Liquid fluoride thorium reactor
[2] Molten salt reactors, as a class, include both burners and breeders in fast or thermal spectra, using fluoride or chloride salt-based fuels and a range of fissile or fertile consumables.
The LFTR concept was first investigated at the Oak Ridge National Laboratory Molten-Salt Reactor Experiment in the 1960s, though the MSRE did not use thorium.
[3] Japan, China, the UK and private US, Czech, Canadian[4] and Australian companies have expressed the intent to develop, and commercialize the technology.
[13]: ix Weinberg was removed from his post and the MSR program closed down in the early 1970s,[14] after which research stagnated in the United States.
This was proven to work in the Shippingport Atomic Power Station, whose final fuel load bred slightly more fissile from thorium than it consumed, despite being a fairly standard light water reactor.
Thermal reactors require less of the expensive fissile fuel to start, but are more sensitive to fission products left in the core.
The one-fluid design includes a large reactor vessel filled with fluoride salt containing thorium and uranium.
According to estimates of Japanese scientists, a single fluid LFTR program could be achieved through a relatively modest investment of roughly 300–400 million dollars over 5–10 years to fund research to fill minor technical gaps and build a small reactor prototype comparable to the MSRE.
This bred fissile U-233 can be recovered by injecting additional fluorine to create uranium hexafluoride, a gas which can be captured as it comes out of solution.
The advantages of separating the core and blanket fluid include: One weakness of the two-fluid design is the necessity of periodically replacing the core-blanket barrier due to fast neutron damage.
The effect of neutron radiation on graphite is to slowly shrink and then swell it, causing an increase in porosity and a deterioration in physical properties.
The main design question when deciding between a one and a half or two fluid LFTR is whether a more complicated reprocessing or a more demanding structural barrier will be easier to solve.
A Rankine power conversion system coupled to a LFTR could take advantage of increased steam temperature to improve its thermal efficiency.
[29] The world's first commercial Brayton cycle solar power module (100 kW) was built and demonstrated in Israel's Arava Desert in 2009.
On site processing is planned to work continuously, cleaning a small fraction of the salt every day and sending it back to the reactor.
There is no need to make the fuel salt very clean; the purpose is to keep the concentration of fission products and other impurities (e.g. oxygen) low enough.
[31] Having the chemical separation on site, close to the reactor avoids transport and keeps the total inventory of the fuel cycle low.
One potential advantage of a liquid fuel is that it not only facilitates separating fission-products from the fuel, but also isolating individual fission products from one another, which is lucrative for isotopes that are scarce and in high-demand for various industrial (radiation sources for testing welds via radiography), agricultural (sterilizing produce via irradiation), and medical uses (Molybdenum-99 which decays into Technetium-99m, a valuable radiolabel dye for marking cancerous cells in medical scans).
The lower boiling point fluorides like uranium tetrafluoride and the LiF and BeF carrier salt can be removed by distillation.
Newer designs usually avoid the Pa removal[1] and send less salt to reprocessing, which reduces the required size and costs for the chemical separation.
[104][105] The project is spearheaded by Jiang Mianheng, with a start-up budget of $350 million, and has already recruited 140 PhD scientists, working full-time on thorium molten salt reactor research at the Shanghai Institute of Applied Physics.
[107] At the end of August 2021, the Shanghai Institute of Applied Physics (SINAP) completed the construction of a 2MW (thermal) experimental thorium molten salt reactor in Wuwei, Gansu, known as the TMSR-LF1.
He first researched thorium reactors while working at NASA, while evaluating power plant designs suitable for lunar colonies.
Material about this fuel cycle was surprisingly hard to find, so in 2006 Sorensen started "energyfromthorium.com", a document repository, forum, and blog to promote this technology.
[110][111] An independent technology assessment coordinated with EPRI and Southern Company represents the most detailed information so far publicly available about Flibe Energy's proposed LFTR design.
The Copenhagen Atomics Waste Burner is a single-fluid, heavy water moderated, fluoride-based, thermal spectrum and autonomously controlled molten-salt reactor.
[114] In July of 2024, Copenhagen Atomics announced that their reactor is ready to be tested in a real life scenario with a critical experiment at the Paul Scherrer Institute in Switzerland in 2026.
The Alvin Weinberg Foundation was a British charity founded in 2011, dedicated to raising awareness about the potential of thorium energy and LFTR.
[116][117][118] It is named after American nuclear physicist Alvin M. Weinberg, who pioneered the thorium molten salt reactor research.
The two-reactor unit is designed to be manufactured on an assembly line in a shipyard, and to be delivered via barge to any ocean or major waterway shoreline.
