Next Generation Radioisotope Nuclear Space Propulsion in the 3-Kilowatt Range

Ultra Safe Nuclear has been funded by the Defense Innovation Unit (DIU) to demonstrate a chargeable, encapsulated nuclear radioisotope battery (called EmberCore) for propulsion and power applications in space. This ‘next-gen’ radioisotope system will be able to scale to 10x higher power levels, compared to plutonium systems, and provide more than 1 million kilowatt hours (kWh) of energy in just a few kilograms of fuel.

It seems like they are leveraging their pebble bed encapsulation techniques for radioisotope power.
EmberCore is a nuclear chargeable ceramic (NCC)
that produces heat and x-rays without the need for externally applied power. An EmberCore is composed of individual “embers” made from a family of commercially available, inert isotopes charged with neutrons in a nuclear reactor.

By customizing the isotope selection and charging process, customers receive a heat and/or x-ray source matched to their mission duration, power level, and radiation tolerance. EmberCore does all of this while providing a vastly simplified regulatory path compared to conventional plutonium- or strontium-based alternatives.

The most powerful plutonium radioisotope thermoelectric generators launched into space produced about 300 watts of power. The EmberCore could scale to 3 kilowatts.

The EmberCore architecture scales by combining individual embers to generate enough thermal power to meet mission requirements, from milliwatt-scale to kilowatt-scale.

EmberCore units are packaged inside a radiation-absorbing shield, keeping people and electronics safe from harm while simplifying the integration process.

EmberCore’s shield can be customized to provide high intensity x-ray sources for scientific and engineering applications without the need for externally applied power.

EmberCore can be paired with power conversion systems to act as a long duration battery for missions needing long duration operation far from any other energy sources.

When combined with electric propulsion technology, EmberCore-powered batteries can enable speeds of up to twenty times that of chemical rockets.

The Defense Innovation Unit (DIU) is advancing approaches to accelerate ground and flight testing for nuclear-powered prototypes of this next-gen radioisotope concepts. The ultimate objective is to launch a successful orbital prototype demonstration in 2027 of each approach.

It will give small spacecraft the ability to maneuver at-will in cislunar space and enable high-power payloads that will support the expansion of Department of Defense (DoD) space missions.

Still Working on Factory Mass Produced High Temperature Pebble Bed Reactor

Ultra Safe Nuclear has been working on a fourth generation terrestrial powerplant reactor. The Micro Modular Reactor (MMR®) system is a 4th Generation nuclear energy system that will delivers safe, clean, and cost-effective electricity and heat to remote mines, industry, and communities. It is the leading SMR project in Canada and the first so-called “fission battery” concept worldwide.

SOURCES- Ultra Safe Nuclear
Written By Brian Wang,

6 thoughts on “Next Generation Radioisotope Nuclear Space Propulsion in the 3-Kilowatt Range”

  1. I will ask the obvious questions, just to show that I can’t read.

    If it is similar to HTR-10 TRISO pebble bed reactor that has been operating at full power since 2003, then what are the issues holding it back 20 years later? Economics? Regulatory? Why hasn’t China been manufacturing/iterating like crazy, then selling to rest of world?

    Inquiring minds want to know…

  2. I wonder how this compares to artificial diamond encapsulated radioactive waste batteries from NDB:
    NDB is pretty far along since forming in 2019, with a presence all over the world, and a proven nanoscale technology and major news coverage.
    They see applications in everything from auxiliary EV batteries that will last for years, to 2 year smartphone batteries.
    One downside possibly common to both: if you don’t use the energy constantly, there’s a risk of runaway overheating. NDB says cars powered in part by their batteries might have to power the grid if the cars are not used for long periods; a nice problem to have, perhaps.

    • “if you don’t use the energy constantly, there’s a risk of runaway overheating”

      I don’t see how that would be a problem. It produces heat constantly & if you don’t have a constant demand you would just have to throw away some of the energy. For better economics you want energy use to match what is available, but having extra to throw away isn’t all that horrible.

    • I wondered where these guys were after these years.

      Good to know they are working on it yet.

      If they deliver, this will change a lot of markets. My concern is precisely how to manage the continued energy generation. If there is any risk of fire or melt if the energy isn’t used, then it will be more restricted than touted in their promos.

      Still, very good for many applications that are simply impossible today. And certainly whatever these RTGs do, NBD can probably do better.

      • Well, if you’ve got energy you don’t know what to do with, you can always run Proof of Work on it, or maybe SETI@Home, or some other distributed energy/computing cycle sink.


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