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| Fig. 1: Comparison of fuel and waste quantities for a 1GW LWR and 1GW LFTR. (Source: Wikimedia Commons) |
According to the nation's 12th Five-Year Plan, China is looking to actively pursue new and renewable energy sources to power the country's future. Nuclear energy developments, although initially slowed by the events of Fukushima, are advancing to become a major player in China's energy portfolio. Currently, 40 gigawatts of conventional nuclear reactors (reduced from the original target of 50 gigawatts) have been approved to be built in China by 2015 with many additional plans in the pipeline. [1] However, conventional nuclear technologies pose many challenges in China including waste storage and uranium reserve depletion. Due to these challenges, China's interest in nuclear energy is shifting towards the new generation of +thorium reactors that promises to produce less nuclear waste while using a more abundant fuel source. This technology, once developed and utilized, could be the answer to China's search for clean, safe, and cheap energy.
In a thorium-fueled reaction, Th-232 is a fertile material that transmutes to the fissionable uranium isotope U-233 through the absorption of neutrons. Th-232 is a naturally abundant isotope of thorium and its conversion can lead to large amounts of fissile material that is several times the abundance of uranium naturally found on Earth. [2] China, which has the world's second largest thorium reserve, reportedly has enough thorium for 20,000 years. [3,4] The development of thorium technology could mean that the country, with less than 1% of all uranium resources in the world, will no longer have to rely as heavily on its current sizeable imports of uranium. [3]
In order for China to develop a long-term sustainable nuclear power program, it needs a waste management strategy. Currently, China only has a relatively low quantity of nuclear waste due to the small scale of its nuclear energy projects. [3] As nuclear developments increase in China to meet the rising electricity demand, nuclear waste disposal will become a more pressing issue. Using thorium in a liquid fluoride thorium reactor has a crucial advantage in that thorium fuel cycles produce less long-living transuranic elements thus minimizing the nuclear waste issue. Compared to the uranium/plutonium fuel cycle, it takes more neutron captures to form the transuranic elements in the thorium/uranium fuel cycle. In terms of the fission products produced, 83% of it can be removed from thorium-fueled molten salt reactor and become inert within a decade. The remaining 17% will require safe storage for 300 years. [5] The difference in the amount of waste generated for the liquid fluoride thorium reactors (LFTR) compared to the conventional light water reactors (LWR) in generating a comparable amount of electricity is highlighted in Fig. 1.
The technology for molten salt reactors using thorium already exists from research done at Oak Ridge National Laboratory in the 1960s. However, at that time plutonium products from uranium were needed to build nuclear bombs during the Cold War period and the technology was set aside. Now China's National Academy of Sciences is actively pursuing the development of thorium technology by using the designs which originated from the Oak Ridge National Laboratory to build a 2 MW LFTR by the end of 2020. The academy plans to then scale up the design and make it commercially viable in the next decade. [4] The demonstrated success of thorium technology in China will not only change the energy landscape for China, but could transform energy policies and development around the world. With China ambitiously pursuing new and renewable energy resources, the stage is set for thorium reactors to emerge as a major resource for China's energy supply.
© Safiyyah Abdul-Khabir. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] K. Bradsher, "China Slows Development of Nuclear Power Plants," New York Times, 24 Oct 12.
[2] M. S. Wickleder, B. Fourest and P. K. Dorhout, "Thorium," in The Chemistry of the Actinide and Transactinide Elements, ed. by L. R. Morss et al. (Springer, 2011), p 52.
[3] S. Zhou and X. Zhang, "Nuclear Energy Development in China: A Study of Opportunities and Challenges," Energy 35, 4282 (2010).
[4] A. Evans-Pritchard, "China Blazes Trail For 'Clean' Nuclear Power From Thorium," The Guardian, 06 Jan 13.
[5] R. Hargraves and R. Moir, "Liquid Fluoride Thorium Reactors," Am. Sci. 98, 304 (2010).
