The dawn of nuclear fusion has arrived as a fully-fledged part of engineering and a growing market.
According to Affinity Business Insights, the global Nuclear Fusion market will grow continuedly during 2022-2028.
At this time, it’s worthwhile to know what effects nuclear fusion projects will have on the engineering field.
Early in 2022, a group of scientists were able to make a breakthrough in allowing nuclear fusion to be studied in various landscapes.
A series of experiments were conducted in America at the National Ignition Facility.
The laser facility delivers up to 1.9 megajoules of energy in pulses – and has measured peak powers up to 500 terawatts.
To conduct the fusion tests the lasers were used to generate X-rays in radiation cavities to drive a fuel capsule via X-ray ablation pressure.
This resulted in an implosion process that compressed and heated the fuel through mechanical work.
A burning-plasma state was then created that increased the spatial scale of the capsule with different implosion concepts.
Difference between Fission and Fusion
Nuclear fusion energy which is very different from the technology used in nuclear power plants currently needs to be noted.
The principle used in a general nuclear power plant is called nuclear fission. In fission power, we use uranium 235.
During the process as a neutron hits Uranium, the nucleus is separated into two nuclei. When this reaction occurs there exists a difference in total mass from before and after the reaction.
This difference of total mass is released as energy following Albert Einstein’s equation (E=mc2).
The fission reaction also produces a few neutrons and they hit more Uranium.
By way of discreet controlling of reactions, under the operational range, enables continuous production of energy.
Fission requires careful control to prevent the runaway of a reactor to prevent tragedies like Chernobyl and Fukushima.
In contrast, nuclear fusion uses light atoms such as deuterium and tritium (they are the isotopes of hydrogen).
In the reaction between deuterium and tritium (D-T reaction), it produces a helium atom and one neutral atom. There is also a mass difference before and after the reaction, which is equivalent to the energy released.
The concept of a fusion power plant is the utilization of this fusion reaction. The current state of a fusion power plant is in the phase of practical generation of electricity. The theory of fusion is well-developed but there remain a lot of technical issues to solve.
The uniqueness of nuclear fusion energy basically can be described as:
1) The deuterium as fuel exists 1cc within 3L of the usual water. Therefore, there is no resource shortage for nuclear fusion.
2) It produces no waste that contaminates the environment such as CO2 and there is no requirement of material treatment for the ultra-long term.
3) The nuclear fusion reaction at the reactor core can be controlled safely. These three points are often mentioned when making a comparison with nuclear fission. Therefore, let us consider more in detail here.
For point 1, power generation output of 100 million kW with D-T reaction requires 200g of deuterium per day. 150 ppm of hydrogen isotope within the whole amount of water in the ocean is deuterium, therefore we can say deuterium deposits is inexhaustible.
The question is how to separate it from water practically. There is a misunderstanding that the separation of water by electrolysis takes a huge amount of energy and this makes fusion impossible to generate a net of energy at all.
It is true that to divide water by electrolysis and proceed isotope separation consume a great deal of energy, however, water molecular itself has a slight difference in chemical property whether it contains normal hydrogen or deuterium.
Making use of this difference, it is possible to separate deuterium efficiently. Plants for deuterium separation already exist all over the world. Especially, in Canada, it has been well developed and commercialized.
For 2, we should mention that radioactive materials can be produced during the operation of a fusion reactor.
Tritium as fuel is radioactive and it is difficult to produce in terms of cost. Therefore, it can be produced by nuclear reactions between lithium and neutrals from fusion reactions inside the blanket.
The blanket is a device located inside of fusion reactor that contains lithium to produce tritium and inject it as fuel into fusion plasma.
The point is that only a few per cent of the injected fuels (deuterium and tritium) can make a fusion reaction so that the rest would be released as exhaust emission. Tritium has mobility and it must be carefully handled. Another radioactive material can be also produced that energetic neutrals from fusion plasma make plasma-facing components radioactive. This kind of radioactive is a solid-state and low level that it is relatively easy to handle compared with radioactive from fission power reactor. Technology for the blanket has been a key issue and intensively studied.
