Helion hits 150 million °C and runs first private tritium test as it accelerates toward commercial fusion

Helion Energy announced two interrelated achievements from experiments on its Polaris pulsed, magnetically driven compression device: attaining plasma temperatures of roughly 150 million degrees Celsius and executing the first privately run test that mixed tritium with deuterium. That temperature exceeded the company’s earlier peaks and supplied diagnostic data the team says will help validate instruments and simulation models. Running tritium provided engineers with practical experience moving and controlling a radioactive fuel stream through plant systems, an operational test the company says will inform design choices for its planned deuterium–helium-3 commercial mix. Company officials and external reviewers characterize the outcomes as constructive but preliminary: hotter, denser and longer-lived plasmas, plus transparent energy accounting, are still required to approach net electrical output. The announcement arrives amid a broader uptick in private-sector activity: Avalanche Energy disclosed a $29 million financing round led by RA Capital that the startup says will fund next-generation compact devices and purchase specialized gear such as superconducting magnets. Avalanche’s round, which brings its total financing (including government grants) to about $105 million, is tied to development of FusionWERX, a shared R&D and testing campus in Richland, Washington backed by $10 million in state matching funds and expected to open in 2027. The emergence of shared testbeds and additional capital could ease access to specialized components, expand materials and tritium-handling experience across firms, and shorten hardware testing cycles. Helion is simultaneously building a commercial site in eastern Washington and says it intends to commission within the decade — an ambitious timetable observers remain skeptical of without sustained, repeatable gains. Independent reviewers from government and academia who have seen Helion’s diagnostics called the results encouraging but noted a need for peer-reviewed disclosure and reproducibility checks. Together, the physics milestone and the operational tritium campaign reduce discrete technical and regulatory uncertainties, while industry funding and shared infrastructure investments address complementary supply-chain and testing bottlenecks. However, significant technical gaps — confinement time, efficiency, materials endurance, and transition from pulsed experiments to frequent power cycles — persist and will determine whether these episodic advances translate into commercial fusion deployments.