During the summer of 2016 articles from our growing archive will be republished. This one was first published in September 2012.

Nuclear power is both a promising and problematic energy source. On the one hand, nuclear power continuously generates large amounts of energy without consuming fuels that contribute to global warming. On the other hand, there are concerns about nuclear accidents and the storage of spent radioactive material. The Royal Swedish Academy of Engineering Sciences, or IVA, and the Royal Swedish Academy of Sciences have found a number of future technologies that may improve nuclear power. One of them is to use thorium as fuel.

An untapped source of energy

Thorium is not strictly a renewable energy source. The element, which was discovered in the early 1800s by the Swedish chemist Jons Jakob Berzelius, has been around for eons.

A large part of the heat generated in the earth’s core actually comes from nuclear processes involving thorium. But even if thorium is not renewable, it is estimated it to be 3-4 times more common than uranium. The issue is that found deposits have largely not yet been used.

Nuclear power plants generate large amounts of energy but create concerns about accidents and fuel storage

The advantages of thorium

According to the UN nuclear agency IAEA there are many benefits with thorium compared to uranium, which is currently used in nuclear reactors.

To begin with, there is limited radioactive debris when thorium is used. And in terms of chemical stability and resistance to radioactivity thorium is a safer alternative compared to uranium.

Depending on the core process utilized, thorium leads to more energy that can be recovered from this cheap, available and relatively safe energy.

One of the major drawbacks of nuclear power is the fear that countries that have the technology will use it to acquire nuclear weapons.

This is much more difficult to do with the material that is created in nuclear reactors fueled with thorium compared to those that run on uranium.

Investments in India and China

The obvious advantages of using thorium in core processes have been particularly interesting to India and China. Both countries have invested in a new generation of thorium-based nuclear power plants.

The Indian reactors Kakrapar-1 and Kakrapar-2 were the first in the world to use thorium on a large scale. Already in 1995, the reactors succeeded to operate 400 days at full strength based on thorium. India’s long-term interest in thorium is not just about its environmental benefits. India has only one percent of the world’s uranium resources, but about 30 percent of the world’s thorium resources. Canada, the U.S., Germany, UK and the Netherlands have also tested thorium as an alternative fuel.

Technical challenges to be solved

Although thorium can already be used, a number of technical challenges need to be resolved before this new technology can reach its full potential.

For example, higher temperatures are required to produce thorium-based fuels. Residual materials from thorium-based nuclear power lose their radioactivity faster than residual materials from uranium-based nuclear fuels. In the short term, however, thorium’s residual materials emit stronger radiation and this increases the cost of the immediate handling.

Will thorium replace uranium?

As experience is gained from thorium-based nuclear power plants, and from the research done in the field, we will most likely become aware of the pros and cons of this relatively new energy source.

Perhaps the biggest challenge when moving from uranium to thorium is the time and the investments that are required. Many countries, because of these high investment costs, cling to the uranium that is already used as a nuclear fuel. Given that thorium is regarded as a less dangerous, less expensive, more accessible and more environmentally friendly alternative to uranium, there are good reasons to keep an eye on developments.

The article was published in September 2012