Buried under an Indiana campus, a 10-microwave reactor from the early sixties became the only US nuclear plant with fully digital controls, and engineers adjusted its power from hundreds of miles away
The room is deep underground, beneath a university building in Indiana, humming with the low drone of a server farm.
Inside, a reactor has been running since the early sixties.
No dials. No knobs. No analog gauges of any kind.
Although some countries already operate reactors with digital controls, this is the only fully digital reactor licensed by the US Nuclear Regulatory Commission.
Instead: keyboards, computer screens, ethernet cables, the complete nervous system of a machine that is also, formally, a licensed nuclear reactor.
So how did a research machine rated at 10 microwaves of power end up rewriting what American nuclear regulators will allow?
Why every other US reactor still runs on technology from the sixties
Commercial nuclear plants in the United States have been governed by analog instrumentation since they were built, and the logic was sound at the time. Analog systems are deterministic: a needle moves, a relay trips, and the chain of physical causation is simple enough to license. Digital controls introduce software, and software can fail in ways that are genuinely harder to characterize.
A bug does not announce itself the way a worn contact does. Replacing analog with digital at a commercial US reactor requires the operator to prove, to a very high standard, that no new failure mode has been introduced, and that proof has proved expensive and slow.
So almost every American reactor still uses digital technology only at the sensor level, where measurements are taken, not at the control level, where decisions are made and rods are moved. That regulatory gap is exactly what one small Indiana reactor stepped into.
Ten microwaves of power, one reactor unlike any other
Deep underground at a Purdue University building sits a fully digital nuclear reactor generating only enough power to run about 10 microwaves. Rather than converting nuclear heat into grid electricity, the reactor conducts experiments that help engineers understand nuclear power more deeply, and it was never built to light a single bulb.
The reactor was built in 1962 and converted from analog to digital in 2019 with support from a federal nuclear energy office. The conversion replaced every dial and relay in the control room with screens, keyboards and cables, turning an early sixties teaching tool into something the US nuclear industry had never formally licensed before.
Although some countries already operate reactors with digital controls, this is the only fully digital reactor licensed by the US Nuclear Regulatory Commission. That distinction, earned on a university campus, turned out to matter far beyond Indiana.
The July experiment that proved the point
One of the most remarkable tests was conducted in the summer of 2026. A team from Idaho National Laboratory and two universities demonstrated remote power adjustments without any manual control rod manipulation at the Indiana site, meaning engineers sitting in Idaho Falls fine-tuned the reactor’s operating state and the machine responded as commanded.
Central to that experiment is a digital twin, an AI-powered replica of the reactor that receives live sensor data and runs predictive algorithms against it. The twin enables machine learning to predict reactor power stability with approximately 99 percent accuracy, assess remote multi-reactor operation, detect cybersecurity anomalies, and simulate encrypted communication for safer, lower cost future nuclear systems.
Because the reactor already operates entirely through digital controls, researchers can test new software under realistic conditions rather than relying solely on simulations. That combination, a real licensed reactor with a fully digital control room, is what makes it irreplaceable as a test platform. The facility director put the significance plainly: “Our switch to digital instrumentation and control signaled to the nuclear industry that this is possible in the U.S.”
Where the limits still sit
The regulatory pathway for full digital conversion at a large power-producing unit remains long and expensive, and the Nuclear Regulatory Commission has not moved to change the standard that has kept analog controls in place for decades. None of this means a commercial reactor will run on a laptop and an ethernet cable next year.
The cybersecurity question is also genuinely open. Researchers are testing AI-assisted monitoring, secure communications and cyberattack detection tools, including systems that could eventually enable remote reactor operation. A failed neutron sensor at an 867 MW Illinois reactor recently showed how a single digital reading can cascade through shutdown logic in unexpected ways, and that lesson sits directly beside the work being done here.
Even so, the complication is a design problem, not a verdict. Every barrier identified at the small reactor is a barrier that a larger machine never has to discover the hard way.
What a 10-microwave reactor tells the industry about its future
The case for this work sharpens considerably when set beside the coming generation of small and micro reactors. An associate director of the facility imagines a future where staff in a control room hundreds or thousands of miles away monitor multiple reactors at once. “We could minimize the operation and maintenance costs,” he said. That vision matches precisely the direction the industry is heading, and the economics of the next nuclear wave depend on remote operation.
Remote operation, in turn, depends on digital controls that someone has already proven safe enough to license. A 1 MW microreactor reached criticality in Idaho in 150 days, a machine that would be uneconomic to staff with a full on-site crew indefinitely.
To expand its research, the university is building a second digital twin and a full-scale reactor control room housing a new model of a scaled-down light water reactor testbed, funded by a federal energy consortium, to test AI, cybersecurity defenses and remote control systems. A reactor that produces the energy of ten kitchen appliances is, by any honest measure, a modest machine. But the proof it carries, that a fully digital nuclear control system can be licensed, operated safely, and adjusted from far away, is worth considerably more than its output.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
