More on Fusion
What is nuclear fusion?
Nuclear fusion is a reaction between two or more atomic nuclei to form new, different nuclei while absorbing or releasing significant amount of energy. Most nuclear fusion reactions featuring reactant nuclei lighter than iron (56Fe) are accompanied by significant energy release due to a net difference in the reactant and product masses. The mass difference is attributed to the different nuclear binding energies between the reactant and product. The reaction occurs once the nuclei are close enough for the strong force to overcome the Coulomb repulsive force, which increases as the gap between the nuclei closes. To reach the small distance of 10000-th of a Hydrogen atoms size, very high impact energies are required.
The preferred reactants for energy production purposes using nuclear fusion are of the Hydrogen variety or of small atomic masses, as these nuclei would encounter smaller Coulomb repulsion as well as featuring the release of large amounts of energy.
As the two positively charged atomic nuclei collide, there is roughly a 0.01% chance of fusion reaction to occur, while a 99.99% chance for the colliding nuclei to scatter. To overcome this discrepancy the reactants are confined to a thermal medium featuring fuel particles with very high impact energy. Such a medium is referred to as a very hot, fully ionized plasma. Under terrestrial condition such a fusion plasma has temperatures north in range of 150 million ⁰C.
Why Fusion?
Fusion compared to other power
Why Fusion?
Fusion compared to other power
Electricity consumption per capital in the household sector in the EU in 2021 was 1.671 kWh per capita. This can be achieved by:
❑ 700 kg Coal, with a plant operating at 30 %, assuming 1kg coal releases ~ 8kWh
❑ 460 kg Oil, with a plant operating at 30 %, assuming 1 kg oil releases ~ 12 kWh
❑ 123 g reactor grade enriched uranium with a plant operating at 30 %, assuming 1 kg of it releases ~ 45000 kWh
❑ 18 kg H2O and 4g Li to extract the fuel for fusion, assuming the plant operates with 1 % efficiency.
Fusion energy production can provide a low risk, high energy density and environmentally friendly option for nuclear base-load energy production.
FUSION
FISSION
Fuel cycle & Waste disposal
Fuel is generated from H2O and Li → high abundance.
Reaction products are not radioactive – no need for long-term waste disposal strategies.
Use of U → less abundant fuel and requires long- term waste disposal strategies.
Ignition & Safety
There are no spontaneous fusion reactions occurring – no runaway reactions.
Dominated by spontaneous nuclear reactions – mode of operation relies on chain reactions.
Readiness & Costs
Applications are not demonstrated – high risk investment.
An established and demonstrated technology.
FUSION
- Fuel cycle & Waste disposal
- Fuel is generated from H2O and Li → high abundance.
- Reaction products are not radioactive - no need for long-term waste disposal strategies.
- Ignition & Safety
- There are no spontaneous fusion reactions occurring - no runaway reactions.
- Readiness & Costs
- Applications are not demonstrated - high risk investment.
FISSION
- Fuel cycle & Waste disposal
- Use of U → less abundant fuel and requires long- term waste disposal strategies.
- Ignition & Safety
- Dominated by spontaneous nuclear reactions - mode of operation relies on chain reactions.
- Readiness & Costs
- An established and demonstrated technology.
Approaches and challenges to nuclear fusion
Any fusion reactor concept needs to contain and confine the fuel, which is a hot plasma. There are several competing reactor concepts available in different stages of maturity.
- The most widespread approach, magnetically confines the fuel and requires long-duration burns with good insulation and lower fuel density.
- Another successful approach inertially confines the fuel, resulting in short, intensive, explosive bursts and high fuel densities.
There are multiple different approaches in between these two concepts. All approaches feature common and unique challenges arising from their concept.
Fusion Strategies
There are several different competing reactor concepts aimed at nuclear fusion realisation, the choice of which strongly determines the development and/or procurement of required relevant technologies and reactor concepts
Fusion Reactors
The leading fusion reactor contenders broadly fall in Magnetic Confinement Fusion (MCF) categories: linear and mirror devices, large aspect ratio tokamaks, spherical tokamaks and stellarators; Inertial Confinement Fusion (ICF) and Alternative Confinement Fusion.
Concept Decisions
The choice of a fusion reactor concept falls under the purview of mid to long-term goals within the scope of the industry, as it locks in various subsystems and technologies required to achieve the planned reactor.
There are several
different competing reactor concepts aimed at nuclear fusion realisation, the choice of which strongly determines the development and/or procurement of required relevant technologies and reactor concepts
The leading fusion reactor
contenders broadly fall in Magnetic Confinement Fusion (MCF) categories: linear and mirror devices, large aspect ratio tokamaks, spherical tokamaks and stellarators; Inertial Confinement Fusion (ICF) and Alternative Confinement Fusion.
The choice of a fusion reactor
concept falls under the purview of mid to long-term goals within the scope of the industry, as it locks in various subsystems and technologies required to achieve the planned reactor.
