DARWIN stands for Dispatchable Adaptive Reactor With Interchangeable compoNents. Each word in the name reflects a core design principle of the project.

Dispatchable means the reactor can adjust its power output across the full range, from 0 to 100 percent, on demand, responding in real time to changing energy needs rather than operating at a fixed output like conventional plants.

Adaptive means the system is not locked into a single purpose or configuration. A DARWIN reactor can be reconfigured within days to serve entirely different functions: electricity generation today, floodwater pumping tomorrow, water desalination next month.

Reactor refers to the nuclear core at the heart of the system, the primary module that generates heat, pressure, and radiation as its fundamental outputs, which are then directed through interchangeable secondary modules toward specific applications.

With Interchangeable Components captures the defining architectural innovation: both the reactor core assemblies, comprising fuel, reflector, and control elements, and the secondary application modules can be swapped out, allowing the same platform to serve radically different use cases without rebuilding from scratch.

Together, these principles describe a reactor that evolves with society’s needs, and stands in sharp contrast to today’s century-long, single-purpose nuclear installations.

The DARWIN initiative seeks to redefine how nuclear energy can serve society in the age of climate change. Traditional nuclear power plants were designed for a different era: static, century-long operation delivering only electricity to established urban grids. As extreme weather events, infrastructure failures, and mass climate migrations become more frequent, the world urgently requires energy systems that are mobile, flexible, and highly adaptive.

Nuclear energy stands out among low-carbon options for its unique ability to provide continuous, high-density power regardless of weather or time of day. Reaffirmed at COP28, nuclear energy is now recognised globally as an essential pillar of the transition to a low-carbon future. However, existing plant designs have their roots in 1950s use cases, optimised for base-load electricity delivered to growing urban grids, with little adaptability to the very different challenges of the 2030s and 2040s.

DARWIN’s primary goal is to pioneer a new generation of Small Modular Reactors (SMRs) that can deliver not only electricity, but also direct heat, cooling, mechanical energy for pumping and purification, hydrogen production, and medical isotope generation. By developing modular and reconfigurable systems, the project establishes the scientific foundation for reactors that can quickly adapt to diverse and unforeseen challenges, from emergency flood response to water desalination in drought-stricken regions.

The project’s first phase focuses on conceptual research and the scientific design principles for a variable, reconfigurable reactor platform. Rather than moving straight to engineering, DARWIN begins with a rigorous exploration of fundamental challenges, seeking to understand what future use cases demand and what physics and simulation must deliver to meet them. The detailed objectives are as follows.:

• Investigate Use Cases – The team will identify limiting parameters including reactor power, operational temperature, power peaking factors, and reactivity coefficients for each critical use case: disaster response, desalination, district heating, hydrogen production, and off-grid power generation.

• Develop Conceptual Designs – Conceptual designs of individual reactor modules will be prepared, each tailored to specific needs, with the goal of maximising the versatility of the DARWIN platform and ensuring its applicability across a wide range of present and future applications.

• Optimise core performance – State-of-the-art simulation tools will be deployed, including Monte Carlo particle transport, computational fluid dynamics, and machine learning algorithms, to optimise reactor design quantities such as criticality, control, cooling, and radioactive inventory management. As DARWIN is the first project of its kind, new codes and methodologies beyond the current state of the art will also be developed and tested.

• Open Roadmap – The team will publish a transparent development path enabling research physicists, nuclear engineers, civil engineers, policymakers, and industry partners worldwide to understand goals, benefits, and pathways for engagement, ensuring the ideas take root across the broader energy development community.

Through these objectives, DARWIN establishes the groundwork for long-term innovation in nuclear technology.

The urgency of DARWIN arises from changing energy demands in an increasingly climate-stressed world. Severe floods, record heatwaves, prolonged droughts, and cascading infrastructure failures all demand reliable, mobile power sources that conventional systems simply cannot provide.

Slovenia’s devastating 2023 floods, the largest natural disaster in the country’s recorded history with an estimated 7 billion euro cost of recovery, offer a vivid illustration of the scale of disruption that is becoming more common. As warming accelerates, scenarios such as real-time emergency pumping of an entire city’s floodwater, spot cooling in urban areas routinely exceeding 50 degrees Celsius, or rapid large-scale water desalination during severe droughts will require enormous and flexible energy resources that existing infrastructure cannot deliver.

Existing nuclear plants are immobile, take a decade or more to build, and are optimised exclusively for electricity generation, leaving a major gap in society’s ability to respond to emergencies and sustain critical services in off-grid or infrastructure-compromised settings. Current SMR designs, while an improvement, still share the same fundamental limitation: a fixed output profile aimed at delivering electricity to functioning grid systems.

DARWIN addresses this gap by offering dispatchable, multi-functional, and mobile nuclear energy systems. These reactors can move where they are needed, scale output from 0 to 100 percent on demand, and switch between functions: from pumping floodwater to generating clean hydrogen to supplying industrial process heat, all from the same underlying system, reconfigured within days as needs evolve. Able to operate independently of grid infrastructure and to complement intermittent renewable sources such as solar and wind, DARWIN is designed to be a cornerstone of resilient, low-carbon energy infrastructure for the decades ahead.