The document discusses the scientific feasibility of integrating nuclear fusion into the energy grid by 2050. It outlines the key challenges facing magnetic confinement fusion, including achieving stable high-temperature plasma, developing materials to withstand neutron bombardment, and achieving tritium self-sufficiency. The EUROfusion roadmap is summarized, with ITER expected to demonstrate required technologies and DEMO to be the first fusion power plant producing electricity for the grid. However, overcoming challenges like plasma stability and heat exhaust will be required to realize this timeline.

1. THE SCIENTIFIC FEASIBILITY OF
INTEGRATING NUCLEAR
FUSION INTO THE ENERGY
NETWORK BY THE
MID-CENTURY
By Abidul Hoque
DECEMBER 8, 2016
UNIVERSITY OF WARWICK

2. Abidul Hoque u1431184
1
Abstract
Climate change is a pressing issue in this generation, which needs an equally overwhelming
response to tackle it. The traditional methods that supply electricity such as fossil fuels, are
generating significant greenhouse gases into the atmosphere which is contributing to global
warming. An exciting alternative to non-renewables is nuclear fusion, and it has the potential
to produce a significant proportion of clean and safe power into the energy network. Current
research show that magnetic confinement fusion is the most popular and promising method
to realise fusion energy. EUROfusion have a framework to finally integrate fusion into the
energy network; they are currently building the International Thermonuclear Experimental
Reactor (ITER) which will experiment with the largest tokamak fusion reactor in the world, and
then build the DEMO which will be the first nuclear fusion demonstration power plant that will
produce commercial energy. However, there are many technical challenges that need to be
overcome such as plasma regimes of operation, heat exhaust systems, neutron resistant
materials and tritium self-sufficiency to name a few. Realistically, after overcoming these
technical challenges, commercial energy can be expected to be introduced by 2050.
Introduction
Currently, fossil fuels account for about 80% of the primary energy demand in the world but
their impacts on the environment is unacceptable. The energy demand will only increase, and
is expected to more than double by 2050, due to the combined effects of increasing population
and energy consumption per capita. The modern society requires environmentally friendly
solutions, which can prove their long-term sustainability for energy production. Nuclear fusion
has many advantages that ensure sustainability and security of supply. The fuels required for
fusion are readily available and are virtually ‘unlimited’. There are no greenhouse gases
produced, and reactions are intrinsically safe because there is no chain reaction. With suitable
materials for the reaction chamber, radioactivity can decay within a few decades and all the
materials can even be recycled in a new reactor. [1]
Fusion energy has been expected to arrive soon for the last 40 years, so the inevitable
question arises: why is it taking so long to integrate it with the grid? The reason for the delay
is that there are still many scientific and engineering challenges to overcome. If fusion
researchers can solve these technical challenges effectively, then fusion energy will be
commercially available by the mid-century. The success of integrating fusion energy into the
grid by 2050 relies on many external factors such as the political and economic climate to
support its developments. However, this analysis will focus on its feasibility from a scientific
and engineering perspective.
Nuclear fusion reactions typically use light nuclei such as tritium and deuterium as fuel. These
positively charged nuclei normally repel each other, but they fuse if they collide fast enough to
overcome the electrostatic Coulomb force and allow the strong force to supersede. The
required speeds are obtained at very high temperatures of about 200 million degrees Celsius.
At these temperatures atoms dissolve into a gaseous mixture of charged particles called a
plasma. This hot fusion plasma must not touch the walls of the reaction chamber, so it is
therefore confined by means of a magnetic field. This method is called magnetic confinement
fusion and the technology used for this process is called a tokamak- its chamber looks like a
doughnut ring as shown in figure 1. Another method currently being researched is inertial
confinement fusion. This involves compressing a small pellet containing fusion fuel to
extremely high densities using strong lasers [2]. However, magnetic confinement fusion is
most popular and it will probably make the most significant steps towards producing
commercial energy.

