The Inside Story of Google’s Quiet Nuclear Quest

In 2014 I went to my managers with an audacious proposal: Let’s create a nuclear energy research and development group at Google. I didn’t get laughed out of the room, maybe because Google has a storied history of supporting exploratory research. While I did not propose that Google build a nuclear lab, I felt certain that we could contribute in other ways.

I had some credibility within the company. I joined Google in 2000 as its first director of engineering, and helped make the company profitable with the pay-per-click advertising systemAdWords, in which companies bid to place ads on our search-results page. In subsequent years I got interested in energy and was part of the design team for Google’s firstenergy-efficient data center. Then, in 2009, I was recruited into Google’s effort to makerenewable energy cheaper than coal (an initiative we called RE<C).

While that last project didn’t pan out as hoped, I learned a lot from it. AGoogle-McKinsey study conducted as part of the project drove home the point that the intermittent power sources, solar and wind, need reliable backup. Therefore, efforts to decarbonize the grid affordably depend on what happens with always-on or always-available hydro, geothermal, and nuclear power plants.

I grew up in Ontario, Canada, which achieved a climate-friendly electric grid in the 1970s by deploying nuclear power plants. It seemed to me that recent improvements in reactor designs gave nuclear plants even more potential to deeply decarbonize societies at reasonable cost, while operating safely and dealing with nuclear waste in a responsible way. In 2012, after RE<C, my personal interest in nuclear picked up and I became an executive producer for the documentaryPandora’s Promise, in which environmentalists argued that nuclear power could help us transition away from fossil fuels while lifting people in developing countries out of poverty. I came away from this filmmaking experience with a handful of solid contacts and a determination to get Google involved in advancing nuclear.

The proposed plan for the nuclear energy R&D group (affectionately known as NERD) was based on input from similarly minded colleagues. The problems we could address were determined by who we could work with externally, as well as Google’s usual strengths: people, tools, capabilities, and reputation. I proposed a three-pronged effort consisting of immediately impactful fusion research, a long shot focusing on an “out there” goal, and innovation advocacy in Washington, D.C. Some years later, we added sponsored research into the cutting-edge field of nuclear excitation. The NERD effort, started 10 years ago, is still bearing fruit today.

These programs all came from a question that I asked anybody who would listen: What can Google do to accelerate the future of nuclear energy?

Google’s Work on Fusion

The first research effort came from a proposal by my colleagueTed Baltz, a senior Google engineer, who wanted to bring the company’s computer-science expertise to fusion experiments atTAE Technologies in Foothill Ranch, Calif. He believed machine learning could improve plasma performance for fusion.

In 2014, TAE was experimenting with a warehouse-size plasma machine called C-2U. This machine heated hydrogen gas to over a million degrees Celsius and created two rings of plasma, which were slammed together at a speed of more than 960,000 kilometers per hour. Powerful magnets compressed the combined plasma rings, with the goal of fusing the hydrogen and producing energy. The challenge for TAE, as for all other companies trying to build commercial fusion reactors, was how to heat, contain, and control the plasma long enough to achieve real energy output, without damaging its machine.

Google collaborated with the fusion company TAE Technologies to improve the performance of the plasma within its C-2U machine. The goal was to keep the plasma stable and drive it to fusion conditions. TAE Technologies

The TAE reactor could fire a “shot” about every 10 minutes, each of which lasted about 10 milliseconds and produced a treasure trove of data. There were more than 100 settings that could be adjusted between shots, including parameters like the timing and energy of plasma-formation pulses and how the magnets were controlled. Baltz realized that TAE’s researchers had an engineering-optimization problem: Which knobs and switches should they fiddle with to learn, as quickly as possible, the best ways to keep their plasma steady and drive it to fusion conditions?

To contain, squeeze, and shape the plasma, TAE developed a special way of using magnetic fields, called afield-reversed configuration. This implementation was predicted to become more stable as the energy went up—an advantage over other methods, in which plasmas get harder to control as you heat them. But TAE needed to do the experiments to confirm that those predictions were correct.

To help them figure out which settings to try for each new shot, Baltz and his team developed theoptometrist algorithm. Just like when you’re at the eye doctor and the optometrist flips lenses, saying, “Can you see more clearly with A or B?,” the algorithm presents a human operator with a pair of recent experimental outcomes. That human, who is an expert plasma physicist, then chooses which experiment to riff on with further parameter tweaks.

This was machine learning and human expertise at their best. The algorithm searched through thousands of options, and humans made the call. With the help of the optometrist algorithm, TAE achieved the longest-lived plasmas of that experimental campaign. The algorithm also identified a set of parameters that surprised physicists bycausing plasma temperatures to rise after the initial blast.

