Low-Energy Fridays: America’s 250th birthday present: More nuclear power plants
Last year the Trump administration offered a bold challenge to the nuclear industry. In May of 2025, the administration issued a series of executive orders aimed at reducing regulatory barriers and speeding up the timeline for the construction of new nuclear plants. The orders also included a goal: before the nation’s 250th birthday, for at least three new nuclear reactors to “reach criticality.” Demonstrating that a design can reach criticality means proving that it can produce energy in a sustainable yet safe manner. This is a key step in approving a new nuclear design for commercial use. At the time, critics scoffed at the rushed timetable.
But a funny thing happened on the way to the semiquincentennial. On June 4th, a reactor designed by Antares Nuclear went critical in a demonstration at the Idaho National Laboratory. Then, on June 18th, another nuclear reactor designed by Valar Atomics achieved criticality at a lab in Utah. It’s still unclear whether the official goal of criticality at three new reactors outside the national labs will be reached by Independence Day, but the tests show that progress is being made on rapidly shepherding new reactor designs through the approval process.
Beyond demonstrating a growing interest in nuclear power, these new designs aim to overcome some of the difficulties faced by traditional nuclear power plants. We are accustomed to thinking of nuclear plants as being big not only physically but in terms of how much power they can produce. A single light water nuclear reactor, for example, can produce a gigawatt (GW) of electricity. Unfortunately, big reactors have traditionally also been expensive reactors, and the large upfront capital expenditures needed to build an old-style nuclear plant can leave those reactors vulnerable to changes in the market.
But there is nothing that prevents nuclear power from being produced on a smaller scale. One functioning research reactor at Texas A&M University is so small it can barely produce enough power to light up a 5-watt light bulb. The Antares and Valar reactors are larger, but much smaller than current commercial plants. The Antares reactor design is rated to produce between 100 kilowatts (kW) and 1 megawatt (MW) of electricity. The Valar reactor, a bit bigger but still tiny relative to traditional plants, is designed to produce around 5 MW of electricity. Even one of these smaller reactors could produce enough electricity to power several thousand homes, or could be used to power commercial buildings, or other facilities. These smaller profiles not only reduce the upfront cost needed to build the plants, but also open up possible new uses, such as remote military applications or data centers.
Another advantage of the new designs is improved safety features. Traditional nuclear power plants in the United States have a good safety record, but do require active intervention to prevent a meltdown should something go wrong. Many advanced nuclear designs, by contrast, include passive safety features, meaning if something should go wrong the reactor would shut down automatically without requiring intervention from a human or computer system. For example, some designs suspend cooling water over the reactor with magnetized bars. Should the power fail, gravity would cause the reactor core to be doused with the water, preventing a meltdown.
With many different potential designs, it is impossible to say which might ultimately win out. It’s not a coincidence, however, that so much innovation is happening in the nuclear area now. For a long time, the Nuclear Regulatory Commission (NRC) provided a barrier to the development of new nuclear power through long and costly permitting and approval processes. The current administration, by contrast, has approached its role very differently, focusing on helping to release pent-up innovation through streamlined regulatory approval requirements that fit new designs. Whether nuclear power succeeds will therefore be more a matter of market forces than of bureaucratic delays.