3. Abidul Hoque u1431184
2
Fusion reactions yields helium nuclei and neutrons, whose energy can be harvested for
production of electricity. The reaction chamber wall in a tokamak uses a ‘blanket technology’
to absorb the energy from the bombardment of neutrons (see figure 2). This energy heats up
fluid to drive turbines to generate electricity. Fuels for fusion like deuterium is widely available;
but tritium is only available in small amounts. However, fusion reactors can produce tritium via
a reaction between neutrons and lithium. Lithium is abundant in the crust of the earth and in
the ocean. In fact, the global deuterium and lithium resources can satisfy the worlds energy
demand for millions of years! [1]
Figure 1: A schematic of a tokamak design used for magnetic
confinement fusion reactions. [1]
Figure 2: Tritium breeding blanket technology: one of several designs
developed in Europe. [1]

4. Abidul Hoque u1431184
3
There is a lot of fusion research being conducted around the world particularly with magnetic
confinement. There have been several tokamaks built such as the Joint European Torus
(JET) and the Mega Amp Spherical Tokamak (MAST) in the UK. Others include the
Experimental Advanced Superconducting Tokamak (EAST) in China. However, EUROfusion,
a consortium of national fusion research institutes in the European union and Switzerland, are
currently building, in southern France, the largest tokamak in the world which is due to be in
operation around 2020. It is called the International Thermonuclear Experimental Reactor
(ITER) and it aims to produce 10 times the energy required to run it. This will be the first major
experiment to produce a net energy gain while maintaining fusion for some prolonged time.
ITER has a goal to operate at 500MW (for at least 400 seconds continuously) from 50MW of
input power. However, no electricity will be produced from this experiment. ITER is merely just
a stepping stone for EUROfusion to introduce nuclear fusion into the energy market. The long-
term objective is to design and build a commercial fusion power plant called the DEMO. It will
mark the first step of fusion power in the energy market by supplying electricity to the grid.
However, DEMO will be built upon the ITER experience, and its expectations will largely be
dependent on the success of the goals of ITER. [1] [2]
Literature Review
The sources used in this essay, support the hypothesis that key scientific challenges must be
overcome to realise fusion energy. They provide concise and logical objectives related to the
progression of fusion energy. The information presented is clear and written from a scientific
outlook. These sources have been selected as they provide a good mixture of academic and
institutional perspectives of the scientific feasibility of fusion energy.
The report written in 2012 by EFDA, eventually succeeded by EUROfusion in 2014, provides
a clear roadmap of how fusion energy will be introduced to the market by 2050. It is a ‘living
document’ and it includes a comprehensive guide to progress fusion research, by identifying
key challenges and solutions for its mission. EUROfusion have made the most progress in
this field compared to competitors, and thus its report contains reliable conclusions for fusion
energy.
The article published by the World Nuclear Association (WNA) provides an over-arching
summary over all aspects concerned with the history and implementation of nuclear fusion. It
is a reliable source because it represents the global nuclear industry and it promotes the wider
understanding of nuclear energy.
The Magnetic-Confinement-Fusion paper provides a very detailed scientific view of fusion
energy. It goes into great detail of the physical processes that underpin fusion research. This
source is valuable to acknowledge the scientific challenges that fusion presents. It even
provides technical solutions to overcome these problems, but the implementation of these will
still need to be tested to confirm their efficiency.
These sources discussed above share a common theme: fusion energy is the long-term
solution for the grid- after 40 years of deliberation over the feasibility of fusion, the outlook is
promising, provided that some key challenges and milestones are achieved.

