Senior Mechanical Engineer

LLNL and Pacific Fusion achieve 3,000-shot milestone with Sirius pulsed-power prototype. Lawrence Livermore National Laboratory and Pacific Fusion leaders and researchers pose by the Sirius pulsed-power prototype on May 15 to mark the system's 3,000-shot milestone at LLNL. (Photo: Garry McLeod/LLNL) Researchers from Lawrence Livermore National Laboratory and Pacific Fusion have surpassed 3,000 "shots" with Sirius, a four-stage prototype impedance-matched Marx generator (IMG) of the type that can provide pulsed power to an inertial confinement fusion machine. The team characterized this achievement as a "key milestone in the development of high-gain fusion and a practical example of government-industry partnership at work." Sirius was designed and built at LLNL and uses the same core IMG technology that San Francisco area-based Pacific Fusion is scaling for its pulser-driven inertial fusion system. The lab and the company are working under a Cooperative Research and Development Agreement (CRADA). Pulsed-power basics: In a pulsed-power accelerator, low-power electrical energy from a wall plug is stored briefly in a bank of capacitors before being released as a compressed, enormous burst (or shot) of power. The duration of the pulse is increasingly shortened until it is just billionths of a second long. With each shortening of the pulse, the released power increases. This pulser technology is relevant for fusion energy because the bursts can be used to create the extreme conditions needed to compress fuel and trigger energy-releasing fusion reactions. The pulser technology can also be used to create extreme states of matter for high-energy-density science experiments that have applications with radioisotope production, materials testing, national security, and other areas. Pacific Fusion is developing a modular pulser platform with a pulsed magnetic fusion approach to produce electricity and for stockpile stewardship. The innovation: Pacific Fusion's design uses IMG technology invented by LLNL researcher Bill Stygar and Pacific Fusion cofounder and chief technology officer Keith LeChien. This IMG is designed to deliver a faster, more efficient electrical pulse than conventional Marx generators by charging capacitors in parallel and then discharging them in a single step through carefully timed stages. In Sirius, each 100-nanosecond pulse can deliver 60 GW to a resistive load with 95 percent energy efficiency. The 3,000-shot achievement for Sirius is seen as a key step in advancing the pulsed-power accelerator prototype from the Department of Energy's Technology Readiness Level (TRL) 4 toward TRL 5, a benchmark for system demonstrations in laboratory test environments. In addition, the data that are being collected during Sirius testing will help document the reliability and lifetime performance information that is needed to guide future scale-up. Stygar explained, "For a future IMG-powered accelerator concept, reliability is a key requirement. Such systems could need components capable of operating over long service lives, potentially at up to 100 shots per year for 30 years. We needed to show that our components could last 3,000 shots and that their reliability was high enough for a next-generation machine." Close collaboration: LeChien observed, "This milestone shows what close collaboration between national laboratories and private industry can accomplish. The CRADA gives Pacific Fusion and LLNL a shared testbed for refining components, validating models, and understanding how IMG systems perform under repeated operation. Pacific Fusion is rapidly building an IMG module for our high-yield fusion system that is roughly 40 times larger in parallel, advancing IMG technology for energy and national security applications."

Pacific Fusion's latest prototype packs 440 gigawatts into an 80-nanosecond burst. 3 3 minutes read Pacific Fusion took the wraps off its latest pulser module prototype on Tuesday, a piece of equipment that allows the company to move ahead with its demonstration fusion power plant. Construction on the fusion power plant is expected to begin this summer. Results from the shipping container-sized prototype were good enough to unlock another tranche of Pacific Fusion's Series A round, which exceeds $1 billion, the company exclusively told TechCrunch. The company did not disclose the size of the tranche. Pacific Fusion is among the best-funded fusion startups. The tranche-based model is more widely used in biotech, where it saves startups time on fundraising, allowing them to remain focused on hitting technical milestones. The funding arrangement has allowed the company "to keep our heads down," Pacific Fusion CTO Keith LeChien told TechCrunch. "It means that we can lean into the future without spending 20% to 50% time constantly looking for the next piece of capital." Pacific Fusion is pursuing a form of fusion power known as inertial confinement. Its reactor will use 156 pulser modules to deliver an enormous jolt of electricity to a small fuel target in the fusion chamber. That electrical pulse will create a magnetic field around the eraser-sized fuel pellet, squeezing it until atoms inside fuse and release enormous amounts of energy. The startup's next challenge will be to scale up from the sub-scale prototype to a full-size pulser module, the core component of the demonstration power plant. The company hopes that power plant will be able to produce more electricity than the facility requires to operate, a feat no one has achieved yet. But because the race for fusion power is heating up, the company isn't waiting for results from a full-scale pulser module before starting work on the demonstration power plant. "The shovels go in the ground for that facility this summer," LeChien said. To date, inertial confinement is the only way humans have been able to produce a controlled fusion reaction that releases more energy than was required to start it, a milestone known as scientific breakeven. And so far, only one experiment, at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, has been able to produce and replicate those results. But where NIF relies on large, expensive lasers, Pacific Fusion is hoping it only needs thousands of less costly electrical switches and capacitors. Those capacitors and switches will be coordinated to generate enormous, precisely timed pulses of electricity - each about 100 nanoseconds long. Pacific Fusion's challenge is ensuring the capacitors can release their energy at precisely the right moment. If they don't, the fuel pellet won't be hit with sufficient energy to compress quickly enough to spark a fusion reaction. The company's demonstration device will have 156 full-size pulser modules. Each module will contain 32 circular stages, and each stage will be ringed with 10 bricks. One brick contains two capacitors to store power and one switch to release it. The prototype pulser module that the company recently tested is about a third the size of the full module. It contains nine stages and 90 bricks, and it released 440 gigawatts of peak power in just 80 nanoseconds. "It meets all our requirements for scaling up to build our big demonstration system," LeChien said. Once Pacific Fusion has its demonstration power plant ready, it intends to skip past scientific breakeven and go straight for facility breakeven, in which its demonstration device generates enough energy to power the entire facility. "Any fusion approach, regardless of your specific technology, has to traverse through that," LeChien said. "It's the next tectonic milestone in fusion." When you purchase through links in its articles, Real Hacker may earn a small commission. This doesn't affect its editorial independence.