The NOVA release is the most specific company-published technical description found. It says NOVA used the same fuel, moderator and reactivity-control scheme as Ward 250 (HALEU TRISO fuel, graphite moderator, boron-carbide control elements in stainless steel), and that its data would inform helium-loop operations and temperature ramp-up for Ward 250. It credits the core test geometry to LANL's earlier Deimos critical assembly (2024), and quotes Valar's lead core designer, Sonat Sen, saying the data would validate Valar's proprietary design software. DOE defines HALEU as uranium enriched between 5% and less than 20% U-235 (today's reactors use fuel up to 5%); the release does not give Valar's exact enrichment.

• Los Alamos National Laboratory and Valar Atomics Announce Project NOVA Criticality Milestone in Nevada (Valar Atomics (joint announcement with LANL), 2025-11-18) primary company “NOVA uses the same fuel, moderator, and reactivity-control scheme as Ward250”
• What is High-Assay Low-Enriched Uranium (HALEU)? (U.S. Department of Energy, Office of Nuclear Energy, 2024-12-03) primary government “By definition, HALEU is enriched between 5% and less than 20%”