Cold fusion

Summary: Cold fusion is a hypothesis that posits nuclear fusion at room temperature to explain the results of various experiments. Although disputed and controversial following some exaggerated claims, the hypothesis continues to spark interest among scientists.

Cold fusion refers to a radiation-free form of fusion energy that, although much discussed, exists in theory only. The concept is not new among the scientific community, but it is one with which many scientists have been uncomfortable because of previous scandals associated with it.

Cold fusion theoretically provides a way to generate clean energy from uranium without incurring the harmful effects, including radiation, that come from traditional ways of generating a nuclear reaction. Although failed claims related to some researchers’ investigations into cold fusion have brought disrepute to the notion, developments periodically interest some scientists in cold fusion as a possible alternative energy source.

If cold fusion could prove to be practicable, or even possible, it could represent a limitless, cheap, and pollution-free source of energy. New and inexpensive measuring devices have reinvigorated the field, as these permit more laboratories to conduct cold fusion research. Additionally, findings indicate that cold fusion might occur naturally in certain bacteria, and some scientists have been excited by research that centered on a battery based on cold fusion. Despite this enthusiasm, a great deal of trepidation remains regarding cold fusion because of prior scandals and unsubstantiated claims regarding cold fusion discoveries and research.

Cold fusion received a great deal of media attention in 1989, when researchers Martin Fleishmann and Stanley Pons claimed they had achieved nuclear fusion at room temperature using a simple, inexpensive tabletop device. The small tabletop experiment involved electrolysis of heavy water on the surface of a palladium (Pd) electrode. Fleishmann and Pons hypothesized that the high compression ratio and mobility of deuterium that could be achieved within palladium metal using electrolysis might result in nuclear fusion. To investigate, they conducted electrolysis experiments using a palladium cathode and heavy water within a calorimeter, an insulated vessel designed to measure process heat.

Current was applied continuously for many weeks, with the heavy water being renewed at intervals. For most of the time, the power input to the cell was equal to the calculated power leaving the cell within measurement accuracy. They then decided to announce their findings. However, the wild excitement that greeted their news quickly dissipated when other scientists could not reproduce their results. Pons and Fleishmann eventually closed their laboratories and left for France to continue their research at a laboratory sponsored by Toyota Motor Corporation. That laboratory closed in 1998 without any success in achieving cold fusion, and the term itself fell into disrepute.

Immediately following 1990, attention given to cold fusion in the media and research conducted dropped precipitously. Many in the scientific community believe that cold fusion is impossible, or at least highly improbable. Cold fusion depends on a nuclear reaction occurring within a crystal structure, which is unlikely, because all nuclei are positively charged and as a result they strongly repel each other. Without a catalyst such as a muon, very high kinetic energy generally is needed to overcome this repulsion. Skeptics of cold fusion assert that those calculations that demonstrate increased heat are based on faulty assumptions.

For example, Fleishmann and Pons assumed in their experiments that the efficiency of electrolysis is nearly 100 percent. Other researchers have asserted that if hydrogen and oxygen recombine to a significant extent within the calorimeter, electrolysis is less efficient and that this might account for the excess heat sometimes attributed to cold fusion. Due to skepticism regarding cold fusion, the US Patent and Trademark Office consistently rejected patent applications for apparatuses alleging cold fusion on the grounds that such devices do not work. Indeed, the US Court of Appeals for the Federal Circuit, which hears many patent disputes, ruled in In reSwartz (232 F.3d 862, Fed. Cir. 2000) that a device alleging cold fusion can be rejected on its face as inoperable.

Since then, scientists’ interest in the idea of cold fusion has revived, and examinations have been undertaken with the goal of alleviating the need for inexpensive energy sources. d. Cold fusion is envisioned as a way to help reduce the amount of pollution that comes from making energy, since it represents a clean energy source. Cold fusion’s only by-product would be helium particles, which do not harm the environment. Cold fusion would also be much less expensive than producing the amount of oil people use on a daily basis.

Achieving Cold Fusion

The most expensive element needed for cold fusion, heavy water, costs about $1,000 per kilogram retail, despite its ubiquitous nature. Heavy water is expensive because a great deal of energy is required to separate it from ordinary water and because demand is limited, so new separation technologies have not been developed. However, a huge amount of energy can be derived from heavy water from a fusion reaction. Even at $1,000 per kilogram, heavy water would be thousands of times less expensive than oil. In a heavy water cold fusion economy, a fraction of a percentage of the fuel would have to be recycled to keep the heavy water separation plants working, whereas 7 percent of oil goes to refinery use and loss.

Proponents of cold fusion believe that, in order for the process to be successful, three conditions must be met. First, the cold fusion devices must be safe and nonpolluting to keep with the green goals that the process favors. Second, cold fusion generators, motors, heaters, and other devices must have high power density, so they can be roughly as compact as competing motors. Third and last, cold fusion must be transferrable to a wide range of uses, from devices such as thermoelectric pacemaker batteries to automobile, marine, and aerospace engines.

While such benefits are enticing, little evidence supports the proposition. Indeed, most projects that have purported to demonstrate cold fusion have ended in scandal, recriminations, and sanctions. In 2002, for example, nuclear engineer Rusi Taleyarkhan claimed to have observed a statistically significant increase in nuclear emissions of products that he attributed to cold fusion, which he termed bubble fusion. Taleyarkhan was a faculty member at Purdue University, prior to which he was a staff scientist at the Oak Ridge National Laboratory. He alleged that he had observed fusion reactions during acoustic cavitation experiments with chilled acetone bombarded with deuterium.

Although Taleyarkhan published several papers outlining his results, other scientists working independently were not able to replicate his work. After a series of disputes, Purdue began an investigation regarding Taleyarkhan’s claims, which resulted in his being judged guilty of research misconduct for falsification of the research record. Despite this, the National Science Foundation provided Taleyarkhan with $185,000 in research funds to investigate bubble fusion.

In 2023, the US Advanced Research Projects Agency-Energy (ARPA-E) provided grants for "low-energy nuclear reactions" (LENR), another name for cold fusion. Although cold fusion was still unproven, some scientists continued to research it, including physicists at the National Ignition Facility in California who announced in December 2022 that a controlled nuclear fusion reaction had produced more energy that had been used to trigger it. Most experts said nuclear fusion was not likely to provide energy on a large scale before 2050.

The tantalizing potential benefits of cold fusion permit it to remain of interest to some, especially those who desire inexpensive, green energy. Despite ongoing research regarding cold fusion, however, little progress has been made. It appears that cold fusion will remain a tantalizing possibility for the foreseeable future.

Bibliography

Ball, Philip. "What Is the Future of Fusion Energy?" Scientific American, 1 June 2023, www.scientificamerican.com/article/what-is-the-future-of-fusion-energy/. Accessed 2 Aug. 2024.

Huizenga, J. R. Cold Fusion: The Science Fiasco of the Century. New York: Oxford University Press, 1994.

Mallove, E. J. Fire and Ice: Searching for Truth Behind the Cold Fusion Furor. Oxford: John Wiley & Sons, 1991.

Rao, Rahul. "Cold Fusion Is Making a Scientific Comeback." Popular Science, 3 July 2023, www.popsci.com/science/cold-fusion-low-energy-nuclear-reaction/. Accessed 2 Aug. 2024.

Taubes, G. Bad Science: The Short Life and Weird Times of Cold Fusion. New York: Random House, 1993.