Finally, 3, we see the reason why there is no runaway with a fusion reactor. In magnetic confinement of fusion plasma, the possible operation range for fusion reaction is very narrow.
These required temperatures and densities of plasma are sensitive for fuel injection or impurities.
If there is an error in operation such as the excess supply of fuel, it cannot sustain the reaction conditions. Then, it terminates automatically. Of course, a sudden termination can cause damage to the reactor so safe operation is also of importance.
In this manner, nuclear fusion energy is not perfectly clean. Even though, the amount of energy that it can produce would be enormous. As one alternative, nuclear fusion should be taken into account.
But what is Nuclear Fusion?
When you think nuclear today you are most likely thinking of nuclear fission where uranium atoms get destroyed. This is the normal procedure of nuclear reactors.
Fusion on the other hand sees hydrogen atoms join to form helium and parts of the matter is converted into energy, light and heat. Essentially it emulates the same reactions as the sun to generate power.
A 2019 conference paper titled Computational Electromagnetics for Nuclear Fusion Engineering and Design explains the fusion process as one where stars are heated through the collision of atomic nuclei which then fuse to form heavier elements that release energy.
According to the paper generation of this kind of energy offers no carbon emissions, is reliable and also considered operationally safe.
One of the most established ways to achieve the conditions required to produce fusion energy is the ability to control a hot gas of fully ionized hydrogen isotopes (plasma) with strong magnets in a ring-shaped magnetic chamber known as a tokamak.
Why is it good?
Hydrogen gas used in fusion is considered one of the world’s inexhaustible fuels and it is also low cost and has the potential to generate more fuel compared to nuclear fission used in reactors currently.
Most importantly the fusion doesn’t create waste (radioactive) and reactors supplied with the fusion simply stop working once its fuel source runs dry.
Fission reactors on the other hand continue to generate waste and heat even when it’s stopped.
Nuclear Fusion is far-reaching but one of its major contributions toward new technology is its sustainability, and hydrogen technologies is a good example of how nuclear fusion drives change in several sectors, like automotive and energy.
What should engineers know about Nuclear Fusion?
There are many areas where a trend shift toward Nuclear Fusion is expected and Computational Electromagnetics for Nuclear Fusion Engineering and Design gives insight into several elements that need to be overcome to allow the Nuclear Fusion market to grow.
Electric Arcs
Under certain conditions, the electric fields induced around a tokamak reaction generates powerful electric arcs that can damage machines.
Engineers have to look at ways to lessen these arcs and one way is to identify Paschen’s law and use it as a way to figure out the equation to know the necessary voltage necessary to start an arc with the pressure of the gas and the distance between the electrodes.
When this is established it’s possible to calculate the damage and then work on ways within structures to ensure the damage is maintained.
Application of Colorimity
New research into colorimetry offers a unique take on nuclear fusion research where the distribution and deposition layer on the surface of vacuum vessels is looked at. Since the deposition layer affects fuel particles.
The paper Colorimetry in Nuclear Fusion Research found that during an arc discharge up to 60% of the fuel particles were absorbed by the wall of vessels or where the fusion takes place.
It was found that the color analysis method using a color analyzer could evaluate the deposition layer that is formed on the plasma-facing wall by color analysis.
How to ‘steel’ the show
Materials to use infusion technology is more important than ever and as a result steel has come under the microscope.
The paper Technological Processes for Steel Applications in Nuclear Fusion show that there’s a great advancement in having materials that won’t be affected negatively during the general effects of nuclear fusion.
The properties of the EUROFER97 steel is now being considered as tops as it allows for optimal temperatures and doesn’t show critical defects or recognizable damage during the fusion process.
So, what now?
According to the World Nuclear Association except for sustainable energy production, the application of nuclear technology is pinpointed at times with transport like ships and cars seeing a lot of favor to adapt perfected nuclear fusion technology.
Peaceful Nuclear Explosions
Civil engineering could benefit greatly from these explosions if it is done in an ideal way where radioactive waste is not generated.
These kinds of explosions have the potential to create dams, waterways and a myriad of other elements that could see effective city planning in the future.
