TMSR (a shortened initialism of English Thorium Molten Salt Reactor Nuclear Energy System translated from Chinese: 钍基熔盐堆核能系统) is a long-term research and development project of the Chinese Academy of Sciences (CAS), begun in 2011 and assigned to its Shanghai Institute of Applied Physics (SINAP), to design, test, and build nuclear reactors that incorporate molten salt as a fuel-carrier and/or coolant, and thorium as a fertile material. The TMSR facilities grew from the collaborative efforts of "nearly 100 domestic research institutions, universities and industrial companies", and are now "the world's only research platform dedicated to molten salt reactors and thorium-uranium fuel cycle studies".
Project 728 In the late 1960s, CAS had begun to contemplate the development of molten salt reactors using thorium. Project 728 was launched in 1970 to develop nuclear power in China to mitigate an energy crisis caused by industrial fossil fuel demand exceeding domestic supply. Its initial goal was to build a 25 MWe power plant based on the 1960s Molten-Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory (ORNL) in the US. A demonstration molten salt reactor (MSR) was built that achieved criticality in 1971, but was not intended to produce power. Further progress was hampered by the technological, industrial, and economic conditions in 1970s China however, and a pragmatic decision was made to develop pressurized light water reactors (PWRs) instead; their first commercial reactor, CNP-300 at Qinshan Nuclear Power Plant, began operations in 1991.
Revisiting 728 The construction of PWRs did not extinguish the interest in MSR technology and Thorium breeding in China however. Due to relatively limited domestic Uranium deposits, China's nuclear power production relies heavily on imported uranium, a strategic vulnerability in the event of e.g. economic sanctions. The use of coal in China since the 1970s had also dramatically increased, and with it came serious air pollution that affected the health of large numbers of citizens. Finding cleaner energy sources became a pressing political concern (Note: modern non-hydro renewable energy in China was not ready until significantly later; PWR nuclear generated over 14 TWh in 1994, while wind power in China did not achieve that until 2009, and solar power in China not until 2014. Generation from hydroelectricity in China had been gradually increasing for decades, but only began rapidly expanding circa 2000.). Some locations also make installing PWRs difficult; the relative lack of water available for cooling them west of the Hu line is seen as a limiting factor for siting them there (cf. Map of Chinese nuclear power plants). The perceived need for non-PWR nuclear in China was thus only increasing. In the 1970s, global Thorium reserves were estimated to be on the order of 1 Mt, and China was not considered to have especially rich deposits. In the 1980s, the rare-earth industry in China began in earnest; rare earths are required for numerous high-tech devices which China manufactures. By the early 1990s, China was producing a majority of the world's rare earths, and by the end of the decade had achieved a near-monopoly. As a byproduct of its mining and refining, it was also generating Thorium far in excess of any non-nuclear needs. By 2009 it was noted that Thorium was being stockpiled in China for future nuclear use. Meanwhile, with the derailed attempt to make a Chinese MSRE clone still in living memory among their senior researchers, a treasure trove of information on how it was actually done unexpectedly appeared: Kirk Sorensen had obtained copies of numerous important historical ORNL research technical documents, and in an effort to raise awareness of Thorium and MSR technology, had them digitized, and then made publicly available on his website beginning in 2006. These new conditions invited a revisit of Project 728's original plan. Following the successful 2009 startup of the Shanghai Synchrotron Radiation Facility, a big science project of national interest to China, Xu Hongjie, who headed its construction, was given a new assignment by CAS: in order to further China's energy policy and sustainable development goals, he should lay the groundwork for an advanced nuclear fission energy program. After a team was assembled, relevant literature reviewed, and topics for research identified, a plan focusing on reactors which use thorium and molten salt was submitted to CAS for approval.
Project launched In January 2011, CAS began the TMSR research and development project to create reactors which, among other advances, would use air cooling. Its initial budget was reportedly ¥3 billion (US$444 million then-equivalent; approximately $635 million as of 2025). and was led by Xu Hongjie through SINAP, which established MSR research facilities in Shanghai's Jiading District. In 2012 a thorium energy conference was held in Shanghai, in partnership with SINAP; speakers included Xu Hongie, and Jiang Mianheng. For the conference, The First Nuclear Era: The Life and Times of a Technological Fixer, the autobiography of Alvin M. Weinberg, who headed ORNL during the MSRE, was translated into Chinese, and copies made available to attendees. By 2014 the smog in China from burning coal had worsened (note e.g. 2013 Northeastern China smog and 2013 Eastern China smog) to a point where TMSR engineers were told to accelerate their efforts to bring a reactor online from 25 years to 10. In 2015, SINAP signed a decade-long Cooperative Research and Development Agreement (CRADA) with ORNL for technology transfer related to the MSRE and associated nuclear innovations. By 2019, the Bayan Obo Mining District was recognized as a major Thorium deposit, with China holding at least 0.1 Mt Recent exploration at Bayan Obo has identified additional, massive Thorium deposits: 220,000 tons proven as of 2025, with total reserves estimated in excess of 1 million tons. The total for all of China is now thought to be 1.4 Mt. By some estimates, this is enough to power China for 60,000 years.
… excerpt ends here. Continue reading the full article.
