The Nuclear Power Industry’s Hidden Problem

The nuclear power industry has been experiencing a renaissance, with startups securing funding to develop advanced reactors with the goal of lowering costs. However, recent projections suggest that these reactors may not be cost-competitive anytime soon.

Apollo Atomics, a startup founded by Assil Halimi and Drew Walker, believes that the reason for this is that companies have been focusing on the wrong problem. Instead of designing a new reactor, Apollo is rethinking the way thermal energy is converted into electricity.

A New Approach to Steam Generators

According to Halimi, the CEO of Apollo, the key to making nuclear power cheaper lies in the steam generator, a necessary but unsexy component of a power plant. The steam generator produces steam from the reactor’s coolant loop to drive a turbine. Most steam generators are hand-built and several stories tall, but Apollo’s design can be mass-manufactured and is about the size of a person.

This compact design has allowed Apollo to build a reactor that is 40-times smaller than one that uses a conventional steam generator. By shrinking the steam generator, Apollo has been able to make the whole system more compact and efficient.

Apollo’s design is based on research from MIT and has been able to achieve a significant reduction in size while maintaining the same level of performance. The company’s goal is to make nuclear power plants more competitive with natural gas, and it believes that its design can achieve this.

Improving Efficiency and Reducing Costs

Existing steam generators have left plenty of room for improvement, Halimi said. Old designs borrow heavily from those used by coal and natural gas power plants, but both of those fossil fuels have far lower energy density than nuclear fuels like uranium. As a result, current generators fail to make the most of nuclear fuel sources.

Apollo’s generator would thread the two fluid loops through a compact block of metal that’s laced with needle-thin channels, allowing heat to be transferred more efficiently. This setup enables the company to shrink its size while maintaining the same level of performance.

With the compactness of the generator in mind, Apollo plans to assemble the reactor and steam generator in a factory rather than on site, which is the case with nuclear power plants today. This approach is expected to result in significant labor savings and reduced costs.

Between the labor savings and smaller size, Halimi expects Apollo to be able to build a 300-megawatt power plant in less than 24 months, and predicts the reactor itself to cost four to five times less to produce than existing designs.

Apollo has already built a small, 40-kilowatt reactor at MIT to demonstrate the technology. It plans to offer three sizes, ranging from 10 megawatts-electric to 300 megawatts.

FCVC led the funding round, with Telesoft Partners, Y Combinator, Alumni Ventures, Robinhood Ventures, Nucleation Capital, Pelion VC, Duke Capital Partners, New Era Ventures, Orange Collective, Stanford University, E14 Fund, and Neutron Power Ventures participating. Apollo was part of Y Combinator’s Spring 2026 batch.