” Now that PF is progressing to module construction, GA’s role has expanded to include collaboration on full-scale fusion power plant components including system operations, cryogenics, manufacturing at production scale, and target fabrication.

GA is located in San Diego, about four hundred and fifty miles south of the PF headquarters in Fremont, California. GA has operated the DIII-D magnetic fusion tokamak there as a Department of Energy (DoE) user facility since 1986 and worked on DIII-D’s precursors since the 1950s. GA’s fusion expertise includes supplying components for ITER and manufacturing inertial fusion targets for the laser-driven National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). It also shared its own magnetic tokamak fusion pilot plant design in 2022.

Krishnan said, “General Atomics has developed significant capabilities in fusion science and technology over several decades of research and development. We are now applying these capabilities to help fusion energy companies tackle some of the toughest scientific and engineering challenges in achieving the goal of commercial fusion energy.”

Krishnan added, “GA’s business model is to provide our unique technical expertise and capabilities to enable our collaborators in the fusion energy industry to successfully bring fusion energy to the market. We work closely with a wide range of collaborators across the fusion landscape, including those focused on magnetic as well as inertial fusion.” LeChien is also the coinventor of the impedance-matched Marx generator (IMG) that the company’s power plant concept relies on.

Please read Part 2 next

Pacific Fusion

General Matter (GM) says it will use a novel, scalable, cost-competitive technology to address a ‘commercial bottleneck’ in the U.S. nuclear fuel cycle and that it will be shipping enriched uranium by the end of the decade.

GM was one of four companies selected in October of 2024 by the U.S. Department of Energy (DoE) to provide enrichment services to help establish a steady U.S. supply of high-assay low-enriched uranium (HALEU). According to information available at the time, the company was registered in California earlier in the year, with Scott Nolan named as its CEO. Nolan is a former SpaceX employee who is a partner at venture capital firm Founders Fund which was co-founded by billionaire investor Peter Thiel.

On the 14^th of April, the company announced itself on social media. It posted on X that “For the past year, General Matter has been incubated within Founders Fund, with a team from SpaceX, Tesla, Anduril, national labs, and the DOD. We are undertaking an engineering challenge which, if successful, will fundamentally improve the trajectory of our nation.”

Nolan said, “I spent over a year at Founders Fund searching for an American enrichment company to invest in, only to find there wasn’t one. So we built our own. General Matter is filling the US nuclear fuel gap. We are enriching uranium in America, and we will be shipping by the end of the decade”.

On the same day, Bloomberg reported that Peter Thiel is joining the board of GM. According to Bloomberg, the company has “built up a small operation in Los Angeles of roughly two dozen engineers, nuclear scientists and safety experts, pulling staff from national labs and the private sector.”

GM has not provided any details of its process for enriching uranium, but on the 2^nd of December last year, Nolan submitted a Letter of Intent to the U.S. Nuclear Regulatory Commission (NRC) in anticipation of a “forthcoming application for the necessary licenses to support the production and handling of High-Assay, Low-Enriched Uranium (HALEU)”.

The letter notes that “General Matter has been awarded an Indefinite Delivery/Indefinite Quantity (IDIQ) contract by the Department of Energy’s Office of Nuclear Energy (DOE-NE) under Solicitation No. 89243223RNE000031. This award specifically supports the DOE-NE’s strategic objectives of securing a domestic supply chain of HALEU to support the continued development of advanced reactors and to strengthen US leadership in nuclear technology. As a DOE-NE HALEU IDIQ awardee, General Matter’s anticipated scope of responsibility under future task orders includes the enrichment, storage, and transportation of HALEU. These operations are critical to meeting the growing demand for enriched uranium necessary to support both domestic and international markets, with an emphasis on maintaining safety and security standards.”

HALEU contains between five and 20 percent of fissile uranium-235 and will be required to meet the fuel needs of many of the advanced reactor designs that are currently being developed.

Information submitted to the NRC with the Letter of Intent is classed as ‘proprietary and confidential’, with the company saying, “Years of cumulative effort have gone into the work supporting this content, and given the innovative and differentiated insights generated by the work, others would need to expend great effort to duplicate the information. This information cannot be acquired elsewhere.”

General Matter

The U.S. Department of Energy (DoE) announced on April 23^rd that the Argonne National Laboratory (ANL) has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop). The upgrade is the first of its kind in the U.S. in more than thirty years, according to the DoE. The exchange will help test components and operations for the sodium-cooled fast reactors currently being developed.

Sodium-cooled fast reactors use liquid sodium as a coolant instead of water. They operate at higher temperatures and lower pressures than current commercial nuclear reactors. They achieve high power density with low coolant volume and sustain the fission chain reaction with fast neutrons. They are currently used in several countries including the US, Russia, China, and India.

More than seven hundred and fifty gallons of reactor-grade sodium flow through METL, making it the “nation’s largest liquid metal test facility,” according to the DoE. METL may not hold that record for long, however. TerraPower is a sodium fast reactor developer with cost-shared funding under the Advanced Reactor Demonstration Program to build a grid-scale Natrium reactor. It is currently constructing a sodium test and fill facility in Kemmerer, Wyoming, which is constructed to hold four hundred thousand gallons of liquid sodium.

A cold trap like the one that was just replaced in METL is a critical component of liquid metal reactor designs. It is utilized to filter out oxide impurities present in the sodium coolant. If these impurities are not removed, they can cause accelerated corrosion of the systems and lower flow rates, degrading the reactor’s performance.

ANL replaced the component to meet specifications for future METL experiments. The facility uses welded construction techniques that the DoE says are “consistent with the maintenance of any advanced liquid metal reactor.” The replacement project builds U.S. experience in working with and replacing sodium loop components.

The sodium in the cold trap was frozen before the cold trap was removed from the system and a new one was welded onto the sodium piping in its place. After months of planning, the process was accomplished in two weeks. During the replacement process, the rest of the sodium in the test loop remained molten and in operation, according to the DoE.

Matthew Weathered is a principal nuclear engineer at ANL. “It’s exciting. The METL team is revitalizing and developing these key operations and maintenance techniques to ensure we are able to deploy U.S. sodium cooled reactors in the near future.”

METL was developed in 2018 to help advance research on liquid metal technologies and to test components for potential use in sodium fast reactors. The facility can reach an operating temperature of six hundred and fifty degree Fahrenheit. This is within the typical sodium reactor temperature range.

Reactor developers who are working with Argonne’s team at METL include ARC Clean Energy, Oklo, and TerraPower. METL plans to expand its testing capabilities in 2026 with the installation fifth test vessel.

The cold trap replacement project was funded through the DoE’s National Reactor Innovation Center (NRIC), which funds operations and maintenance activities at the METL facility. ANL consulted with the French Alternative Energies and Atomic Energy Commission before performing the replacement operation.

Argonne National Laboratory