A Swiss start-up strives to reinvent nuclear power

Nuclear energy currently produces about 10% of the electricity consumed in the world. Keystone/Giroscience/Science photo library

Transmutex is currently developing a new type of nuclear reactor using thorium instead of uranium. It could produce electricity more safely and without generating the famous highly radioactive waste. An innovation capable of facilitating the energy transition to a “zero emissions” society?

This content was posted on Feb 01, 2022 – 10:00 AM

“When a Nobel laureate asks you to work with him, it’s hard to say no.” Nuclear physicist Federico Carminati well remembers the call from Carlo Rubbia, then director of the European Organization for Nuclear Research (CERN), based in Geneva. “It was 1990 and I was a young CERN employee. Rubbia asked me to participate in the development of a new type of nuclear reactor.

“We have all the essentials to build a new type of reactor”

Federico Carminati, Transmutex

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A certain euphoria then surrounded the project, but the idea of ​​a thorium reactor coupled with a particle accelerator failed. Innovation is of little interest to the nuclear industry and the problem of radioactive waste and its storage does not present any urgency.

Thirty years later, times have changed. For Carminati, the time has come to relaunch the Rubbia project. In 2019, he founded the start-up Transmutexexternal link with French businessman Franklin Servan-Schreiber. Its objective: to “reinvent” nuclear energy based on its principles.

Thorium instead of uranium

Atomic power plants produce electricity using the heat generated by nuclear reactions. In a conventional reactor, neutrons collide with atoms of combustible material – usually uranium or plutonium. Atoms split (fission process), releasing energy and new neutrons, resulting in a chain reaction. The heat generated by fission is used to produce steam, which drives turbines that generate electricity.

>> The following short animation shows what happens during nuclear fission:

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An atomic power plant produces electricity continuously, in large quantities and without emitting greenhouse gases. But it generates radioactive waste that many countries, including Switzerland, still don’t know how to permanently store.

Transmutex’s solution is to replace uranium with thorium and combine the reactor with a particle accelerator. Thorium is a weakly radioactive metal present in abundance in rocks throughout most of the Earth’s crust. “It’s much more democratic than uranium,” says Federico Carminati. Most of the uranium used as nuclear fuel is in fact mined only from mines in Kazakhstan, Australia and Canada.

In the start-up solution, thorium is fissioned inside a reactor maintained in a subcritical state and fed with neutrons by a particle accelerator. This means that, unlike conventional installations, the plant prohibits any chain reaction. When the neutron flow is stopped, the reactor stops immediately. A function that would have prevented the Chernobyl disaster of 1986.

less waste

The advantages of a thorium reactor coupled to a particle accelerator are numerous, says Federico Carminati. Radioactive decay periods for thorium by-products are much shorter than for a uranium plant – 300 years compared to 300,000 years – and hazardous waste volumes are considerably reduced. “We are talking about a few kilograms instead of tons”, explains the nuclear physicist.

The thorium cycle would also have the advantage of preventing nuclear proliferation. According to Federico Carminati, its fission by-products cannot be used to make an atomic bomb.

Federico Carminati specializes in computer simulation of nuclear systems. transmutex

This is not everything. A thorium reactor can also be powered by waste from existing nuclear power plants. The flow of ultra-fast particles is able to burn these residues and produce energy. Following this “transmutation” process (hence Transmutex), part of the short-lived radioactive waste could be converted into stable elements. “Which would solve the problem of the accumulation and storage of highly radioactive waste”, notes Federico Carminati.

Collaboration with USA and Russia

Transmutex wants to explore technologies developed in Switzerland and abroad. Together with the Paul Scherrer Instituteexternal linkSwitzerland’s leading center for research in natural sciences and engineering, the start-up plans to build a particle accelerator more powerful than those currently used to treat cancer.

The company has also initiated collaborations with several international partners. The Russian national atomic energy company Rosatom is studying the possibility of developing the reactor, while the Argonne National Laboratory, one of the most important nuclear research laboratories in the United States, is working on the thorium fuel.

“We have all the essential elements to make a new type of reactor, just assemble them,” says Federico Carminati. Transmutex’s goal is to manufacture a demonstration prototype in the early 2030s.

Nuclear renaissance?

The omens look favorable for a new generation of nuclear power. Demand to reduce CO2 emissions and fears of prolonged power outages are reviving an option that Fukushima seemed to have buried.

Currently, about 440 nuclear power plants in operation in the world generate about 10% of the electricity consumed globally.

In several countries, work is advancing to build more compact, simpler, safer and cheaper nuclear reactors. US President Joe Biden has earmarked $2.5 billion for research and industrial application of advanced reactors. Also in the United States, the TerraPower company founded by Bill Gates is ready to build the first mini-sodium nuclear power plant, ahead of hundreds of others planned. In Chinaexternal link, the first thorium nuclear reactor is about to enter service. However, it will use a different technology than Transmutex.

The nuclear “renaissance” also affects the European continent. The EU Commission wants to include the atom, as well as natural gas, in the “green” sources that promote the energy transition. An approach supported by France, but contested by Germany, after Fukushima and its decision to close its nuclear plants.

Switzerland also opted for the gradual abandonment of the atom. Some figures in the bourgeois parties, however, are calling for a reconsideration of nuclear energy as part of the long-term energy strategy to avoid supply problems. Club Energie Suisse, a pro-nuclear association, does not rule out the launch of the popular initiative “Stop the blackout”. A text aimed at lifting the ban on building new nuclear power plants, approved by the Swiss people in 2017external link.

For cleaner electricity

“Having flexible, modular, small-scale technology to produce clean, safe energy in ten years would be fantastic,” says ETH Energy Science Center director Christian Schaffner. We need to electrify mobility and heating. And we need more electricity, which must be clean.”

However, the latter believes, it may take twenty years before a new plant is connected to the grid. “I don’t think we have that much time to deal with the climate emergency.” Another issue: the aspect of cost and profitability. Such a plant “could it be more economical than solar energy, which is currently cheaper than traditional nuclear energy?” asks Christian Schaffner. According to him, it would make more sense to make the most of existing facilities.

More critically, former nuclear safety and regulatory officials in the US, Britain, France and Germany argue that this energy should not be seen as a solution to the climate crisis. “Nuclear [y compris celui de nouvelle génération] it is neither clean nor safe nor intelligent, it is a very complex technology that can cause significant damage,” they say in a joint statement.external link.

At Transmutex, Federico Carminati is optimistic. “Some consider our project ambitious and complex. But nobody ever told us why it shouldn’t work.”

As it stands, the start-up has raised eight million francs, including five from US private investors. He estimates the cost of the pilot reactor at around SFr1.5 billion.

“It is an important project and if we are successful, we will make a fortune”, jokes Federico Carminati. If, on the other hand, the project fails, I have at least tried something I can be proud of.

This article was modified on February 22 to more accurately explain the nuclear fission process, in addition, the reference to the Russian company Rosatom was changed.

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