US scientists take inspiration from nature to design next-gen nuclear fuel

Scientists at Idaho National Laboratory (INL) in the US are experimenting with a surprising source of inspiration for next-generation nuclear fuel: nature’s mathematics. Their latest research focuses on triply periodic minimal surfaces (TPMS) — intricate, repeating lattice structures that occur in butterfly wings, sea urchin shells, and even bone marrow.

According to researchers, these naturally efficient geometries in nuclear fuel design can dramatically enhance heat transfer and overall performance. The approach replaces traditional solid fuel forms with mathematically optimized structures, potentially paving the way for safer, more efficient, and futuristic reactor technology.

Nature shapes nuclear At the intersection of mathematics and nature, researchers have long observed patterns that repeat with elegance and purpose. From the spirals of sunflower seeds shaped by Fibonacci numbers to the fractal symmetry of snowflakes, these natural designs often follow mathematical rules found across scales.

One such rule concerns minimal surfaces — shapes that form the smallest possible area within a given boundary, as in the delicate film stretched across a soap bubble. Minimal surfaces also appear in nature, including in butterfly wings and sea urchin shells. Building on this concept, INL is now exploring TPMS as a blueprint for a radically new nuclear fuel geometry. Their concept, called the Intertwined Nuclear Fuel Lattice for Uprated heat eXchange (INFLUX), replaces the traditional cylindrical fuel rod with a complex, repeating TPMS lattice.

This structure increases surface contact with coolant and enables more efficient heat transfer. Unlike mid-20th-century fuel rods inspired by simple tube-based heat exchangers, TPMS designs require advanced additive manufacturing techniques that only recently became feasible.

By borrowing geometric efficiency from nature, INL researchers aim to create safer, higher-performing, and more compact nuclear fuel for future reactor systems. “We saw heat exchangers that use triply periodic minimal surfaces and said, ‘It’s just perfect. It’s nature’s answer to the optimal geometry for nuclear fuel, said Nicolas Woolstenhulme, a researcher at INL, in a statement. Future fuel forms In recent laboratory testing, INL researchers and the University of Wisconsin created a 3D-printed, electrically conductive model of the INFLUX fuel lattice to evaluate how the unusual geometry performs under heat.

The structure contained sensors and was heated using an electric current to simulate how real fuel behaves inside a reactor. The team claims their tests with both gas and liquid coolants showed that the TPMS-based fuel design transfers heat roughly three times more efficiently than standard cylindrical fuel rods, potentially significantly increasing power output and improving reactor economics.

Modeling further suggests that better heat transfer could allow thinner fuel, lower operating temperatures, and reduced thermal stress. However, manufacturing the complex, intertwined structure using nuclear-grade materials remains a major challenge.

To address this, the team developed a hybrid approach combining advanced additive manufacturing and hot-isostatic pressing, successfully fabricating both ceramic–metal and metal–metal prototypes. According to researchers, the INFLUX lattice forces coolant through a smoother but more winding path, improving heat removal and potentially offering safety advantages, especially during accident scenarios.

It may also provide neutronic benefits by reducing pathways through which neutrons can escape. Future work will focus on identifying reactor types that would benefit most, with microreactors and gas-cooled systems considered strong candidates.