The U.S. Department of Energy has approved the Documented Safety Analysis (DSA) for Oklo Inc.’s Groves Isotope Test Reactor, located in Lockhart, Texas. With this clearance, the project enters its final pre-startup review phase and is targeting first criticality by July 2026. It is the first advanced reactor on private land — with fuel and systems sourced entirely from commercial suppliers — to reach this milestone under the DOE’s Reactor Pilot Program.
The DSA is the document that establishes the facility’s definitive safety basis: it covers hazard analysis, operational requirements, and the safety controls needed to start the reactor. It follows the earlier approval of the Preliminary Documented Safety Analysis (PDSA), which set the safety foundation during the design and construction phase. With both documents now approved, two steps remain: a DOE readiness review and formal startup authorization. Only then will the facility be allowed to receive nuclear fuel, conduct startup testing, and advance toward first criticality — the point at which the reactor achieves and sustains a controlled, self-sustaining chain reaction.
On the technical side, Groves is an open-pool, light-water-cooled, non-pressurized 15 MWt reactor. The core sits at the bottom of a deep water tank, which serves as both a radiation shield and a heat sink, eliminating the pressure vessels typical of commercial power plants. The design is based on the VIPR system — Versatile Isotope Production Reactor — geometrically optimized to generate high-intensity neutron fluxes for isotope production. Groves runs on standard low-enriched uranium, allowing the project to source all fuel through existing commercial supply chains. The entire construction was completed in 229 days.
The strategic context is clear. In August 2025, the DOE selected eleven advanced reactor projects for the Reactor Pilot Program, with the goal of bringing at least three reactors to first criticality by July 4, 2026. Groves is among the most advanced candidates. The project also addresses a real supply chain vulnerability: many medical and industrial isotopes are currently imported or produced in aging facilities. Oklo’s subsidiary Atomic Alchemy, acquired in 2025, will handle the processing of irradiated material at a radiochemistry laboratory in Idaho, where the NRC has already issued a license for the handling, processing, and distribution of a limited quantity of selected isotopes. That laboratory is expected to generate its first revenues this year.
If first criticality is achieved on schedule, Groves will become a concrete benchmark for how an advanced commercial reactor can be built and licensed outside national laboratories, on timelines and at costs the private market can sustain. Oklo’s operational model is designed to replicate this framework: Groves as a pilot plant to validate procedures and gather data, with lessons then applied to subsequent projects — including the Aurora Powerhouse at Idaho National Laboratory, also currently under DOE review. The logical roadmap is already laid out. Execution is now the only variable that matters.
