Valar Atomics’ Ward 250 Reactor Under Construction Daria Nagovitz/Valar Atomics
Despite contributing nearly one-fifth of the U.S. power generation, nuclear energy in the country has seen stagnation for decades. Factors such as regulatory challenges, public apprehension, and affordable energy sources have hindered growth, coupled with factory closure moratoriums and insufficient funding for new nuclear technologies. However, an increasing demand for power, especially from data centers, is reviving interest in nuclear energy. The Department of Energy is moving rapidly to rectify this delay with its reactor pilot program, aiming for a major milestone by mid-2026.
This initiative is part of the Department of Energy Strategy, which seeks to quadruple nuclear production by 2050. Eleven companies focused on advanced nuclear reactor technology have been chosen to participate, with expectations for at least three to reach criticality – a stable and self-sustaining nuclear fission state – by July 4, 2026.
“We intentionally set very ambitious deadlines,” stated Leslie Dewan, a nuclear engineer specializing in advanced reactor technology. “One of our pilot’s goals is to evaluate which concepts thrive under real-world conditions.”
The reactor designs under development range from molten salt and hot gas reactors to fast reactors, sodium-cooled systems, and pressurized water reactors. Notably, California-based Valar Atomics is regarded as a frontrunner, especially with its Ward 250 high-temperature gas reactor.
High-temperature gas reactors utilize small particles of uranium surrounded by carbon and ceramic coatings, transforming them into self-contained fuel units. This coating ensures that the particles remain intact even at extreme temperatures, creating a protective safety barrier to contain any radioactive materials.
Fuel particles are embedded within graphite blocks, which serve as the reactor core, featuring channels for helium gas circulation. The nuclear fission reaction generates heat that boils water, producing steam to power generators and generate electricity. The helium gas then returns to the reactor for reheating.
Valar broke ground on Ward 250 in September, marking it as the second company to initiate construction, following Texas-based Arlo Atomics which began in August. Valar has achieved the first low-temperature criticality, demonstrating a self-sustaining fission reaction under controlled conditions, offering valuable data to confirm core physics. “It’s not equivalent to constructing and operating your integrated test reactor at full power,” Dewan explained.
Texas-based Natura Resources is also developing molten salt reactors known for their inherent safety features, although they function differently. In these designs, uranium is dissolved in molten salt, heated by fission. A pump circulates this liquid salt to a heat exchanger, generating steam or driving a turbine. If overheating occurs, the molten salt expands and melts an emergency “freeze plug,” allowing the fuel to safely drain and preventing chain reactions.
“Molten salt reactors operate at atmospheric pressure, containing any accidents to the plant site,” emphasizes Dewan. “Even in a total power failure, the reactor can come to a safe stop without on-site operator intervention.”
Natura has not yet commenced construction but secured a permit from the Nuclear Regulatory Commission to build a 1-megawatt research reactor. Additionally, it has recently acquired Shepherd Power, which will enhance its supply chain and regulatory expertise to expedite its technology’s implementation. Dewan noted, “We have fostered a highly collaborative relationship with the NRC,” though she cautioned, “the challenges posed by molten salts, which are corrosive and radioactive at high temperatures, should not be underestimated.”
With the critical deadline approaching in about six months, Valar, Natura, and nine other companies in the pilot program must work at an exceptional pace to meet this goal. However, this is just one of many challenges that must be navigated.
“The true evaluations will center around whether we can safely power the reactor on and off, operate it for extended periods at design temperatures, and ensure that materials and fuel perform as anticipated. All of this must be reliably demonstrated to gain trust from the NRC and future clients,” Dewan concludes. “I see the 2026 date as the beginning of an intriguing data collection phase, far from the conclusion.”
Topics:
- Nuclear Energy/
- 2026 News Preview
Source: www.newscientist.com