5. Abidul Hoque u1431184
4
Methods
EUROfusion have detailed a roadmap to the realisation of fusion electricity by 2050. This is
summarised into 3 stages of development described as below. [1]
1. Horizon 2020 (2014-2020)
 Construct ITER within scope, schedule, and cost
 Secure success of future ITER operation
 Prepare the ITER generation of scientists, engineers and operators
 Lay the foundation of the Fusion Power Plant (FPP)
2. Second period (2021-2030)
 Exploit ITER up to its maximum performance and prepare DEMO construction
3. Third Period (2031-2050)
 Complete the ITER exploitation, construct and operate DEMO
ITER is expected to complete historic milestones and demonstrate the main technologies
needed on the path to FPP. Notably, it will test robust burning plasma regimes, the test of the
conventional physics solutions for power exhaust and the validation of the breeding blanket
technology concepts.
In the European strategy, DEMO is the only step between ITER and a commercial power plant
like FPP. DEMO will benefit from the ITER experience and thus it will build upon it. The goals
of DEMO are summarised below:
 Produce net electricity for the grid at the level of a few hundred MW of power
 Breed the amount of tritium needed to close its fuel cycle
 Demonstrate suitable materials for blanket technology required to absorb the
neutron flux efficiently
 Demonstrate all technologies needed for the FPP
The roadmap described by EUROfusion provides realistic time-scales for each period of
development provided there is still the expected support and resources available. From a
purely scientific view, it will allow for sufficient research to take place, overcome any obstacles,
and allow steady progress to be made towards its goals. Nevertheless, the realisation of fusion
energy must face several technical challenges which will be discussed in some more detail.
Discussion
There are several scientific and engineering challenges that must be overcome to allow the
fruition of fusion energy by 2050. These challenges have been identified and possible
solutions have been made. [1][3]
1. Plasma must be adequately confined at very large temperatures over some space in
the tokamak. Such large temperature gradients, is precisely the main difficulty in fusion
research, because it induces some turbulence in the system [3]. This requires
minimisation of energy losses due to small-scale turbulence and the suppressing of
plasma instabilities. Plasma regimes of operation can achieve high fusion gain whilst
minimising energy losses. But, these regimes would need to be maintained in fully
steady state conditions (when the system remains unchanged even after some
transformation).

6. Abidul Hoque u1431184
5
2. The power necessary to maintain plasma at high temperatures is eventually exhausted
in some narrow region of the reaction chamber called the divertor. These Heat exhaust
systems must be able to resist large heat and particle fluxes. A solution to this consists
of reducing the heat load on the divertor targets by radiating away enough power from
the plasma, whilst minimising adverse impacts of the power output.
3. Neutron resistant materials need to be developed for the blanket to withstand the
bombardment of 14MeV neutron flux. This is because its structural and thermal
conduction properties need to be maintained properly to ensure efficient production of
electricity for DEMO. The high-speed neutrons from the fusion reactor can damage the
divertor and the blanket, so these components must be frequently replaced. To
improve efficiency of energy absorption and to reduce the frequency of replacements
it is important to develop neutron resistant materials in the future. Currently, Oxide
Dispersion Strengthened (ODS) steels and high-temperature Ferritic Martensitic (FM)
steels are under somewhat modest development.
4. Tritium is radioactive so it is best to ensure the tritium inventory is minimised as much
as possible. Tritium self-sufficiency can be achieved in a closed fuel cycle, which is a
mandatory goal for DEMO. Tritium self-sufficiency requires efficient breeding and
extraction systems to minimise its inventory. The choices of the materials and coolant
of the breeding blanket technology must be made consistently with the transformation
components of high-grade heat into electricity.
The 4 challenges presented above pose the greatest scientific and engineering challenges to
fusion researchers today. If and when these challenges are solved, and implemented, the path
to realising fusion energy is just on the horizon.
Conclusions
Magnetic confinement fusion is the most promising method that scientists have discovered
and are subsequently making united efforts to establish fusion energy into the grid by the mid-
century. EUROfusion have made the most significant progress in this field, and the upcoming
ITER, the world’s largest tokamak, will have substantial implications of the progress of fusion
energy. The operational success of ITER will determine much of the potential of later projects
like the DEMO and the final holy-grail FPP.
The technical challenges presented, pose the biggest obstacle to realising commercial fusion
energy by 2050. The destiny rests upon fusion researchers, scientists, and engineers to solve
these problems and challenges. If effective solutions are not found soon, then there will be a
probable delay in the time-scale set by EUROfusion. However, if these challenges are
overcome, and there is combined success with the operation of ITER, then access to fusion
power will be available from the grid by 2050.
References
[1] F. Romanelli et al, European Fusion Development Agreement (EFDA), 2012, Fusion
Electricity: A roadmap to the realisation of fusion energy.
[2] World Nuclear Association (2016) Nuclear Fusion Power Available at: http://www.world-
nuclear.org/information-library/current-and-future-generation/nuclear-fusion-power.aspx
(Last Accessed: 30 November 2016).
[3] J. Ongena, R. Koch, R. Wolf & H. Zohm, Nature Physics, Magnetic-confinement fusion ,12,
398–410 (2016)