With the help of Google’s algorithms, TAE’s Norman machine achieved higher plasma temperatures than expected: 75 million °C. Erik Lucero

The collaboration continued with TAE’s next machine, Norman, which achieved even higher plasma temperatures than TAE’s original goal. The Google team also created algorithms toinfer the evolving shape of the plasma over time from multiple indirect measurements, helping TAE understand how the plasma changed over the life of a shot. TAE is now building a new and bigger machine calledCopernicus, with a goal of achieving energy breakeven: the point at which the energy released from a fusion reaction is equal to the amount of energy needed to heat the plasma.

A nice side benefit from our multiyear collaboration with TAE was that people within the company—engineers and executives—became knowledgeable about fusion. And that resulted in Alphabet investing in two fusion companies in 2021, TAE and Commonwealth Fusion Systems. By then, my colleagues at Google DeepMind were also using deep reinforcement learning for plasma control within tokamak fusion reactors.

Low-Energy Nuclear Reactions

NERD’s out-there pursuit was low-energy nuclear reactions (LENR)—still popularly known ascold fusion. This research field was so thoroughly lambasted in the early 1990s that it was effectively off-limits for decades.

The saga of cold fusion goes back to 1989, when electrochemistsMartin Fleischmann and B. Stanley Pons claimed that electrochemical cells operating near room temperature were producing excess heat that they said could only be explained by “cold fusion”—reactions that didn’t require the enormous temperatures and high pressures of typical fusion reactions. Their rushed announcement created a media circus, and when hasty attempts to replicate their results were unsuccessful, the discrediting of their claims was rapid and vehement. Decades later, there had been no confirmations in credible peer-reviewed journals. So, case closed.

Or perhaps not. In the early 2010s, an Italian entrepreneur namedAndrea Rossi was getting some press for a low-energy nuclear device he called an energy catalyzer, or E-Cat. Googlers tend to be curious, and a few of us took skeptical interest in this development. I’d already been discussing LENR withMatt Trevithick, a venture capitalist whom I’d met at the premiere of Pandora’s Promise, in 2013. He had an interesting idea: What would happen if a fresh group of reputable scientists investigated the circumstances under which cold fusion had been hypothesized to exist? Google could provide the necessary resources and creative freedom for teams of external experts to do objective research and could also provide cover. Trevithick’s proposal was the second pillar of NERD.

During Google-sponsored work on low-energy nuclear reactions, one group used pulsed plasma to drive hydrogen ions toward a palladium wire target. The researchers didn’t detect the fusion by-products they were looking for. Thomas Schenkel

Trevithick had been scouting for scientists who were open to the idea that unusual states of solid matter could lead to cold fusion. Google greenlit the program and recruited Trevithick to lead it, and we ended up funding about 12 projects that involved some 30 researchers. During these investigations, we hoped the researchers might find credible evidence of an anomaly, such as distinct and unexplainable thermal spikes or evidence of nuclear activity beyond the error bars of the measurement apparatus. The stretch goal was to develop a reference experiment: an experimental protocol that could consistently reproduce the anomaly. Our commitment to publish whatever we learned, including findings that supported simpler non-nuclear explanations, established an expectation of scientific rigor that motivated our academic collaborators.

The group had great morale and communication, with quarterly in-person check-ins for the principal investigators to compare notes, and annual retreats for the academic research teams. This was some of the most fun I’ve ever had with a scientific group. The principal investigators and students were smart and inquisitive, their labs had expertise in building things, and everyone was genuinely curious about the experiments being designed and performed.

Google’s sponsorship of research on low-energy nuclear reactions has led to continued work in the field. At Lawrence Berkeley National Laboratory, researchers are still experimenting with pulsed plasma and palladium wires. Marilyn Chung/Lawrence Berkeley National Laboratory

During the four-year duration of the program (from 2015 to 2018), our sponsored researchers did not find credible evidence of anomalies associated with cold fusion. However, everyone involved had a positive experience with the work and the rigorous way in which it was done. The program yielded28 peer-reviewed publications, the crown jewel of which was “Revisiting the Cold Case of Cold Fusion,” in 2019. In this Nature article, we described our program’s motivations and results and showed that solid scientific research in this area can yield peer-reviewed papers.

The project ratified a longstanding belief of mine: that credible scientists should not be discouraged from doing research on unfashionable topics, because good science deepens our understanding of the world and can lead to unanticipated applications. For example, Google-funded experiments performed at the University of British Columbia later led to the discovery of anew way to make deuterated drugs, in which one or more hydrogen atoms is replaced with the heavier hydrogen isotopedeuterium. Such drugs can be effective at lower doses, potentially with reduced side effects.

