Nuclear powerNuclear Micro-Reactors

The idea of a nuclear power plant today evokes images of large cooling towers and expansive, warehouse-size buildings. Such facilities generate about a fifth of electricity in the United States without emitting greenhouse gases. A different picture of nuclear energy is emerging, however, in the form of micro-reactors that could fit on the back of a truck or inside a rocket to space. The promise of these micro-reactors is to provide the same reliable, zero-carbon power in remote settings or to support electrical power grid recovery.

Experts at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are developing strategies to bring micro-reactor concepts closer to commercial reality, working together with private industry and federal regulators. A micro-reactor might have a capacity of anywhere from a few kilowatts to 20 megawatts — far less than even the smallest operating U.S. nuclear power plant, which has a capacity of 581 megawatts. The low electricity output allows micro-reactors to have a smaller physical size and reduced costs, which would be enabled through factory manufacturing and design simplification.

Aside from being compact, micro-reactors must be designed to operate safely for many years — perhaps several decades. They can also be self-controllable, operating without the need for a constant human presence. While it’s possible to build such a reactor with today’s technology, it might not have the portability or the efficiency needed to operate on a military base, for example, or in an Arctic community where renewable alternatives such as wind or solar energy are not feasible.

“At Argonne, we’ve identified a few advanced technologies that could push micro-reactors much further,” said Nicolas Stauff, principal nuclear engineer. Stauff is collaborating with companies such as HolosGen under DOE’s Advanced Research Projects Agency-Energy’s (ARPA-E) Modeling-Enhanced Innovations Trailblazing Nuclear Energy Reinvigoration (MEITNER) program for micro-reactor design and modeling efforts. He is also working with DOE’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program, an effort spanning seven national labs, to develop new computer-based tools and capabilities for the design, analysis and potential licensing of nuclear reactors including micro-reactors.

As work proceeds on the design and deployment side, other experts at Argonne are lending technical assistance to regulators in determining the requirements for safety, safeguards and security for micro-reactors. “With new reactor designs coming online in the next decades, we are creating a framework to ensure confidence in how these reactors are being built, sited and constructed,” said Andrew Breshears, principal nuclear chemist at Argonne.