Westinghouse eVinci Microreactor Reaches Zero-Power Criticality Milestone

Westinghouse completed zero-power criticality testing of its eVinci microreactor on August 25 at the Nevada National Security Site. The test was conducted in partnership with Los Alamos and Idaho National Laboratories at the National Criticality Experiments Research Center, a National Nuclear Security Administration facility.

Zero-power criticality marks the point at which a nuclear reactor sustains a controlled, self-supporting chain reaction. Unlike full-power operation, this milestone validates core design assumptions and computational models without generating heat or electricity. The achievement demonstrates progress in Westinghouse's development pathway for the containerized microreactor system.

Technology Specifications

The eVinci is a heat pipe-cooled microreactor designed to produce up to 5 megawatts electric with a 15 megawatt thermal core. The reactor uses TRISO fuel and is engineered to operate for eight or more years at full power before requiring refueling.

The factory-built and assembled design enables containerized shipping, supporting deployment across diverse applications including defense and space missions. This modular approach addresses supply chain efficiency by consolidating manufacturing and reducing on-site assembly requirements.

Development Approach

Westinghouse characterized the criticality test as part of its rapid product development philosophy, which integrates testing, modeling, simulation, and iterative design refinement. The company stated this integrated approach accelerates technology maturation while reducing technical risk.

The milestone reflects collaboration with the U.S. Department of Energy and national laboratory partners. Westinghouse Chief Technology Officer Lou Martinez Sancho noted the achievement represents the company's commitment to advancing next-generation nuclear technology.

Inertia and LLNL Cut Fusion Target Fuel Production Time

Inertia Enterprises and Lawrence Livermore National Laboratory have jointly developed an accelerated manufacturing process for the deuterium-tritium ice layer used in inertial confinement fusion target capsules. The process compresses production time from multiple days to a matter of hours, according to Inertia.

The fuel layer—a thin cryogenically frozen coating of deuterium-tritium (D-T)—is a critical component in the spherical carbon-shell capsules used for fusion ignition. Achieving a sufficiently smooth ice layer is essential for target performance. The new process improves manufacturing efficiency while maintaining the surface quality required for ignition conditions.

Supply Chain and Operational Benefits

The manufacturing acceleration delivers multiple advantages across the fusion fuel supply chain. Reduced production time directly lowers manufacturing costs per target, improving economics for pilot-plant operations. The faster cycle also decreases the quantity of tritium that must be maintained in inventory at production facilities.

Lower tritium inventory requirements reduce material handling costs and associated regulatory compliance burdens. Tritium, a scarce and tightly controlled isotope, represents both a supply constraint and a regulatory liability. Minimizing on-site quantities eases operational complexity and reduces dependence on limited fuel supplies, strengthening supply security for fusion energy development.

Myanmar SMR Site Work Could Begin in 2027

Site work for a small modular reactor (SMR) project in Myanmar could begin in 2027. This development follows an intergovernmental agreement and the establishment of a comprehensive contractual framework for the project. The Director General of Rosatom, Alexei Likhachev, indicated that entering the site signifies the start of construction.

An intergovernmental agreement, signed in March 2025 during a state visit to Russia, outlined cooperation for a 110 MW project in Myanmar. This initial phase will feature two SMRs, with the possibility of expanding the capacity to 330 MW with additional units. The SMRs planned for the project are RITM-200N pressurized water reactors, each with a capacity of 55 MW. These reactors are adapted from the RITM-200 type, which is currently utilized in the nuclear icebreaker fleet.

Russian Prime Minister Mikhail Mishustin commented on the project's potential after discussions with Myanmar President Min Aung Hlaing during an official visit to Russia. Mishustin expressed confidence that the project would significantly boost cooperation in related fields, including fundamental and applied scientific research, and would symbolize the friendship between Russia and Myanmar.

Russia is actively pursuing SMR technology, with a land-based SMR currently under construction and a sea-based unit already operational. The country views SMRs as having considerable export potential. Earlier this year, a ceremony marked the pouring of concrete for the first of two Russian SMR units in Uzbekistan, further demonstrating Russia's commitment to exporting this technology.