Researchers from the Chalmers University of Technology think they’ve developed a method that could eliminate one of remaining obstacles to stable and sustainable nuclear fusion, which could provide the world with a source of virtually limitless clean energy.
Fusion power has the potential to provide clean and safe energy that is free from carbon dioxide emissions. However, imitating the solar energy process is a difficult task to achieve. Two young plasma physicists at Chalmers University of Technology have now taken us one step closer to a functional fusion reactor.
Their model could lead to better methods for decelerating the runaway electrons, which could destroy a future reactor without warning.
To initiate a fusion reaction, three conditions must be satisfied- that including: incredibly high temperatures (to stimulate high-energy collisions); adequate plasma particle density (to ensure a higher likelihood for collisions to occur); and a sufficient amount of time in which the plasma is to be confined (to retain the plasma, which has a tendency to expand, in a defined volume).
Only when all three components are satisfied will the fusion process be initiated.
The largest issue in creating a viable fusion reactor is developing a device able so sustain the immense pressure and temperatures of the plasmas which approach 100 million degrees- 6 times hotter than the core of the Earth.
The Chalmers researchers came up with a method to manage these runaway electrons. They found that injecting heavy ions in gas or pellet form into the reactor slows down the erring electrons by colliding with them. “When we can effectively decelerate runaway electrons, we are one step closer to a functional fusion reactor,” study co-author Linnea Hesslow said in a university press release.
The model takes high pressure and temperatures of about 150 million degrees to get atoms to combine. As if that was not enough, runaway electrons are wreaking havoc in the fusion reactors that are currently being developed. In the promising reactor type tokamak, unwanted electric fields could jeopardise the entire process. Electrons with extremely high energy can suddenly accelerate to speeds so high that they destroy the reactor wall.
It is these runaway electrons that doctoral students Linnea Hesslow and Ola Embréus have successfully identified and decelerated. Together with their advisor, Professor Tünde Fülöp at the Chalmers Department of Physics, they have been able to show that it is possible to effectively decelerate runaway electrons by injecting so-called heavy ions in the form of gas or pellets.
How does it work?
The monstrous apparatus will be the world’s largest tokamak, with a plasma radius (R) of 6.2 m and a plasma volume of 840 m³. In the heart of the reactor remains the massive magnetic coils wrapped around the tokamak, an essential component in confining the temperatures which will approach 150 million degrees C. As all other tokamaks, the massive vessel will charge a gaseous fuel contained by immense magnetic fields. Using extraordinary amounts of electricity will force the gas to break down and become ionized as electrons are stripped from the nuclei. Plasmas will then be formed.
The plasma particles will continue to become energized at they continue to collide at increasing intervals and intensities. Auxillery heating methods will further the plasma temperature’s until fusion temperatures are reached at 150 to 300 million °C. The highly energized particles will be able to overcome the natural electromagnetic repulsion, enabling the particles to collide and fuse, releasing immense amounts of energy.
Despite the great progress made in fusion energy research over the past fifty years, there is still no commercial fusion power plant in existence. Right now, all eyes are on the international research collaboration related to the ITER reactor in southern France.
As efforts to improve the world’s renewable energy sources continue, many see nuclear fusion as having the most potential. It can provide clean energy, with virtually zero carbon emissions, and it isn’t seasonal like solar and wind.
“Considering there are so few options for solving the world’s growing energy needs in a sustainable way, fusion energy is incredibly exciting since it takes its fuel from ordinary seawater,” Hesslow added.
Thankfully, a number of efforts to stabilize nuclear fusion are underway. For instance, a Canadian collective aims to replace fossil fuels with nuclear fusion by the 2030s. That timeline is possible, especially considering the progress made over the past 50 years in fusion energy, but it won’t be easy.
“Many believe it will work, but it’s easier to travel to Mars than it is to achieve fusion. You could say that we are trying to harvest stars here on earth, and that can take time. It takes incredibly high temperatures, hotter than the center of the sun, for us to successfully achieve fusion here on earth. That’s why I hope research is given the resources needed to solve the energy issue in time,” says Linnea Hesslow.
The Maritime Telegraph addressed for the experts’ opinion.
“Hope that in near future it will become ordinary as diesel or gasoline engines which we are using in our cars daily! Just not so long ago we can hear about cold fusion in Sci-Fi movies, but it is knocking in our doors already! Yes, it’s around the corner. The NS Savannah still has a licensed reactor. Let that sink in. The main objective of this project – safety of working process of reaction in the reactor….. and as a result – high quality of experts for service of this type of installations have to be prepared in some special trening centers. Chris Bright Nuclear fusion is likely to remain uncompetitive with nuclear fission because of the much greater energy density of fission. Fission uses solid fuel with a particle density about a thousand times greater than a fusion plasma. The energy of a fission event is typically 200 MeV, over ten times greater than 17.6 MeV for DT fusion. So fission already enjoys an energy density about 10 000 times that of fusion. This translates to a much smaller reactor and lower capital costs. Also, a smaller reactor is much easier to accommodate on board a vessel.
More important, fission already works at the GW scale. Fusion has been achieved at the Joint European Torus (JET) at Culham, UK. This was 16 MWt which lasted for 5 seconds, much smaller than the energy supplied to JET. It is quite likely that fusion will eventually break even and then generate net power. However, that is a question of funding which may not be forthcoming since fission already does the job.” Capt. Nigel Kurtis.
“I think this nuclear reactor cannot now have anything to do with shipping, because it is too uncontrollable at this stage. Perhaps, at least 50 years later, scientists will go into progress with this type of energy reactions. The most optimal in our time is cold fusion, but this solar energy process is totally unstable and uncontrolled.
Not all ships can still use nuclear power at least. When nuclear power works on all ships, then it will be possible to talk about the functional fusion reactor. The modern fleet is very unstable commercially, and nuclear power plants are very expensive. The maintenance of such installations requires very large infusions of money. There even no money for nuclear power, not to speak about a nuclear reactor. Maybe this is possible in the space sphere, but not for shipping.” Chief Engineer Nikolai Borisenko.
“My cousin was the commander of the Komsomolets submarine with a nuclear reactor, and he is not very happy that he worked there, because of the radiation.
Of course, everything is possible in the future, but how safe such thermonuclear reactors are, this is a question.” Chief Engineer Ivan Petrov.
“I think it is very positive to use such energy in all spheres and support such innovations fully. If this really helps to increase the capacity of the vessels, then I am for using this kind of energy.” Capt. Eugene Sapronov.
