Thorium – the energy source of the future?
Thorium is a weakly radioactive, soft and ductile heavy metal. It is the most abundant radioactive element in the earth's crust and is often extracted from monazite. On earth, it is almost exclusively found as thorium-232; other isotopes are only present in trace amounts or are entirely synthetic. Since the 1960s, the focus has been on its experimental use in liquid salt reactors, where it is to replace uranium.
Aspects of energy production
Thorium reactors could be a fascinating alternative to conventional nuclear reactors. Would thorium be a better fuel than uranium or plutonium? Experts say they would produce less waste. However, developing the appropriate technologies is a significant challenge.
In a thorium reactor, the radioactive element thorium is used for nuclear fission and, thus, for energy production. This is said to improve the safety of nuclear power. Research and development work on thorium as an alternative to uranium has been ongoing internationally for some time. The demand for efficient energy generation is steadily increasing with the population growing. Thorium is a slightly radioactive metal mainly extracted from the mineral monazite. As a result, interest in thorium reactors has increased worldwide. For example, the Molten Salt Reactor Experiment (MSRE) in the USA was an early project. Likewise, India is working on extensive programmes to develop thorium reactors. It is known that China is investing heavily in this technology. Norway and Denmark are also involved.
In June 2023, China's Nuclear Safety Regulatory Commission granted an operating license for the country's first thorium reactor, marking a significant milestone.
Thorium reactor
In a thorium reactor, thorium-232 is used as the primary fuel. Neutron bombardment of thorium produces the fissile uranium-233, which maintains the chain reaction. It is a form of nuclear reactor in which the radioactive material thorium is used for atomic fission and, thus, for energy production. The result is less atomic waste and an increased potential for improving nuclear safety. The structure of a thorium reactor is comparable to that of a conventional nuclear reactor. However, thorium is used as fuel. The thorium reactor consists of a reactor pressure vessel, where atomic fuel and moderator, as well as control rods for regulating the reaction and coolant systems for heat dissipation, would be located. Due to the lower risk of core meltdown, thorium reactors are considered safer than conventional uranium reactors. Less radioactive waste is produced. The misuse of the thorium used to make weapons is said to be less likely because it is more complicated. However, radioactive contamination and technical failures cannot be ruled out entirely. The fact is that thorium reactors are a challenge in terms of technology and costs.
Thorium reactors and ‘mini-nuclear power plants’ are being discussed worldwide and in this country. Opinions are correspondingly controversial. The risks and disadvantages of liquid salt reactors are also pointed out.
If nuclear energy's comeback has remained an issue, environmental organisations point out incorrect claims. For example, no significant progress has been made in nuclear energy recently.
Challenges and disadvantages despite many advantages in the development and implementation of thorium reactors:
- The technology is not yet fully developed.
- The conversion from uranium to thorium reactors requires a great willingness to invest.
- Worldwide, only a few isolated thorium reactors are currently operational.
- A latent obstacle is the public perception and acceptance of nuclear energy.
Positive environmental aspects
- Thorium reactors can significantly reduce the environmental impact of energy production.
- Thorium reactors produce fewer greenhouse gases than fossil fuels.
- Less cooling water is needed than in conventional nuclear reactors.
- Thorium mining has less of an environmental impact than uranium mining.
- The smaller amount of waste from thorium reactors reduces the problem of final disposal.
- Thorium reactors could reduce global carbon emissions.