FAQ

Vision, philosophy, technology...
Questions and brief answers 

What is a TMX-START?


TMX-START stands for Transmutex Subcritical Transmutation Accelerated Reactor with Thorium. It is the combination of a nuclear reactor that cannot go "critical" like a bomb, termed "subcritical", with a particle accelerator required to "push" the radioactive reaction. In short, in a regular nuclear reactor you have to "down-modulate" the chain reaction to remain under control, whereas in a TMX-START you have to "up-modulate" the nuclear reaction using a particle accelerator to extract energy out of it. If the particle accelerator stops, the reaction stops immediately (2ms) making the system extremely safe.




Critical vs. subcritical reactor?


A critical nuclear reactor uses spontaneous fissions producing neutrons which multiply until their number is stabilized at a proposed level by a control system.

A sub-critical reactor needs an external source of neutrons in order to reach the proposed level of future fissions which number is controlled by the external source. In brief, in a critical reactor you have to "down-modulate" the nuclear reaction to keep it under control, whereas in a subcritical reactor you have to "up-modulate" the reaction to extract energy, making it extremely safe.




Why do you need a particle accelerator?


A TMX-START relies on a subcritical reactor, no fission could happen until external neutrons are supplied by an outside source. In our case, the neutron source is a proton accelerator, heavy positively charged particles accelerated at near the speed of light. When the protons hit a metal target that is placed inside the reactor they "convert" into neutrons through a process called spallation. These neutrons in turn initiate the transmutation process in the fuel that in turns creates massive amount of energy.




Why a cyclotron rather than a linear accelerator?


Various systems can produce high energy protons, including Linear accelerators (LINAC) and cyclotrons.

Transmutex selected a cyclotron because of its smaller footprint that is more adapted to industrial usage.




What is the Fuel cycle?


Thorium is mixed with long-lived nuclear waste, such as Plutonium (Pu), to make the fuel for the TMX-START.

The Pu and other long-lived waste, such as minor actinides, will be mixed with thorium to be consumed in the fast neutrons flux, but also will iniate the transmutation process of Thorium into energy dense Uranium233.




What is cross section?


In nuclear physics the cross section is the probability of interaction of a particle in a given reaction. The cross section is similar to a surface which unit is the BARN. A barn is equivalent to 10−28 m2.




Why breeder reactor?


A breeder reactor extracts most of the energy contained in uranium or thorium, decreasing fuel requirements by a factor of 30 compared to widely used once-through light water reactors, which extract less than 1% of the energy in the uranium mined from the earth.




Why lead-bismuth coolant?


Liquid Metal coolants allows the system to work under atmospheric pressure with high efficiency for increased safety. In addition, neutrons can navigate in lead-bismuth, losing only a small fraction of their energy by elastic scattering. Several thousand elastic scattering are need to absorb them. This adiabatic decrease fosters efficient burning of the long-lived waste. During its travel into the lead-bismuth medium, a neutron increases dramatically its probability to enter into collition ("interaction") with nucleus of long-lived radioactive waste and to transform them into two smaller short-lived fission products. It reduces the radioactivity of nuclear waste from 300,000 years for large nucleus to 300 years for the two smaller nucleus, a factor of x1000!




Thorium vs Uranium?


Thorium offers a sustainable fuel cycle, waste treatment and waste reduction. Given the large potential worldwide expansion in nuclear generation it is likely that, in the medium term, the demand for uranium will increase. Although at present the effect of this on uranium price is only marginal; in the future this is likely to change with demand-led price rises predicted. Hence the option to utilize alternative fuels such as thorium will become more attractive. Thorium reserves are currently estimated to be three to five times more abundant than uranium, with the advantage of being used at 100% instead of .7% for the Uranium in conventional reactors.

A side benefit of using thorium fuel is non-proliferation as uranium enrichment technology is not required. Additionally, using thorium in a breeding cycle as a nuclear fuel also generates isotopes which are high energy gamma emitters, therefore making handling and subsequent diversion of materials to bomb-making much more difficult.