Despite not obtaining reliable evidence for cold fusion, we consider the project a success. In October 2021, Trevithick was invited topresent at a workshop on low-energy nuclear reactions hosted by the Advanced Research Projects Agency–Energy. In September 2022, ARPA-E announced that it would spend up to US $10 million to investigate LENR as an exploratory topic. The ARPA-Eannouncement mentioned that it was building on recent advances in “LENR-relevant state-of-the-art capabilities and methodologies,” including those sponsored by Google and published in Nature.

Nuclear Advocacy in Washington

A challenge as large as creating a new nuclear energy industry is beyond what any single company can do; a supportive policy environment is critical. Could Google help make that happen? We set out to answer that question as the third NERD effort. A year after meeting at the premiere of Pandora’s Promise, climate philanthropistRachel Pritzker, venture capitalistRay Rothrock, and some Googlers gathered at Google to discuss next steps. Pritzker suggested that we partner withThird Way, a think tank based in Washington, D.C., to see if there was a feasible path to policy that would accelerate innovation inadvanced nuclear energy. By advanced nuclear, we were primarily talking about new reactor designs that differ from today’s typicalwater-cooled fission reactors.

Advanced reactors can offer improvements in safety, efficiency, waste management, and proliferation resistance—but because they’re new, they’re unlikely to succeed commercially without supportive government policies. Third Way’s analysts had found that, even in these highly partisan times, advanced nuclear was nonpartisan, and they believed that an opportunity existed to push for new legislation.

At the time, the only framework that the U.S. Nuclear Regulatory Commission (NRC) had for approving commercial reactor designs was based on light-water reactors, technology dating from the 1950s. This was exasperating for innovators and investors and created unnecessary hurdles before new technologies could get to market. For advanced nuclear energy to move forward, policy change was needed.

Seven bills were signed into law by three presidents, including bills to fund the demonstration of new reactor designs and to compel the NRC to modernize its licensing procedures.

Third Way helped organize a meeting at the White House Executive Office Building in June 2015 on the topic of advanced nuclear energy. This meeting was an amazing gathering of about 60 representatives from the Department of Energy, National Nuclear Security Administration, NRC, National Security Agency, State Department, and Senate. Many spoke passionately about their concern that the United States had ceded leadership in advanced nuclear. People in many branches of the U.S. government wanted to change this situation through new policy. We listened.

In 2015, Google supported Third Way and another advocacy organization, theClean Air Task Force, to start working with legislators to craft bills that promoted innovation in nuclear energy. That same year, the Gateway for Advanced Innovation in Nuclear Act (GAIN) was passed, which connected nuclear developers with the U.S. national labs and their vast R&D capabilities. The initial two groups were soon joined by another advocacy group, ClearPath; eventually more than a dozen organizations were involved, representing the entire spectrum of political ideologies. They in turn engaged with industrial labor unions, advanced nuclear developers, and potential electricity purchasers like Amazon, Dow Chemical, and Microsoft. As an advisor to Third Way, I got invited to meetings in D.C., where people appreciated hearing my outsider and Silicon Valley perspective on innovation.

Thisadvanced nuclear policy campaign shows how the U.S. government became a partner in enabling private-sector innovation in nuclear technology; it also cemented nuclear innovation as one of the most nonpartisan issues in Washington. Starting in 2015, seven bills were signed into law by three presidents, including bills to fund the demonstration of new reactor designs and to compel the NRC to modernize its licensing procedures. In one welcome development, the NRC ruled that new fusion reactors will be regulated under different statutes than today’s fission reactors.

Today, the U.S. federal government is providing more than $2.5 billion to help developers build the first advanced reactors, and $2.7 billion to produce the new forms of nuclear fuel required by most advanced reactors. Many advanced nuclear companies have benefited, and recently Google signed the world’s first corporate agreement to purchase nuclear energy from multiple small modular reactors (SMRs), to be developed by Kairos Power.

Contrary to what you might see in the press about stalemates in D.C., my brush with policy left me optimistic. I found people on both sides of the aisle who cared about the issue and worked to create meaningful positive change.

The Possibility of Designer Nuclear Reactions

In 2018, Google’s funding of cold fusion was winding down. My manager, John Platt, asked me: What should we do next? I wondered if it might be possible to create designer nuclear reactions—ones that affected only specific atoms, extracting energy and creating only harmless by-products. As I surveyed the cutting edge of nuclear science, I saw that advances in nuclear excitation might offer such a possibility.

