The below was co-authored by all contributors listed above, written from the perspective of Professor Berlinguette.
In a recent Nature paper, we describe the Thunderbird Reactor: a bench-top apparatus that generates deuterium–deuterium (D–D) fusion within a palladium metal target. The reactor loads deuterium fuel into one side of the target using plasma-immersion ion implantation (PIII) to enable fusion, and can increase reaction rates by 15% when using an electrochemical cell to load the other side of the target with more fuel. The Thunderbird Reactor is not an energy-generating device, but rather it serves as a platform for investigating different approaches to enhancing nuclear fusion reaction rates.
Where we started
For the uninitiated, “cold fusion” first gained global attention in 1989, when researchers claimed that electrolysis of heavy water with a palladium electrode produced excess heat, suggesting nuclear fusion at room temperature. The media coverage was immediate and widespread. However, subsequent attempts to reproduce the results failed, and independent reviews concluded the claims lacked sufficient evidence. Within months, a U.S. Department of Energy panel recommended against further funding. “Cold fusion” became a cautionary tale in scientific overreach and was effectively disqualified from mainstream research.
My experience in the fusion field began in 2015 when my program at the University of British Columbia (UBC) in Canada was invited to join a “peer group” convened by Google. At its peak, this group consisted of approximately 30 scientists across multiple institutions (UBC, MIT, the University of Maryland, Lawrence Berkeley National Laboratory). I was motivated to join this effort because our society urgently needs a transformational clean energy solution, and traditional funding models provide scientists with little-to-no opportunities to go out and do high-risk, potentially high-reward, research required to realize such innovations. That is what excited me about the opportunity to work with Google—they provided a safe environment for us to take some long shots.
Our peer group sought to address the question: was cold fusion prematurely dismissed?
Our aim was not to validate past claims, but to generate current and credible experimental data. The plan was to conduct a few years of focused research, maintain a low profile to minimize distractions, and publish the results only after robust internal scrutiny.
In 2019, we went public with our efforts via a Nature Perspective: “Revisiting the Cold Case of Cold Fusion”. We described our investigations, which found no evidence to support cold fusion claims. However, it was apparent to us that there was (and still is) a lack of reproducible and accessible data in this field. Creation of the conditions under which cold fusion is hypothesized to exist is very challenging, and such conditions have still not been credibly realized and thoroughly investigated. That leaves open the possibility that the dismissal of cold fusion may have been premature. Continued scepticism is justified, but we concluded our Perspective with the contention that more work is needed. As Matt Trevithick, then Senior Program Manager at Google Research, phrased it when reflecting upon the peer group’s work: What we learned enabled us to ask better questions, and we are now more secure in our ability to design rigorous experiments in this field.
Low-energy nuclear reactions (LENR) research has since been re-admitted to mainstream science. For example, in 2022 the U.S. Department of Energy’s Advanced Research Projects Agency (ARPA-E) funded a $10 million exploratory program on this topic. Within my lab at UBC, we secured funding from the Canadian federal government from 2020 to 2022 to support our fusion research. To my knowledge, this was the first time the Canadian government funded LENR research in the last 30 years. A gift from the Thistledown Foundation in 2022 enabled us pursue an even more focused hypothesis: Electrochemical loading of a palladium target with deuterium can increase nuclear fusion reaction rates.
What we built: The Thunderbird Reactor
Our team designed and built the Thunderbird Reactor to test our new hypothesis.
The Thunderbird Reactor generates D–D fusion reactions within a palladium target. Neutrons, products of D–D fusion, are detected to quantify fusion rates.
The Thunderbird Reactor enables us to control deuterium fuel density within the target, and observe how changes in electrochemical loading—achieved at electronvolt energy scales—influence nuclear interactions at megaelectronvolt scales. The reactor has two methods for delivering deuterium fuel into the target:
- PIII: Fuel delivery by a plasma thruster through a vacuum chamber, with a power supply accelerating the fuel into the target.
- Electrochemical loading: Fuel delivery by an electrochemical cell that sources additional fuel from the electrolysis of deuterated water (D2O).
PIII is used as a surface modification technique across several industries (e.g., semiconductors, medical implants, wear-resistant coatings). First author Dr. Kuo-Yi Chen had the idea to leverage PIII in the Thunderbird Reactor, which enabled the first demonstration of PIII-induced D–D fusion.
The Thunderbird Reactor’s electrochemical cell was inspired by my program’s work developing a membrane reactor for hydrogenation chemistry (e.g., Nat. Catal., 2018), which in turn was a result of our peer group work investigating how hydrogen enters and exits palladium films (e.g., Nat. Mater., 2019; Behind the Paper, 2020).
What we found: Electrochemistry can increase in fusion rates
When fuelled using only PIII, neutrons were detected at an increasing rate before reaching a plateau. Neutron production increased by 15% when the target was loaded with fuel by the electrochemical cell in addition to PIII.
To our knowledge, this is the first-ever reproducible demonstration of electrochemically loading a metal to increase nuclear fusion reaction rates.
The Thunderbird Reactor is not designed to be an energy-generating device. Rather, it serves as a new tool for probing nuclear reactions in condensed matter systems, and raises multiple avenues for future research across a range of fields, such as:
- Materials science: Explore alternative materials such as niobium or titanium, which may support higher deuterium loading and greater fusion activity;
- Nuclear fusion science: Increase ion flux using inductively coupled plasma sources to achieve higher reaction rates;
- Quantum information science: Test theoretical predictions involving quantum coherence or screening effects in metal lattices.
The Thunderbird Reactor offers a bridge between disciplines. We hope our work encourages other researchers in plasma physics, materials science, and electrochemistry to explore this vast, interdisciplinary space. As a community we can expand the knowledge base that low-energy nuclear reactions need—not just with claims, but with tools that invite deeper exploration.