The Department of Energy’s Gateway for Accelerated Innovation in Nuclear (GAIN) has recently awarded three second-round fiscal year 2026 vouchers to support the development of advanced nuclear technologies. Each company will get access to specific capabilities and expertise in DOE’s national laboratory complex. In this round of awards both Oak Ridge National Laboratory (ORNL) and Argonne National Laboratory (ANL) will be responsible for a minimum 20% cost share, which can be an in-kind contribution. The three companies receiving awards are Constellation Energy, Nano Nuclear Energy and NuCube Energy all of which have received GAIN vouchers in the past.
Constellation Energy will collaborate with ORNL to investigate the underlying physics of moisture carryover phenomena in boiling water reactors (BWRs). The aim is to develop reduced-order predictive models that can be integrated into Constellation’s evaluation tools. Constellation and ORNL will use modelling and simulations, including ORNL’s Virtual Environment for Reactor Applications (VERA), to lower fuel cycle costs and improve capacity factors across Constellation’s BWR fleet, particularly in high power density and uprated cores. Last year, Constellation’s Dresden and Clinton BWRs had their licences renewed for 20 more years by the Nuclear Regulatory Commission (NRC).
Nano Nuclear Energy will collaborate with ORNL to demonstrate safety margins, performance reliability, and licensing readiness of its Kronos microreactor. Nano Nuclear and ORNL will quantify the impact of nuclear data, modelling assumptions, and operational parameters on key reactor physics metrics, including reactivity, power distribution, and temperature coefficients. The University of Illinois–Urbana-Champaign, in partnership with Nano Nuclear, recently submitted a construction permit application to NRC to build a Kronos microreactor.
The Kronos MMR is a stationary, high-temperature gas-cooled microreactor designed as a 45 MWt unit capable of generating approximately 15 Mwe. The reactor uses helium gas as its primary coolant and TRISO (tristructural-isotropic) fuel embedded in prismatic graphite blocks. It integrates molten salt thermal storage, allowing it to store up to 10 hours of heat to provide flexible, on-demand electricity and process heat.
NuCube Energy will collaborate with ANL to verify the autonomous operation and remote monitoring systems of its DeccaCell microreactor. NuCube and Argonne will use a digital twin of the reactor to test autonomous control architecture, and Argonne will be adapting its existing autonomous operation and diagnostics framework to demonstrate automated startup, remote monitoring, islanding-mode transitions, and predictive maintenance within a validated simulation environment. The project aims to lower operational costs, enhance safety, and enable commercialisation.
The NuCube DeccaCell is a modular, solid-state nuclear fission microreactor. It is designed to generate up to 15 MWe and can produce process heat exceeding 1,100°C. The reactor is designed for a long operational life of 7 to 30 years before requiring refuelling. It utilizes heat pipe technology and TRISO fuel. The company signed a memorandum of understanding to site and test its microreactor at the Utah San Rafael Energy Lab (USREL).
The first round of FY 2026 vouchers went to BWXT Advanced Technologies, NuScale Power, and Orbia Fluor & Energy Materials USA. The fourth round of FY 2025 vouchers went to Colorado Springs Utilities, EnergyHQ, Natura Resources, NuFuels, Oklo, TerraPower, and Zeno Power Systems. The third round of FY 2025 vouchers went to AiMiLight Sensors and Intelligent Systems, Hayward Tyler, and Standard Nuclear.
