DOE approves Xcimer power plant design milestone

11 June 2026

The US Department of Energy has formally approved Xcimer Energy‘s preconceptual design and technology development roadmap milestone under the DOE’s Milestone-Based Fusion Development Program for Athena, the company’s architecture for commercial power plants. Xcimer said the acceptance follows completion of earlier milestones over the programme’s first 18-month budget period. Its next phases of work include full-scale subsystem testing, engineering validation, and preparation for an integrated plant demonstration.

Athena is the reference architecture for Xcimer’s planned fleet of fusion power plants. Designed for continuous operation, it integrates the company’s excimer laser platform with target delivery, fusion chamber, tritium breeding, and power generation systems. Xcimer’s submission to the DOE ran to 724 pages, covering plant performance targets, economics, system-level engineering requirements, safety and environmental analyses, and technology development pathways. The Athena design pairs the company’s krypton fluoride excimer laser architecture with a liquid wall chamber and is designed to run continuously at repetition rates of up to 1 Hz.