If Alvin Weinberg, probably the most famend director of Oak Ridge Nationwide Laboratory, have been alive right now, he would seemingly agree with Kirk Sorensen, the founding father of Flibe Vitality Inc., {that a} molten salt reactor such because the one developed by ORNL groups within the Fifties and Nineteen Sixties would result in a extra sustainable electrical energy supply than the pressurized water reactor (PWR) that Weinberg co-invented within the Nineteen Forties.
PWRs, first used to propel submarines, are on the coronary heart of two-thirds of the world’s nuclear energy crops right now.
Weinberg lengthy promoted the ORNL-designed molten salt reactor experiment (MSRE) primarily based on Glenn Seaborg’s 1942 discovery utilizing a cyclotron that bombarding thorium with neutrons that finally yields uranium-233, a possible gas for a nuclear reactor. As a result of U-233 undergoes fission, producing warmth and neutrons, it may be harnessed to make electrical energy and convert thorium within the blanket area of a reactor to protactinium, which might be drawn right into a tank the place it decays in a few month into U-233. This product can refuel the reactor from which its precursor got here.
In a chat to Mates of ORNL, Sorensen famous that thorium, which might be discovered all around the world in soil and rocks, is a extra sustainable supply of nuclear gas than the uranium which has been largely mined from the Colorado Plateau, on tribal lands the place Native Individuals are nonetheless recovering from the dangerous well being and environmental impacts of “uranium mining operations within the first period of nuclear growth.”
He added that “if decreased to steel, in a median cubic meter of filth, wherever on the earth, there are about two sugar dice volumes of thorium and one-half a sugar-cube quantity of uranium. And there’s extra vitality on this small quantity of thorium than in an equal cubic meter of the best anthracite coal or crude oil.”
Sorensen in contrast the big PWRs of the Seventies to the landline phone, the small modular reactors (SMRs) primarily based on light-water reactors to the flip cellphone, and the brand new designs of liquid salt reactors primarily based on the ORNL idea to the smartphone. He defined that PWRs and SMRs primarily will produce electrical energy, simply because the landline and flip telephones mainly perform as telephones.
Just like the smartphone, which does a lot greater than make telephone calls, Sorensen stated that the lithium-fluoride thorium reactor (LFTR) his personal Alabama firm has designed and is proposing to construct shall be greater than an influence supply. It’s going to present a relentless movement of medical isotopes. It may well destroy high-level nuclear wastes. It may well generate giant quantities of warmth for teasing hydrogen from water.
Scorching molten salts from the LFTR might present warmth at a temperature of 650 levels Celsius to drive supercritical carbon dioxide by a small turbine to make electrical energy at an effectivity of 45%.
A number of the created U-233 (like that saved at ORNL, which he known as “the goose laying golden eggs”) might be allowed to decay into actinium-225, which is transported to medical facilities the place it decays to bismuth-213, an emitter of alpha particles; utilizing an ORNL invention, such focused alpha remedy is presently used for treating mind and different tumors, bladder most cancers and leukemia.
The corporate’s aim, he stated, is to construct LFTR energy crops between 2030 and 2035 to provide municipalities with 20-30 megawatts of electrical energy.
Since 2006, Sorensen has been a public proponent of thorium reactor know-how, giving quite a few talks throughout Europe and North America, in addition to in Asia and Australia. After founding Flibe Vitality in Huntsville, Alabama in 2011, he led the corporate’s efforts in creating the LFTR and finishing up an industry-funded conceptual research for the Electrical Energy Analysis Institute. He has spoken at molten-salt-reactor workshops at ORNL.
In his discuss, Sorensen argued that the LFTR and different liquid salt reactors, moderately than the normal and modular light-water reactors (together with PWRs), are the important thing to an reasonably priced, sustainable vitality future. He gave these comparisons.
PWRs use water below strain to chill the strong uranium gas and carry its vitality to warmth exchangers to warmth a working fluid to make steam to drive a turbine to provide energy. The LFTR will use a liquid salt consisting of fluorine, lithium and beryllium (that’s why Sorensen’s firm known as FLiBe – these components’ symbols). The salt, which consists of lithium fluoride and beryllium fluoride (LiF and BeF2), has two functions.
First, the salt will function a coolant that carries the reactor’s warmth to the working fluid. Second, the salt will include the nuclear gas, which is uranium-233 within the type of uranium tetrafluoride. The reactor may also have a blanket of liquid salt that incorporates thorium tetrafluoride. It’s going to soak up lots of the reactor’s neutrons (slowed down by a graphite moderator) and finally the contents will decay exterior the reactor core into U-233 nuclear gas.
As a result of the LFTR gas is already in liquid kind, the notion of a reactor meltdown is meaningless on this design as a security threat. In keeping with the flibe.com web site, “Any improve in working temperature reduces the density of the liquid salt which in flip, causes the response to sluggish and the temperature to fall. The LFTR can be designed with a easy frozen salt plug within the backside of the reactor core vessel. Within the occasion of energy loss to the reactor, the frozen salt plug rapidly melts, and the gas salt drains down right into a storage tank under – inflicting a termination within the fission course of.”
The LFTR, Sorensen famous, operates at a excessive temperature however ambient strain; because of this, not like the PWR, which runs at excessive strain, a big, thick, reactor strain vessel and different high-pressure infrastructure usually are not required. Consequently, the LFTR might be constructed on meeting traces resembling these utilized in shipbuilding, decreasing its general value.
As a result of uranium enrichment is required to supply gas for light-water reactors, Sorensen stated, there’s a threat that enriched nuclear gas might be diverted from the method for weapons functions.
“Nobody has ever made an operational nuclear weapon from uranium-233,” he added.
The issues concerned with nuclear waste administration are cited as a significant objection to increasing nuclear energy to interchange fossil gas sources of electrical energy and thus scale back carbon dioxide emissions. Nuclear wastes from PWRs embody extremely radioactive, long-lived transuranic wastes that require everlasting geologic disposal, however wouldn’t be produced in LFTRs, Sorensen stated.
In keeping with the flibe.com web site, “LFTRs will produce far much less waste than present reactors alongside the whole gas cycle and course of chain, from ore extraction to nuclear waste storage. Lithium reactor know-how will also be used to eat the remaining fissile materials obtainable in spent nuclear gas stockpiles around the globe and to extract and resell lots of the worthwhile fission merchandise which might be presently thought of waste.”
In his FORNL discuss, Sorensen implied that he and Weinberg would agree on one other level: the U.S. authorities has supplied a mixture of help for and resistance to efforts to excellent an invention that guarantees to satisfy world vitality wants with a clear, dependable, passively secure and scalable supply of electrical energy, in addition to providing different advantages.
