China in its push to reduce its dependence on coal-fired power plants sees thorium liquid salt reactors (TMSRs) as an important step in developing clean energy technology. Not only will they provide electrical power, but also will provide hydrogen, methanol and other byproducts. China has had trouble getting its first TMSR up and running but they remain the leader at this moment, ahead of planned projects in France and India (the latter country is experimenting with solid thorium-fueled water-cooled reactors). The U.S. developed a prototype in the 1960s but shelved it. But now China is in the forefront with a target completion date of 2020. Westinghouse is advising on the project.
Thorium (seen below) is a radioactive element. It is widely abundant in the Earth’s crust. Its radioactive half-life is much shorter than uranium or plutonium. And its byproducts are of no value for making nuclear weapons.
What are the advantages of thorium reactors and particularly thorium molten salt?
- Thorium is far more abundant than uranium and plutonium.
- A TMSR can harness up to 98% of the energy from the fuel it burns. Compare that to current reactors which obtain efficiencies of between 2 and 5% in a given volume of plutonium or uranium.
- The molten salt is liquid which expands when heated. This slows the nuclear reaction and creates a much safer technology than traditional fuel rod reactors.
- The reactor is self-governing with a drain with plug at the bottom of each molten salt container. Should something go wrong the plug melts and the molten salt drains into a shielded underground container.
- Molten salt reactors are not limited to burning thorium. They can consumer different nuclear fuels including nuclear fuel waste and use it as an energy source. That makes them highly attractive as a means of consuming spent uranium and plutonium from existing reactors. And the small part of the fuel residue from TMSRs is Plutonium 238, used by NASA for Deep Space Missions as a heat and energy source for missions like Cassini or the Mars rover, Curiosity.
- Another byproduct is Molybdenum 99 used in medical diagnostics. Currently the source of such radioactive diagnostic imaging materials has been compromised by a worldwide shortage when Canada’s Chalk River nuclear reactor sprung a leak and subsequently, the country decided to phase it out of operation.
Thorium has been called a super fuel by writers such as Richard Martin who recently published a book by that same name. In it Martin argues that using thorium fuel in existing reactor technology would be far safer than the fuels we use today. He states that the only reason most of the world uses uranium and plutonium dates back to the beginning of atomic weapons programs in the 1940s. He blames the military for the aborted thorium prototype shelved by the U.S. in the 1960s.
The fact that China has taken the lead in building the first TMSR speaks to the reality that country faces as it deals with its growing energy demand. The Chinese have shut down conventional nuclear power plant projects and scaled back their plans because of obvious concerns with safety issues brought to light by the disaster at Fukushima, Japan, following the 2011 earthquake and tsunami.
At the 2012 Thorium Energy Conference held in late October of this year in Shanghai, the son of China’s former president, Jiang Zemin, Jiang Mianheng, spoke at length about why the country is focused on TMSR technology. He is the president of the Chinese Academy of Sciences in Shanghai, and sees TMSRs as a way for China to reduce greenhouse gas emissions while meeting its future energy needs.
To learn more about thorium reactors visit the International Thorium Energy Organisation on the web.