Friday is here, and the 'A Taste of Science for the Weekend' corner is back — number 69.
This time: the next generation of small modular nuclear reactors, and their connection to spacecraft, data centers, and green hydrogen.
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You may not have heard of SMR reactors yet, but they could well be humanity's new dawn, and many companies around the world are making enormous efforts to bring them to market as soon as possible.
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A nuclear reactor is a massive machine for generating energy.
The rationale behind large reactors is that doubling a reactor's output does not double its operating costs — so the larger the reactor, the more economical it becomes.
But size has its drawbacks: building a giant nuclear reactor requires transporting equipment to the site, and construction takes many years.
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SMRs are built on a different advantage — their small size makes it possible to manufacture them on a production line and ship them to wherever they will be used.
The artificial intelligence revolution has made them critical, because data centers are being built at a record-breaking pace and require enormous amounts of energy that the existing generation and transmission infrastructure simply cannot handle.
Tech giants are investing vast sums in developing these reactors, with the vision that every data center will be powered locally by its own dedicated nuclear reactor — independent of the power grid, with zero carbon emissions, and at costs that will continue to fall as the technology matures.
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A classic nuclear reactor uses water as a coolant.
In such a reactor, uranium (typically) undergoes fission in a chain reaction, releasing thermal energy. The heat is absorbed by water, which is used to produce steam that spins a turbine to generate electricity.
A water-based small modular reactor operates on the same principle, but its heat dissipation is passive and can continue even during a power outage, making it safer against meltdown.
The drawback of a water-based reactor is that, to prevent the water from boiling off, it must be kept under enormous pressure — which can lead to leaks, rapid vaporization of the coolant, and overheating of the core.
Other designs use gas as a coolant. These reactors can operate at very high temperatures, and rather than generating electricity, their intense heat is used directly in energy-intensive industries such as metal production or green hydrogen generation.
Other approaches use liquid metal, which allows the reactor to operate at high temperatures while maintaining low pressure — since heat is conducted away rapidly through the metal — or molten salt, which is considered especially safe.
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The video shows Rolls-Royce's vision for developing a micro nuclear reactor — a reactor small enough to serve as a propulsion source for spacecraft.
The longer-term vision is to place a small nuclear reactor on the Moon, where it would provide abundant energy to support a viable human presence.
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A single small nuclear reactor could supply energy to tens or even hundreds of thousands of homes, with minimal maintenance and fuel loads that last many years at a time.
It could reduce dependence on polluting energy sources and long, wasteful transmission lines, and ensure that power outages remain localized and affect only relatively small areas.
Using its energy to produce green hydrogen could be the next breakthrough in transportation — replacing polluting batteries and lengthy refueling stops with vehicles and aircraft that generate electricity on the move using liquid hydrogen.
There are, of course, risks: radiation leaks, the potential use of plutonium produced in the reactor to develop nuclear weapons, and radioactive waste that will remain a serious environmental problem with no easy solution.
But if these challenges can be overcome, humanity will step into a new energy era — clean, and full of extraordinary promise.
Shabbat Shalom 😊
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Video credit: Rolls-Royce
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