One of the most pressing challenges in the realm of fusion energy is determining how to initiate a fusion reaction without incurring costs that exceed the potential selling price of the generated power.
Many organizations are exploring solutions, but a definitive breakthrough remains elusive. For instance, Commonwealth Fusion Systems is investing hundreds of millions of dollars in a large reactor, although it won't be operational until next year, leaving many questions unresolved.
In contrast, newer companies are optimistic about developing fusion power plants at a lower cost. Among them, Pacific Fusion has recently shared promising findings from experiments conducted at Sandia National Laboratory, which could help reduce certain expensive components of their approach.
Fusion energy holds the potential to provide a continuous and substantial electricity supply, compatible with existing grid structures. Most startups in the fusion sector are aiming for their first commercial plants to be operational by the early to mid-2030s.
Pacific Fusion is pursuing a technique known as pulser-driven inertial confinement fusion (ICF), which shares similarities with experiments conducted at the National Ignition Facility (NIF). Their method involves compressing small fuel pellets rapidly, causing atomic fusion and energy release.
Unlike NIF's laser-based compression, Pacific Fusion plans to utilize powerful electrical pulses. These pulses will generate a magnetic field around the fuel pellet, which is roughly the size of a pencil eraser, compressing it in under 100 billionths of a second.
"The quicker you can implode it, the hotter it becomes," explained Keith LeChien, co-founder and CTO of Pacific Fusion.
Traditionally, pulser-driven ICF requires an initial energy boost to achieve the necessary conditions for fusion. Researchers have relied on lasers and magnets to preheat the fuel pellet, consuming about 5% to 10% of the total energy needed.
However, these additional elements complicate the system, increasing both costs and maintenance, thus hindering competitive pricing for the generated power.
In their Sandia experiments, Pacific Fusion modified the design of the cylinder surrounding the fuel pellet and adjusted the electrical current. They allowed some magnetic field to seep into the fuel prior to compression, effectively warming it up.
"We can make subtle adjustments in the manufacturing of this cylinder to enable the magnetic field to infiltrate the fuel before compression," LeChien noted.
The fuel is encased in plastic wrapped in aluminum. By altering the aluminum's thickness, the company can control how much magnetic field reaches the fuel. The precision required for this casing is comparable to that of a .22 caliber bullet casing, a process refined over the past century.
The modifications do not significantly alter the energy required for the target. "It takes very little energy to allow the magnetic field into the fuel's center," LeChien emphasized. "It's a minuscule fraction, significantly less than 1% of the total energy in the system."
By eliminating the magnetic system, Pacific Fusion could simplify maintenance and reduce costs modestly. However, removing the laser system could lead to substantial savings, as the scale of laser technology needed for preheating can exceed $100 million.
LeChien also pointed out that experiments like these are crucial for refining the company's simulations, ensuring they align with real-world outcomes. "Many have simulated processes and claimed they would work, but it's a different challenge to build, test, and achieve successful results," he concluded.