We need badly to develop and build Thorium based molten salt fast breeder nuclear reactors to secure our energy needs in the future. Lest anyone should be threatened by the words fast breeder, it simply means it uses fast neutrons instead of thermal neutrons, and breeder means it produces more fissible material than it consumes, in the case of Thorium the ratio is about 1.05.
LFTR is a type of Molten Salt Reactor with equipment to convert plentiful thorium into uranium (U233) to use as fuel. It can also use plutonium from LWR waste. LFTR is not very efficient at using depleted uranium (need a Fast-Spectrum reactor to fission U-238 effectively; in a thermal-spectrum reactor like LFTR or LWR, would convert some U-238 to plutonium which is fissile).
Because a LFTR fissions 99%+ of the fuel (whether thorium, or plutonium from nuclear waste), it consumes all the uranium and transuranics leaving no long-term radioactive waste. 83% of the waste products are safely stabilized within 10 years. The remaining 17% need to be stored less than 350 years to become completely benign.
“LFTR technology can also be used to reprocess and consume the remaining fissile material in spent nuclear fuel stockpiles around the world and to extract and resell many of the other valuable fission byproducts that are currently deemed hazardous waste in their current spent fuel rod form. The U.S. nuclear industry has already allocated $25 billion for storage or reprocessing of spent nuclear fuel and the world currently has over 340,000 tonnes of spent LWR fuel with enough usable fissile material to start one 100 MWe LFTR per day for 93 years. (A 100 MW LFTR requires 100 kg of fissile material (U-233, U-235, or Pu-239) to start the chain reaction). LFTR can also be used to consume existing U-233 stockpiles at ORNL ($500 million allocated for stockpile destruction) and plutonium from weapons stockpiles.”
FS-MSRs essentially avoid the entire fuel qualification issue in that they are tolerant of any fissile material composition, with their inherent strong negative thermal reactivity feedback providing the control necessary to accommodate a shifting fuel feed stream. Fast Spectrum Molten Salt Reactor Options,
Some of the pictures are from a slide presentation given by David Archibald in Melbourne Feb 5 2011. He posted it “for the benefit of all” which I have interpreted as waving the copyright of the pictures
With a Molten Salt Reactor, accidents like the Three Mile Island disaster will not happen. Ah yes, I remember it well, March 28, 1979. We lived in South East Pennsylvania at the time, well outside the evacuation zone, but a fellow engineer at work took off, took vacation and stayed at a hotel in western Virginia over the weekend fearing a nuclear explosion. My wife went to a retreat just outside the evacuation zone, and none of them so much as heard of any problem, there never was any evacuation. There was concern though, and a disaster it was indeed with a partial meltdown of the core, rendering the installation a total loss, just a big, forever cleanup bill. The cost so far has totaled over 2 billion dollars.
A combination of personnel error, design deficiencies, and component failures caused the TMI accident, which permanently changed both the nuclear industry and the NRC. Public fear and distrust increased, NRC’s regulations and oversight became broader and more robust, and management of the plants was scrutinized more carefully. Careful analysis of the accident’s events identified problems and led to permanent and sweeping changes in how NRC regulates its licensees – which, in turn, has reduced the risk to public health and safety.
The side effect of increased regulation is increased cost and delay in construction of new nuclear plants. Eventually, more than 120 reactor orders were cancelled, and the construction of new reactors ground to a halt. Of the 253 nuclear power reactors originally ordered in the United States from 1953 to 2008, 48 percent were canceled.
Another side effect of the TMI accident is fear of trying a different and safer approaches, since they conflict with existing regulations. The next Nuclear power reactor came online in 2016, but it is the same type of boiling water reactor as before, not a Molten Salt Thorium reactor with its increased safety.
United States used to be the leader in Thorium usage. What happened?
The 40 MWe Peach Bottom HTR in the USA was a demonstration thorium-fueled reactor that ran from 1967-74. and produced a total of 33 billion kWh.
The 330 MWe Fort St Vrain HTR in Colorado, USA, ran from 1976-89. Almost 25 tons of thorium was used in fuel for the reactor.
However, after 10 years passed and billions invested, the U.S. Atomic Energy Commission abandoned thorium research, with uranium-fueled nuclear power becoming the standard. In the 1980s, commercial thorium ventures failed, such as the Indian Point Unit I water reactor near New York City, because of the vast financial costs and fuel and equipment failures. By the 1990s, the US nuclear power industry had abandoned thorium, partly because thorium’s breeding ratio was thought insufficient to produce enough fuel for commercial industries.
Some research and development is still conducted, but it is more concentrated in protecting the U.S. leading position in monitoring and controlling existing nuclear technology. Even the Netherlands is developing a molten salt thorium reactor.
Virtually no spent fuel problem, very little on site storage or transport. I am following the events at Fukushima Nuclear Power plants with great interest. How ironic that the greatest risk is with the spent fuel, not with the inability to shut down the working units. The spent fuel issue is the real Achilles’ heel of the Nuclear Power Industry. Molten Salt Thorium nuclear power works differently from conventional Uranium as the fissile fuel gets generated in the breeding process itself and nearly all fuel gets consumed as it is generated. When the process shuts down, that is it. Only the radioactivity that is en route so to say will have to be accounted for, not everything generated thus far in the process. The difference is about one to ten thousand in the size of the problem. It is high time to rebuild and expand our Nuclear power generation by switching to Thorium.
Molten Salt Nuclear Reactors have a very high negative temperature coefficient leading to a safe and stable control. This is another beauty of the molten salt design. The temperature coefficient is highly negative, leading to a safe design with simple and consistent feedback. What does that mean? It means that if temperature in the core rises, the efficiency of the reaction goes down, leading to less heat generated. There is no risk for a thermal runaway. In contrast, graphite moderated generator can have a positive temperature coefficient which leads to complicated control, necessitating many safety circuits to ensure proper operation and shutdown. Their failure mode is they go prompt critical, and no containment vessel can contain the explosion that would occur, so they are built without one.
With Molten Salt nuclear Reactors there is no risk for a meltdown, the fuel is already molten, and that is a safe design. The fissile fuel in a Thorium reactor is U-233 in the form of UraniumFluoride (UF4) salt which also contains Lithium and Beryllium. In its molten form it has a very low vapor pressure. The salt flows easily through the heat exchangers and the separators. The salt is very toxic, but it is completely sealed. Being a fluid, it is constantly mixed for optimum efficiency. The reactor will never have to be shut down for refueling, it is a continuous flow process. Uranium-235 Nuclear reactors on the other hand have to be shut down for refueling and rebalancing of the fuel rods a little more often than once every two years. The average shutdown is 35 days, or about 5% of the time. Then comes the major problem of safely and securely transporting and reprocessing the spent fuel.