What is Energy?


Energy is the ability to do work: plants to grow, animals to think or move, machines displace or fashion anything. Energy is the fundamental underpinning of Life.

Nuclear Energy is created from the change in mass of matter following the famous equation determined by Albert Einstein: E = mC2, where m is the mass and C2 is the square of the speed of light. If you break a large atom nucleus into two smaller ones there will be a very slight mass differential, but since C2 is such a large number, a massive amount of energy is released. That is the magic of nuclear energy, a million times more powerful than any other energy source on earth.




Is TMX-START a Generation IV reactor?


TMS-START is not officially a Generation IV reactor since it was not included in the list of reactors. The main difference with current Gen IV reactor is the "subcritical" nature of the reactor. All other Gen IV reactor have to rely on "critical" nuclear reaction to function, not the Transmutex START, making it extremely safe. For reference, the official Gen IV reactor technologies include: Gas-cooled Fast Reactor (GFR), Lead-cooled Fast Reactor (LFR), Molten Salt Reactor (MSR), Supercritical Water-cooled Reactor (SCWR), Sodium-cooled Fast Reactor (SFR) and Very High Temperature Reactor (VHTR). TMX-START is an entirely new nuclear energy process, yet it has been experimentaly demonstrated at CERN and the Paul Scherrer Institute in Switzerland, placing it ahead in readiness ahead of many GEN IV technology concepts.




What is spallation?


Spallation is the process by which an accelerated particle (an electron or best a proton) hits a heavy nucleus provoking the ejection of several of its neutrons.




What are the differences between TMX-START and a Fast Neutron Reactor?


An TMX-START is a subcrital reactor intrinsically safe as needing an external source of neutrons to "up-modulate" the reactivity, a Fast Neutron Reactor is traditionally a critical reactor needing to be "down-modulated" and closely monitored to avoid becoming subcritical and uncontrolable.




Is Fusion the future of Energy?


TMX believes Fission, Fusion and Transmutation will all be necessary to provide our civilization with sustainable carbon-free energy. But only Fission and Transmutation are advanced enough to become operational within the decade, in time to mitigate the worst effects of climate change. Fusion will probably only happen on a commercial scale within the late second half of the XXI century, too late for fighting a disastrous climate shift.

Research is working to reach long duration plasma, and fusion will still require decades before operational reactors are finalized, and several other decades before a sufficient number of reactors are operational to provide the world with the massive quantity of energy required.

TMX-START relies on available technologies, able to provide immediate massive amounts of energy, and helping reduce current nuclear wastes.




What TMX-START can bring to PWR?


We have calculated that one TMX-START will eliminate the long-lived nuclear wastes of three conventional reactors each of equivalent power and treat them in situ eliminating the workload of transportation.




What nuclear waste can be transmuted by TMX-START?


The fast neutron flux of a TMX-START will "burn" most long-lived waste, including Plutonium, Neptunium and Americium. As a result, we expect a x100 reduction in long-lived waste volume from the raw spent nuclear fuel that is stored at US nuclear plants.




What is the Levelized Cost of Energy from a TMX-START?


Transmutex aims to reach a Levelized Cost Of Energy (LCOE) at less than $70/MWh. A recent review of exiting data in the field demonstrated that when comparing, with the same hypothesis, GW-scale nuclear power plants and TMX-START, the LCOE is confirmed to be of the same order of magnitude even with appropriate uncertainties at this stage of the project. This result took into account a series of assumptions among which some specific equipment procurement costs (cyclotron, SVBR...), and Operation and Maintenance cost which are particularly uncertain for any GEN IV project, as little to no experience feedback is available.

Furthermore, transmutation of existing long-life radioactive waste would be an additional revenue source as it reduces the burden of waste management and generates electricity.





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