More than 130 experimental nuclear fusion reactors, both public and private, are in operation, being built, or planned in 50 countries across the globe, according to a December 2022 report by the International Atomic Energy Agency (IAEA). About 90 are in operation, most of them tokamaks or stellarators, which use forms of magnetic confinement to heat and compress plasma in an effort to achieve nuclear fusion. In addition to the National Ignition Facility (NIF) in California, only five other facilities, all of which are smaller than the American lab, currently use laser beams to study this type of reaction: one in France, one in the UK, two in Japan, and another in the USA.
Brazil is the only country in the Southern Hemisphere with fusion reactors—the country has three small tokamaks (Australia plans to build a device, but using laser technology to stimulate the reaction). The largest in Brazil is the TCABR, located at the Physics Institute of the University of São Paulo (IF-USP). It was originally built by the École Polytechnique Fédérale de Lausanne, Switzerland, where it operated between 1980 and 1992. The plasma reactor was reassembled in Brazil and has been operating since 1999, undergoing periodic updates. “The plasma in a tokamak is subject to constant instability and this type of reactor needs regular maintenance,” explains physicist José Helder Facundo Severo, head of IF-USP’s Plasma Physics Laboratory.
Another tokamak, the ETE, is located at the Brazilian National Institute for Space Research (INPE), which designed and built a spherical machine whose geometry is slightly different to the other two reactors in the country. It has been operational since the year 2000. A third tokamak called Nova, manufactured in Japan in the 1980s, was relocated to the Federal University of Espírito Santo (UFES) at the end of 2020. The machine previously belonged to the University of Campinas (UNICAMP) and the Federal University of Rio Grande (FURG) before moving to UFES. “The tokamak has been assembled and is already functioning,” says UFES physicist Alfredo Cunha. “Now we are making improvements to the plasma positioning measurement system to better control it.”
Brazilian physicists say that the country once played a major role in nuclear fusion, but in recent decades the field has gone through various ups and downs and lost several researchers. Gustavo Canal, another physicist from IF-USP, led a proposal to create a national nuclear fusion program with the aim of revitalizing the sector, presented to Brazil’s National Nuclear Energy Commission (CNEN) and the Brazilian Ministry of Science, Technology, and Innovation (MCTI) in late 2021. Some of the ideas not implemented included the creation of a national nuclear fusion laboratory to coordinate and conduct activities in the area, and the modernization of devices currently used in the country.
“In recent years there have been major advances in high-temperature superconductors, which can be used to build smaller, more efficient, cheaper tokamaks,” says Canal. “It is no longer necessary to invest in such grandiose and expensive facilities.” According to the USP physicist, this new approach could provide an accelerated route to nuclear fusion. In other countries, private capital has been attracted to the field, which could be an alternative source of clean energy if commercial exploitation becomes viable. Major multinationals, such as oil company Chevron and Alphabet, which owns Google, have invested a total of around US$3 billion in nuclear fusion startups.
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