Aalo Atomics low-pressure microreactors

This design choice is really about turning a nuclear plant from a giant pressure vessel surrounded by a massive concrete shell into a smaller heat source that behaves more like industrial equipment. Conventional reactors use water kept under extreme pressure so it can carry heat without boiling, which means pipes, pumps, valves, and the reactor building all have to be built around the risk of a pressurized release. Aalo instead uses liquid metal coolant in a low pressure loop, following the same basic microreactor path proven out in MARVEL, which lets the reactor package stay physically smaller and easier to factory build.

• In a standard light water plant, high pressure water systems and containment are central safety hardware. NRC reactor manuals describe emergency core cooling, high pressure injection, and containment pressure control as core parts of these plants. Removing the high pressure water loop eliminates a large share of that mechanical and civil complexity.
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• MARVEL is a useful comparison because it uses uranium zirconium hydride fuel, sodium potassium coolant, and natural circulation cooling at low pressure. Aalo is adapting that playbook to a commercial 10 MWe reactor, then bundling five reactors with one turbine, so the no high pressure architecture is directly tied to factory manufacturing and truck transport.
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• The practical result is not just a smaller plant footprint. It also changes siting economics. Aalo is targeting data centers and industrial loads that care about fitting power generation onto a constrained site, avoiding large water needs, and installing repeatable modules instead of building a custom gigawatt scale nuclear campus.
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Going forward, the companies that win in advanced nuclear for data centers are likely to be the ones that make the reactor feel less like a mega project and more like a manufactured product. Low pressure coolant systems, passive heat removal, and compact balance of plant are what make that possible, and they are central to Aalo's path from one test unit to fleets of deployable Pods.