TerraPower Isotopes (Actinium-225)
Overview
Medical-isotope business producing actinium-225 (Ac-225), a rare alpha-particle-emitting isotope used in targeted radiotherapeutics for cancers including prostate, breast, colon, and neuroendocrine cancers, melanoma, and lymphoma.
Producing Ac-225 at commercial scale via weekly production runs since October 2024, supplying pharmaceutical partners for radiopharmaceutical development and human clinical trials from its Everett, Washington facility. A second, larger cGMP facility (the Bellwether Laboratory in Philadelphia, $450M investment, 250,000 sq ft) broke ground May 6, 2026 and is intended to expand global Ac-225 capacity twentyfold, with production starting in 2029. TerraPower Isotopes sources its thorium-229 feedstock from DOE contractor Isotek Systems at Oak Ridge; a new Isotek analytical lab opened August 21, 2026 speeds Th-229 delivery and supports the decay-based technique TerraPower uses to extract Ac-225.