” … Cheap, Portable Nuclear Reactor.”

Concept image of Radiant reactor

“Their microreactor, which is still in the prototype phase, outputs more than 1MW, which Radiant says is enough to power approximately 1,000 homes for up to eight years. It can be easily transported by air, sea, and road, meaning it will bring affordable energy to communities without easy access to renewable energy, allowing them to reduce their reliance on fossil fuels.

Radiant founder and CEO Doug Bernauer is a former SpaceX engineer who worked on developing energy sources for a future Mars colony during his time at the private space enterprise. During his research into microreactors for Mars, he saw an opportunity for developing a flexible, affordable power source here on Earth, leading to him founding Radiant with two other SpaceX engineers. In an interview with Power, Bernauer said “a lot of the microreactors being developed are fixed location. Nobody has a [commercial] system yet, so there’s kind of a race to be the first.”” interestingengineering.com

Comment: How is this very different from the reactors that are powering the latest planetary rovers? pl


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19 Responses to ” … Cheap, Portable Nuclear Reactor.”

  1. TTG says:

    Most spacecraft use radioisotope thermoelectric generators (RTGs) for their low power applications. These generators rely on the slow radioactive decay of the fuel rather than a fission reaction. The heat of the radioactive decay is converted to electrical power by thermocouples. The Soviet/Russian space programs have used fusion reactors to a far greater extent than we have. For spaceship propulsion, these reactors are now being used to provide superheated fuel for thrust or to produce electric power and superheat for electric ion drives.

    I can’t tell if this Radiant portable power plant uses decay or fusion. I’m leaning towards fusion given the 1 MW proposed output. Current RTGs used in space have very low output.

    • TTG says:

      Oops. Meant fission rather than fusion for those Russian spacecraft. I’m sure they wish they had fusion powered spacecraft.

    • EEngineer says:

      I think you meant to say fission.

      RTGs use TECs (Peltier junctions) running in reverse to generate power. It’s called the Seebeck Effect. It’s occasionally used to power remote sensors on hot oil pipelines and such.

      The photo only shows the core. It appears to be a High-Temperature Gas-Cooled Reactor (HTGR). You still need to turn that thermal energy into electricity. A steam plant is the classic way to do that. A gas turbine could be used though. Running either a slightly lower efficiency (higher exhaust temperature) could be done to make the waste heat the actual product. For instance a lot of buildings in NYC are heated by a central steam plant. One of the under street lines ruptured a few years ago…

      • TTG says:

        Speaking of turbines, I was impressed by this off grid Brit’s personal water turbine system. If you have the topography and water, this seems to be the way to go. His turbine is only the size of a large lawnmower engine and his water supply is fairly small, but he can run his metal shop tools with the output from that system.


        His discussion of his power system begins at the 6 minute mark.

        • Pat Lang says:

          You did not actually address my question which sought an answer to the difference between the nuclear thingies in the Mars rovers and this proposed town powering reactor.

          • TTG says:

            Our rovers use a radioisotope thermoelectric generator (TEG) which relies on heat generated by fuel decay as opposed to a fission reactor. Is sounds like just another name for the radioisotope thermoelectric generator that I mentioned. The Perseverance rover generates 110 watts from this TEG. Everything I read about the Radiant reactor points towards a fission reactor to get to the 1 MW range.

          • TTG says:

            I found a more descriptive article on the technology used in these small portable reactors.

            A California based company called Oklo is advertising “the Aurora advanced fission power plant, also called a fission battery. The plant produces about 1.5 MW of electric power, while having the ability to produce usable heat. The plant uses metal fuel to produce heat, an advanced fuel type which is well demonstrated with decades of experimental data. Heat pipes carry the heat to a heat exchanger, and a power conversion cycle converts the heat into electricity.”

            The Oklo reactor will be the first demonstration project to receive “high-assay, low-enriched uranium (HALEU) nuclear fuel from Idaho National Laboratory (INL) to aid a first-of-its-kind demonstration of its Aurora micro reactor, which could begin in 2024.”

            These micro reactors are a smaller class than the modular reactors like the modular ones being built by NuScale. Micro reactors operate below 10 MW. The small modular reactors like NuScale have capacities between 60 and 300 MW.

  2. TTG says:

    Found an article on our past attempts at portable nuclear power generators. While their use on ships and subs have been wildly successful, land based portable plants have left a pretty rough record. I found this because I remembered a half hour documentary put out by the US Army detailing the establishment of Camp Century under the Greenland ice pack along with the PM-2A “portable” nuclear reactor brought in by sledges. It created a radioactive mess.


    The safety and containment technology has come a long way since then, but the possibility of creating neighborhood sacrifice zones is something Radiant will have to address whether it’s a realistic possibility or not. Hell, the idea of radon in your cellar is enough to give many the willies.

  3. Babeltuap says:

    France is around 70% nuclear. If the place where the climate accord was signed loves it then what’s the big deal? Even the current tech it is safe enough. Why do we need some major breakthrough? I’m all for it, don’t get me wrong but I don’t think the climate folks and their crony sun and wind farms are going to allow it anytime soon.

    • TTG says:

      Oddly enough, the Green New Deal doesn’t call for the immediate dismantling of nuclear power plants. They see nuclear as a viable bridge to all renewable power. This half hearted acceptance of nuc power was the reason Gabbard did not sign up for the GND. She wants all nucs out now.

      Why the Germans decided to shutter their nuclear plants before they had a viable replacement is beyond me. I lived fairly close to one south of Heidelberg for a while. I don’t remember any of the neighbors too worried about it. These smaller plants like this shipping container size portable one or those prebuilt modular reactors that can be barged or trucked in should be cheap enough and safe enough for power companies to give ’em a go.

  4. Deap says:

    If it can heat an Aga stove, half the battle is won.

  5. Deap says:

    Power is what power does – this is creepy. Xingjiang now bristles with global capacity stealth missile silos.


    A new sheriff in town. Does China just want our land or our people too?

  6. Fred says:

    So what is the actual cost per MW? While it is a great idea it doesn’t seem to be cheap or they would have commercial backing already.

    • TTG says:

      No, it doesn’t seem to be cheap at all. And it all depends on development and long term support from big government. Long term investment is certainly not the strong point of private business. However, outside of the development costs, I did find this statement. “Over the longer term, factoring in experience and generational development of its technology, Oklo is targeting a cost competitiveness of $0.05/kWh.” That will sure beat the 12 to 14 cents per kWh we pay now, but I’ll be real damned old or worse by the time that happens.

      • Pat Lang says:


        IMO. You guys are all too negative about this.

      • Fred says:


        I’m all for building one or two of these to see if the design works. If so ship one to Mars when you start the colony. But “generational development of its technology” means decades. Base load generation is still going to be much more efficient than these.

  7. William M Hatch says:

    I am a fan of nuclear power. My father worked with a power company. In the 1950’s when nuclear was the new technology, I read an article in Dad’s company news letter that stated that the company’s primary concern with nuclear power generation was that the power would be so cheap to generate that the company would have to give away the electricity & make their money in distribution.

    Government regulation eliminate that problem.

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