Space reactor developer Antares secures BWXT uranium fuel agreement

(SpaceEnergy) US nuclear developer Antares has signed a multi-year uranium fuel agreement with BWX Technologies (BWXT), strengthening the supply chain for its compact fission reactors, including technology supporting its space nuclear power programme.

Antares announced on 27 October that BWXT would manufacture tri-structural isotropic (TRISO) fuel from high-assay low-enriched uranium (HALEU) at its Lynchburg, Virginia, facility.

The agreement provides an initial allocation of one metric tonne of uranium, with provision to increase quantities as reactor deployment requirements develop.

BWXT said deliveries would be governed by subsequent task orders specifying quantities, schedules and technical requirements.

The manufacturing line previously produced fuel for Antares' Mark-0 demonstration reactor, which achieved initial criticality in June 2026.

“We achieved criticality with BWXT fuel, and it's what will power our electricity-producing reactor, Mark-1, in 2027,” said Antares chief executive Jordan Bramble.

The agreement establishes a second qualified TRISO fabrication source for Antares, following a separate arrangement with Standard Nuclear announced in August.

In September, Antares secured a US$161 million US Air Force Strategic Breakthrough award to advance nuclear power for space applications.

That programme includes a ground demonstration of its R1-S reactor and integration with a spacecraft towards flight certification.

Antares also intends to use Mark-1 to power an operational ground-to-space asset under the programme.

The new BWXT agreement does not specify a fuel allocation for the R1-S spacecraft or establish a spaceflight delivery timetable.

Neither company disclosed the agreement's financial value.