With only a few months remaining out of a five-year qualification programme by Thor Energy in Norway, the commercialisation of thorium as a fuel in conventional nuclear reactors is imminent.

Initiated by The Thorium Irradiation Consortium, it is led by Thor Energy and has the Institute for Energy Technology (IFE) in Norway; Westinghouse; Fortum in Finland; the UK’s National Nuclear Laboratory; the German Institute for Transuranic Elements (ITU); and the Korea Atomic Energy Research Institute (KAERI) as consortium partners.

Three countries, China, India and Turkey, have so far declared thorium as part of their national power policy and the OECD-NEA recently published a paper concluding that the implementation of thorium as a nuclear fuel is sensible, safe and reasonable in the long run, and that this evolution starts with combined uranium and thorium cycles in the near term.

The US, France, Japan, China and South Korea have the most uranium-based nuclear reactors. These are all potential clients for the thorium/uranium pellet fuel. South Korea has 24 uranium-based nuclear reactors, each the size of Koeberg, which represents enormous potential for the new thorium-containing pellet fuels.

Thorium fuel can use either uranium or plutonium as the fissile driver material. The waste produced by the thorium fuel cycle is safer than the waste produced by the uranium fuel that is currently used in existing nuclear reactors. Thorium is environmentally safer and extremely difficult to use to make a nuclear weapon.

The thorium fuel cycle is cleaner than that of uranium. In contrast, uranium produces plutonium and minor actinides in its waste, and plutonium can be used to manufacture a nuclear weapon. These minor actinides remain radioactive for thousands of years. The thorium fuel cycle produces no plutonium and hardly any minor actinides.

In contrast, the waste from the thorium fuel cycle contains mainly fission products that lose most of their radioactivity in a short time period. As a result, the thorium fuel cycle would substantially reduce the problems associated with the management and storage of nuclear waste.

The first thorium fuel specimens were loaded into the Norwegian fuel-testing reactor operated by the Institute for Energy Technology in Halden in April 2013, and the second round loaded before Christmas 2015, was intended to verify test results.

“With this second rig loaded, we have reached a major milestone and an important stepping stone towards commercial approval for thorium in existing light water reactors (LWRs),” said Oystein Asphjell, CEO of Thor Energy.

“This rig represents a further step in the thorium evolution which will contribute towards the long-term sustainability of nuclear power in general and specifically for thorium as an additive and improvement to the uranium fuel cycle,” he said.

This second phase of the thorium irradiation consists of 12 fuel pins in a new, fully-instrumented test fuel rig. It consists of three variants of ThAdd fuel, which are uranium-based pins with small fractions of thorium, four reference pins as well as two pins with Accident Tolerant Fuel from Korea Atomic Energy Research Institute, KAERI.

“The irradiation will produce a great deal of unique data from a number of parameters that describes how the fuel ceramic behaves as it operates for long periods in a reactor core in various conditions.”

“The Halden test reactor allows for continuous data collection while the fuel operates in the reactor. The data acquired is necessary to confirm that the fuel could be implemented safely and productively in a commercial reactor and will support computer modelling efforts and the planning for follow-on testing in a commercial power reactor,” he said.

“Thorium oxide-based fuels can provide advantages such as higher thermal conductivity and a higher melting point – properties that have safety margin benefits. Thorium fuels also generate no new plutonium,” said Trevor Blench, chairman of the Steenkampskraal Holdings, owners of the mine in Western Cape which plans to supply thorium to the nuclear fuel industry.

The Steenkampskraal thorium and rare earth mine hopes to begin mining in about 18 months. The mine has the world’s highest-grade rare earth and thorium deposit with average grades of 14.4% rare earths and 2.14% thorium.

“We see significant potential for thorium as a safe supplement to uranium as a nuclear fuel. The increasing demand for rare earths indicates that there is an immediate demand for the mine’s production,” he said.