The central question for fusion power remains unanswered: how do you ensure the cost to start the fusion reaction is not higher than the price at which you can sell the resulting electricity? Many have ideas, but no one has solved it yet. For example, Commonwealth Fusion Systems is building a massive reactor costing several hundred million dollars, but that device will not be turned on until next year, leaving the economic question open.
Other, more recently founded companies believe they can build a fusion power plant for less. Pacific Fusion is one such company, and it recently announced the results of experiments performed at Sandia National Laboratory. The company says these experiments will eliminate some costly components from its design.
Fusion power promises to generate large amounts of electricity continuously and deliver it in a way familiar to today’s grid operators. Most fusion startups are targeting the early to mid-2030s to activate their first commercial power plants.
Pacific Fusion is pursuing an approach known as pulser-driven inertial confinement fusion. At its core, it is similar to experiments carried out at the National Ignition Facility. The company compresses small fuel pellets in rapid succession, causing atoms inside to fuse and release energy. However, where the National Ignition Facility uses lasers to begin the compression, Pacific Fusion intends to use massive pulses of electricity. These pulses create a magnetic field that encircles the fuel pellet, which is about the size of a pencil eraser, causing it to compress in less than 100 billionths of a second. The faster the implosion, the hotter the fuel becomes.
One challenge with pulser-driven inertial confinement fusion is that the process has typically required a kickstart to work properly. To create conditions hot enough for fusion, researchers have used both lasers and magnets to preheat the fuel pellet. This added energy, while a small percentage of the total, introduces upfront complexity, cost, and maintenance requirements, making it harder to sell power at competitive prices.
In its Sandia experiments, Pacific Fusion tweaked the design of the cylinder encasing the fuel pellet and adjusted the electrical current. Before the main pulse that ignites fusion, the company allowed a small amount of the magnetic field to leak through to the fuel, warming it beforehand. By varying the thickness of the aluminum wrapping around the plastic fuel target, the company can control how much magnetic field reaches the fuel. This manufacturing requirement is precise but comparable to what is needed for a .22 caliber bullet casing, a process perfected over more than a century.
These tweaks do not significantly change the total energy delivered to the target. The energy required to allow the magnetic field in is a tiny, effectively unnoticeable fraction of the overall system energy. Eliminating the separate magnetic preheating system would simplify maintenance and modestly reduce costs. However, removing the need for a preheating laser would cut costs significantly, as such a laser system can cost over one hundred million dollars.
Experiments like these also help refine the company’s simulations, ensuring they match real-world results. Closing the loop between simulation, construction, testing, and successful operation is a difficult but crucial step.