NANO reactor core block ready for testing

Tuesday, 25 March 2025

The 1:2 scale block has been precisely engineered to be representative of a fuel element of the ZEUS microreactor core. The initial testing phase will focus on the assessment of the thermo-mechanical performance of the block under anticipated prototypical conditions for the reactor. The results will inform the next stages of reactor development, and will be crucial for verifying engineering plans, refining physics models, and optimising core and heat management systems.

The component will be heated conventionally using linear heaters as fuel rod surrogates, NANO Nuclear Head of Nuclear Reactor Design and Materials Peter Hosemann explained: "The test will be used to verify temperature distribution, to investigate fit tolerances, and to confirm and benchmark our models, paving the way for a larger sub-core assembly."

The Zeus microreactor features a completely sealed core that relies on a highly conductive moderator matrix to dissipate the fission energy with no in-core fluid system. The reactor core and power conversion system fit within a single standard shipping container, facilitating transportation to remote sites, providing on-demand capable, clean, scalable power for data centres, remote locations, industrial sites, military operations and disaster relief scenarios, the company says.

The lack of an in-core fluid in our ZEUS design not only simplifies greatly the design but also enables rapid prototyping and non-nuclear testing, NANO Nuclear Senior Director and Head of Reactor Design Massimiliano Fratoni said, adding: "We are expecting to iterate quickly through progressively larger scale tests up to full core."

Preparations are now under way to mount insulation, fixtures, and instrumentation to create a single-block demonstration unit, which will eventually scale up to a fully functional demo core assembly, NANO said. In the next phase, the team will integrate cabling, sensors, and additional structural components to build a fully instrumented demo unit, enabling it to gather essential data on heat transfer, material performance, and overall reactor safety margins and validating the reactor's thermal and structural performance before full-scale assembly.

As well as its ZEUS and ODIN microreactor designs, NANO Nuclear is developing the KRONOS micromodular reactor and the LOKI transportable reactor, nuclear technology it acquired from Ultra Safe Nuclear Corporation at the end of 2024.

In December, NANO Nuclear signed a memorandum of understanding with the US Department of Energy Idaho Operations Office to evaluate the feasibility of siting experimental reactors at the Idaho National Laboratory.