Fusion Reactor Selection
Arriving at the optimal choice for a fusion reactor requires addressing a set of global considerations applicable to all reactor concepts and specific considerations applicable to a selected confinement type:
- Considerations common to all reactor types:
- Fuel mix and cycle
Fuel Composition Options
A wide range of different fuel compositions are currently being explored, such as D - T, D - D, He3 - D, p - B and others, each presenting with different ignition conditions, extensive shielding requirements, fuel cycle and breeding considerations, fundamentally influencing reactor design.
- Nuclear shielding
Radiation Intensity Factors
The nature of fusion fuel ignition and burn makes generating fast neutrons unavoidable. Therefore shielding against neutron radiation is inevitable and necessary. The fuel composition and mixture most often determine how intensive and energetic the expected radiation may be.
- Heat shielding
- Nuclear waste disposal
Neutron Activation Challenges
Despite the fusion fuel cycle having next to no radioactive waste products, the expected high-intensity neutron radiation emitted by various fusion reactions causes neutron activation of structural elements. Such elements tend to have a medium to short half-life requiring serious consideration for maintenance and decommissioning protocols.
- Power generation
Scaling for Industry
Regardless of the confinement and reactor archetype chosen for fusion energy production, the energy released from the ignited plasma typically follow one or all of the following channels: high-energy neutrons, high-energy charged particles and a broad spectrum of EM radiation. To successfully put nuclear fusion on the grid, existing and novel technologies must be employed to efficiently use the exit channels for fusion energy while remaining mindful of machine protection measures.
- Industrial scaling
Efficient Maintenance
Beyond developing a successful reactor concept, another crucial aspect is the ability to scale technologies to meet the required industrial demand for energy production.
- Maintenance strategies
- Nuclear licensing:
- Considerations which are specific to a chosen reactor type
- Confinement and ignition
- Mode of operation
Technologies and infrastructure critical to nuclear fusion
Any fusion power plant requires the development of unique technologies and methods specific to its design, such as:
- fuel cycle-related development and management techniques
- fuel-confinement and subsequent ignition-related techniques,
- development of novel heat-load-resistant materials
- development of neutron radiation-resistant materials
Each reactor concept features unique R&D challenges, specific to its design philosophy, such as magnet, vacuum, cryogenic or laser technologies
Technologies and infrastructure critical to nuclear fusion
outstanding issues
Infrastructure Focus
The development of critical technologies and infrastructure falls under the purview of the short to mid-term goals with the fusion industry's scope aiming to solve incremental and outstanding issues in the path of fusion energy production.
Innovative Solutions
Any fusion power plant requires the development of unique technologies and methods specific to fulfil various functions necessary to operate the plant in question. While the primary objective of these technologies is the service of fusion reactors, they may field various alternative applications and can/should be marketed as such.
Critical fusion technologies to be developed and exploited
- High-Temperature Superconductivity (HTS)
- Ultra-High Vacuum Technologies
- Fuel Production:
- Tritium generation
- Helium 3 production
- Material Science:
- Heat-resistant material development
- Neutron-resistant material development
- Power storage technologies
- Others: TBD
Who are the players
- National research laboratories focus on fundamental research into various aspects of fusion plasmas, such as plasma physics, reactor design, material sciences, neutron physics and many other relevant topics.
- Nationally or Internationally funded fusion projects consist of several state/government-backed initiatives to develop and demonstrate a fusion-relevant reactor and prototype.
- Parallel to the previous is a strong uptake in many start-up companies, forming the Private Fusion Sector, aiming to develop and field fusion reactor concepts to demonstrate net power production.
- Both approaches are supported by start-ups or well-established industrial players forming the fusion supply chain, which focuses on components and supporting manufacturing.
- The final participants in this landscape are governmental entities focused on developing a regulatory framework.
National research laboratories
Focus on fundamental research into various aspects of fusion plasmas, such as plasma physics, reactor design, material sciences, neutron physics and many other relevant topics.
State/government-backed initiatives
Nationally or Internationally funded fusion projects consist of several state/government-backed initiatives to develop and demonstrate a fusion-relevant reactor and prototype.
Private Fusion Sector
Parallel to the previous is a strong uptake in many start-up companies, forming the Private Fusion Sector, aiming to develop and field fusion reactor concepts to demonstrate net power production.
Start-ups & industries
Start-ups & industrial players both approaches are supported by start-ups or well-established industrial players forming the fusion supply chain, which focuses on components and supporting manufacturing.
Governmental entities
Regulatory framework the final participants in this landscape are governmental entities focused on developing a regulatory framework.
Path to commercialisation
Any fusion reactor enters a very competitive energy production market, featuring with advantages such as environmentally friendly technologies and fuel abundance albeit some disadvantages in the form of high CAPEX and OPEX.
Both of the latter require significant lowering to improve the market competitiveness of planned fusion power plants by:
- developing resilient supply chains
- developing of secondary markets for fusion-related products or other methods
- development of a fusion-specific regulatory and licensing framework.
Path to commercialisation
Any fusion reactor enters a very competitive energy production market, featuring with advantages such as environmentally friendly technologies and fuel abundance albeit some disadvantages in the form of high CAPEX and OPEX.
Both of the latter require significant lowering to improve the market competitiveness of planned fusion power plants by:
- developing resilient supply chains
- developing of secondary markets for fusion-related products or other methods
- development of a fusion-specific regulatory and licensing framework.