Centralized Heating
Many reactors in cold climates provide hot water for district heating, without significant penalty in electrical performance. This usually replaces fossil fuel sources, with a significant reduction in carbon dioxide emissions.
Most of the nuclear district heating has been developed within northern European or former Soviet states as the cold climate and long heating periods create favorable conditions for district heating and cogeneration development.
Apart from new reactors designed specifically for district heat, this service may be from a power reactor’s condenser circuit or from tapping into the secondary steam circuit.
This is being demonstrated at the Haiyang nuclear power plant in China, to heat the whole city with 300-400 TJ/yr. It is planned for the new CAP1400 plant in Shandong, and plants at Qinshan, Tianwan and Hongyanhe. If simply tapping the condenser circuit is more widely done, water at around 100 °C at low pressure is required.
China has three low-temperature reactor designs specifically for district heating rather than power. GCN has the NHR-200 (200 MWt) at Daqing city, CNNC has the DHR-400 Yanlong (400 MWt), and SPIC has the 200 MWt LandStar-I which delivers hot water at 110°C with convection circulation through a heat exchanger.
Water Desalination
Portable water is in short supply in many parts of the world. Lack of it is set to become a constraint on development in some areas.
Nuclear energy is already being used for desalination and has the potential for much greater use.
Nuclear desalination is generally very cost-competitive with using fossil fuels.
As well as desalination of brackish or seawater, treatment of urban wastewater is increasingly undertaken.
It is estimated that one-fifth of the world’s population does not have access to safe drinking water and that this proportion will increase due to population growth relative to water resources.
Conservation
The Rhisotope Project is investigating the use of radioisotopes in the prevention of rhino poaching.
The University of Witwatersrand in collaboration with the Australian Nuclear Science and Technology Organisation (Ansto), Colorado State University, Rosatom and the Nuclear Energy Corporation of South Africa (Necsa), is examining the possibility of injecting trace amounts of stable isotopes into the horns of rhinos, to disincentivize poaching and to increase the chances of identifying and arresting smugglers.
Hydrogen Economy
The April 2021 report, Making the Hydrogen Economy Possible, by London, UK-based think-tank Energy Transitions Commission sets out the role of clean hydrogen in achieving a highly electrified net-zero economy.
It outlines the increase of clean hydrogen to 50 million tonnes by 2030 and projects 500 to 800 million tonnes of annual clean hydrogen consumption by 2050. About 85% of this is likely to be green hydrogen. Hydrogen and fuels derived from it would then account for some 17% of total final energy demand (on top of 68% being electricity).
The main increase in demand would be from those sectors which are hard or expensive to directly electrify, such as steel production and shipping. All this hydrogen needs to be zero-carbon via electrolysis using up to 30,000 TWh/yr (on top of 90,000 TWh/yr for direct electrification).
The International Energy Agency’s (IEA’s) Energy Technology Perspectives 2020 in its Sustainable Development Scenario projects global hydrogen production growing rapidly to about 445 Mt for energy use plus 75 Mt for process use by 2070.
The 520 Mt hydrogen would be produced 58% by electrolysis and 40% from fossil fuels with carbon capture and storage (CCS). Of the energy demand, 60% is for transport, and of the process used, 60% is chemical and 40% steel production.
References:
Otin, Ruben & Aria, Shafa & Thompson, Vaughan & Lobel, Rob & Willians, John & Vizvary, Zsolt & Iglesias, Daniel & Porton, Michael & Contributors, JET. (2019). Computational electromagnetics for nuclear fusion engineering and design.
Motojima, Gen. (2022). Colourimetry in Nuclear Fusion Research. 10.5772/intechopen.101634.
Rieth, Michael & Duerrschnabel, Michael & Bonk, Simon & Jäntsch, U. & Bergfeldt, Thomas & Hoffmann, Jan & Antusch, Steffen & Simondon, Esther & Klimenkov, Michael & Bonnekoh, Carsten & Ghidersa, Bradut-Eugen & Neuberger, H. & Rey, Jörg & Zeile, Christian & Pintsuk, Gerald & Aiello, Giacomo. (2021). Technological Processes for Steel Applications in Nuclear Fusion. Applied Sciences. 11. 11653. 10.3390/app112411653.
