Your basement has a thorium-fueled nuclear reactor tucked away in the corner next to the chest freezer, and it was 3D printed to fit your home.
While that may sound a bit far-fetched, and at this point it certainly is, new research is postulating the idea that small-scale nuclear reactors might one day help meet the demand for domestic energy.
The designers at Solid Ideas have used 3D printing to model parts for such reactors, and the AMAZE project in the UK is already working on developing the necessary complex metal parts made to withstand temperatures at 1000°C for use in the ITER fusion reactor.
"To build a fusion reactor like ITER, you somehow have to take the heat of the sun and put it in a metal box," said David Jarvis, the head of new materials and energy research at the European Space Agency. "If we can get 3D metal printing to work, we are well on the way to commercial nuclear fusion."
So why couldn't you scale down a nuclear reactor for domestic use? And what keeps that from happening now?
Some existing designs generate power using "nuclear waste" like depleted uranium and plutonium produced by this generation of conventional reactors. Depleted uranium, or U-238, is U-235 without the "fissible" material. Some designs use the much less volatile thorium as fuel, and thorium is abundant in nature and virtually useless in making weapons.
Estimates say that world energy consumption will have doubled between the years 1995 and 2035 and those figures present a monumental challenge for engineers and scientists tasked with developing and deploying methods and power sources capable of meeting that need and reducing emissions.
The journal Progress in Nuclear Energy has published a paper which outlines the possibility that those growing power consumption needs might one day be met using what are called Small Modular Reactors, or SMRs.
The lead author of the work, Dr. Giorgio Locatelli of the School of Engineering at the University of Lincoln, UK, says a version of the technology, the Light Water Reactor (LWR), might just turn the trick.
"With fusion-based power plants not currently being considered viable for large-scale deployment for at least 40 years, other technologies must to be considered," Locatelli said. "Renewable and high efficiency combined gas-fired plants, along with nuclear power plants, are regarded as the most suitable candidates, with Small Modular Reactors (SMRs) developing as a favored choice."
It's the "passive systems" model of SMRs, a methodology which reduces the effects of human error on their operation, which would make them suitable for widespread adoption. The small size of SMRs, and what we're talking about here would currently take up about the same space as a strip mall, might produce around 300 megawatts of power. That's enough to serve 45,000 homes.
And while SMRs are real-deal reactors, they're much larger than their radio-thermal generator (RTG) cousins of the type used to power spacecraft. SMRs use controlled nuclear fission to generate power. The RTG uses natural radioactive decay to drive a thermoelectric generator.
The US Department of Energy is sufficiently interested in the technology to the extent that they're offering $452 million in matching grants to private investors willing to take on the challenge.
SMRs are hardly science fiction. The devices have been used to power nuclear submarines for the last sixty years, and they have a host of advantages over conventional reactors. They're cheaper to construct and run, they're much smaller and they can be assembled and tested in controlled factory conditions for delivery directly to their final site.
And as SMR designs may use gases, metals or salt for cooling, they avoid the major hazards of water-cooled reactors; namely, a lack of the need for high-pressure containment structures.
Because they're much, much smaller, some SMR designs would allow for them to be cheaply installed below ground making them easier to protect from security risks and earthquake damage.
Westinghouse already makes a version of the SMR capable of generating 225 megawatts which can be built in 18 months. At only 89 feet long and 32 feet in diameter, it's small enough to be shipped by rail car to a site.
A version of the technology built by Babcock and Wilcox is based on US Navy reactor designs and it can be air-cooled, albeit at the cost of somewhat reduced power production. Called the mPower, the reactor uses a "passive" cooling system integrated into the design. The mPower only requires refueling once every four years, and that happens by replacing the entire core cartridge rather than dismantling the entire device.