3Q: Why “nuclear batteries” offer a new approach to carbon-free energy

Recently, a group of nuclear experts proposed in The Bridge, the journal of the National Academy of Engineering, that we might be standing on the edge of a transformative shift in nuclear power. Drawing a parallel to the transition from large, centralized computers to the ubiquitous PCs of today, they foresee a future with a new breed of compact, affordable reactors, akin to oversized batteries, poised to revolutionize energy generation.

These envisioned systems could supply heat for industrial processes or power military bases or neighborhoods independently for five to ten years before returning to the factory for refueling and maintenance. Coined "nuclear batteries" by the authors—Jacopo Buongiorno, MIT’s TEPCO Professor of Nuclear Science and Engineering; Robert Frida, a founder of GenH; Steven Aumeier of the Idaho National Laboratory; and Kevin Chilton, retired commander of the U.S. Strategic Command—these small-scale power plants could play a pivotal role in mitigating climate change by decarbonizing global electricity systems due to their straightforward operation.

MIT News sought insights from Prof. Buongiorno regarding their proposal.

Q: Modular nuclear reactors have been discussed for some time. What sets this "nuclear battery" proposal apart?

A: Our concept pushes the boundaries of factory fabrication and modularity to the extreme. Previous proposals focused on reactors with outputs ranging from 100 to 300 megawatts, significantly smaller than traditional gigawatt-scale nuclear reactors. While these could be assembled from prefabricated components, they still required on-site assembly and extensive site preparation, representing an incremental improvement rather than a transformative leap.

The nuclear battery concept represents a paradigm shift due to its minute scale and power output—around 10 megawatts. Entire power plants can be factory-built to fit within a standard container. This offers numerous economic advantages. Deployment is swift, typically within weeks, transforming nuclear energy into an on-demand service rather than a protracted mega-project.

Q: You propose widespread deployment, even in residential areas. How can people trust the safety of such plants?

A: The designs for nuclear batteries prioritize robustness, a key selling point for this technology. Their small size enhances safety in several ways. Firstly, minimal residual heat requires removal upon reactor shutdown. Secondly, the reactor core's high surface-to-volume ratio facilitates efficient cooling without external intervention. Essentially, the system self-manages.

Moreover, a compact, sturdy steel containment structure surrounds the reactor, guarding against radioactivity release. To bolster security, we envision situating these batteries underground at most sites, providing additional protection against potential threats.

Q: What assurances do we have regarding the functionality of these reactors, and what steps are needed for widespread availability?

A: NASA and Los Alamos National Laboratory demonstrated a microreactor for space applications within three years (2015-2018), costing $20 million, a fraction of traditional large nuclear plant expenses. Presently, numerous companies are developing their designs, with Westinghouse aiming to showcase a nuclear battery utilizing heat pipe technology within three years.

These pilot plants, such as those planned at Idaho National Laboratory, undergo rigorous testing to ensure performance under extreme conditions, instilling confidence for widespread commercial deployment.

Nuclear batteries promise resilience across sectors by delivering dependable, carbon-free electricity and heat precisely where needed, reducing reliance on costly energy transmission and storage infrastructure. If realized on the scale envisioned, they could substantially curb global greenhouse gas emissions.

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