Nuclearexcitation is the phenomenon in which the nucleus inside an atom transitions to a different energy state, changing the possibilities for its decay. I was intrigued by a brand-newpaper from Argonne National Laboratory, in Tennessee, about experimental observation of nuclear excitation by electron capture, which the researchers achieved by slamming molybdenum atoms into lead at high speed. Soon after that, scientists at EPFL in Switzerlandproposed a scientifically provocative approach to achieving nuclear excitation with a tabletop laser and electron accelerator setup that, under the right circumstances, might also allow exact control of the end products. I wanted to find out what could be done with this type of excitation technology.

After speaking with researchers at those institutions, I met withLee Bernstein, the head of the nuclear data group at the University of California, Berkeley. He offered an idea for a related experiment that had been sitting on the shelf for 20 years. He wanted to see if he could use high-energy electrons to excite the nucleus of the radioactive element americium, a component of nuclear waste, potentially transmuting it into something more benign. I was deeply intrigued. These conversations suggested two complementary paths to achieving nuclear excitation, and Google is funding academic research on both.

EPFL’s Fabrizio Carbone is exploring the low-energy path to nuclear excitation. His group plans to use vortex beams of electrons to excite nuclei and release energy. Simone Gargiulo/EFPL

EPFL’sFabrizio Carbone is exploring the low-energy path. His approach uses an ultrafast laser and precisely tailored electron pulses to excite specific nuclei, which should then undergo a desired transition. Carbone’s team first worked on the theoretical foundation for this work withAdriana Pálffy-Buß, now at the University of Würzburg, and then performed initial baseline experiments. The next experiments aim to excite gold nuclei using vortex beams of electrons, something not found in nature. This technique might be a route to compact power generation with designer nuclear reactions.

Bernstein is exploring the high-energy path, where high-energy electrons excite the nuclei of americium atoms, which should cause them to decay much faster and turn into less toxic end products. Bernstein’s original plan was to custom-build an apparatus, but during the COVID-19 pandemic he switched to a simpler approach using Lawrence Berkeley Laboratory’sBELLA laser facility. The flexibility of Google’s research funding allowed Bernstein’s team to pivot.

Still, it turns out you can’t easily get a sample of nuclear waste like americium; you have to work up to it. Bernstein’s first experiment showed that high-energy electrons and photons excited the nuclei of bromine atoms and created long-lived excited nuclear states, making the case for using americium-242 in the next experiment. In 2025, we should know if this approach offers a way to convert waste into a useful product, such as fuel for the nuclear generators used in space missions. If successful, this process could deal with the americium that is the most dangerous and long-lived component of spent reactor fuel.

Solid science can have good side effects. Bernstein’s work attracted the attention of DARPA, which is nowfunding his lab to apply his excitation technique for a different application: creating actinium-225, a rare and short-lived radioactive isotope used in highly targeted cancer therapy.

Nuclear Energy Could Be a Big Win for Climate

When it comes to tackling climate change, some people advocate for putting all our resources into technologies that are fairly mature today. This strategy of “playing not to lose” makes sense if you have a good chance of winning. But this strategy doesn’t work in climate, because the odds of winning with today’s technologies are not in our favor. The Intergovernmental Panel on Climate Change (IPCC) has reported that business-as-usual emissions put our planet on a path to more than 2 °C of warming. In climate, humankind needs to use the strategy of “playing to win.” Humanity needs to place many big and audacious bets on game-changing technologies—ones that decrease energy costs so much that in the long run, their adoption is economically and politically sustainable.

With luck, hard work, and allies, the program’s successes have been more than we expected.

I’m proud of Google for placing bets across the near-term and long-term spectrum, including those made through our NERD program, which showed how the company could help advance nuclear energy R&D. Our projects addressed these questions: why this research, why these people, why now, and why Google? I’m grateful to my managers in Google’s energy research division for their support of exploratory research and innovation-friendly policy advocacy, and I appreciate my colleagues in the larger Google ecosystem who are working toward similar goals. With luck, hard work, and allies, the program’s successes have been more than we expected. In one form or another, these efforts have grown and strengthened through other people’s ongoing work and through diversified funding.

I never would have guessed that a couple of chance discussions at the premiere of Pandora’s Promise would have delivered 10 of the most energizing years of my career. The hard work and dedication I’ve observed gives me confidence that better energy sources will be developed that can pull a billion people out of energy poverty and help our energy systems decarbonize. And one big win in nuclear energy could make all the difference.