Athena is Xcimer Energy's planned first laser inertial fusion power plant, designed to deliver 400 MW to the grid with a molten-salt wall chamber at up to 1 Hz. DOE approved its preconceptual design in June 2026; Xcimer targets 2035, after the Vulcan wall-plug breakeven demonstrator planned for 2031.
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Current state
| Status | Concept |
| Country | United States |
| Developer | Xcimer Energy |
| Developer type | Private |
| Concept | Laser inertial |
| Fuel | D-T |
| Purpose | Commercial plant |
| Net energy target | 2031 |
| Grid power target | 2035 |
| Target output (MWe) | 400 |
| Site | Site not yet determined |
| Private funding raised | USD 200m (as of 2026-06) |
| Public funding | DOE Milestone-Based Fusion Development Program awardee |
Notes
net energy target 2031 refers to the separate Vulcan device targeting engineering (wall-plug) breakeven (Q_eng-type), not Athena itself.
Timeline
- 2025-02-17 — Xcimer was awarded $4 million in federal funding to improve the efficiency of its inertial fusion lasers. (source)
- 2026-06-10 — DOE approved Xcimer's preconceptual Athena power plant design under the Milestone program. (source)
- 2026-09-10 — RTX announced an investment in and partnership with Xcimer on directed-energy laser technology. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
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About Xcimer Energy
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Sources
- DOE approves Xcimer laser fusion power plant design — ANS Nuclear Newswire, checked 2026-10-11
- FAQ — Xcimer Energy (primary), checked 2026-10-11
- Xcimer Energy homepage (news) — Xcimer Energy (primary), checked 2026-10-11