Intro To Challenge
Definition-Fusion Also called nuclear fusion- a thermonuclear reaction in which
nuclei of light atoms join to form nuclei of heavier atoms, as the combination of
deuterium atoms to form helium atoms
--Fusion power is a theoretical form of power generation in which energy will be
generated by using nuclear fusion reactions to produce heat for electricity
generation. In a fusion process, two lighter atomic nuclei combine to form a
heavier nucleus, and at the same time, they release energy.
---fusion is the energy source for the sun
Human-engineered fusion has been demonstrated on a small scale. The
challenge is to scale up the process to commercial proportions, in an efficient,
economical, and environmentally benign way.
Half-life (t1⁄2) is the time required for the amount of something to fall to half its
initial value. The term is very commonly used in nuclear physics to describe how
quickly unstable atoms undergo decay, or how long stable atoms survive,
radioactive decay, and it is also used more generally of any type of exponential or
non-exponential decay. The converse of half-life is doubling time.
-The theoretical idea behind the employment of nuclear fusion as an energy
source is that light atomic nuclei combine to release energy. This energy comes
from the difference in mass between the input material and the products of the
reaction. The total mass of the reactants’ nuclei is slightly larger than the mass of
produced nuclei. This excess mass is converted into energy, the amount of which
can be described by Einstein’s famous rest energy equation E=mc , which is a
consequence of special relativity.
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Graphic representation of a D-T reaction ( H + H --> He + n + 17.59 MeV Energy)
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Societal Impact
-The fuel for fusion is abundantly available. Two isotopes of hydrogen are well suited
for fusion: deuterium and tritium. Deuterium is available from seawater (and can be
extracted by electrolysis) and it is expected that tritium can be produced within a
fusion power station from small quantities of lithium.
-Some of the greatest benefits that fusion reactors present are fuel abundance and
accessibility. Deuterium is a stable isotope and naturally occurs in place of
hydrogen. In fact, it constitutes a small fraction of hydrogen in water. Quantitatively,
it exists in great amounts and is virtually unlimited, taking into account how much
water there is on planet Earth.
-The second constituent of the reaction, is an unstable isotope and, for that reason, is
much less abundant then Deuterium and quite rarely occurs naturally. However, this
problem can be solved by a reactor design that produces Tritium during the reaction,
and such design does exist. The nuclear reaction of Deuterium with Tritium produces
a neutron. If the reaction space is confined inside a lithium blanket, the neutrons
produced in the primary reaction will engage a secondary reaction with lithium,
producing Tritium. The lithium supply is also virtually unlimited, since lithium is the
third most abundant element in the universe after hydrogen and helium.
-There is a significant correlation between oil price and support for fusion research
-Fusion has the unique capability to provide utility-scale energy on-demand
wherever it is needed, making it an excellent complement for intermittent
renewables and battery storage. Combined, these technologies make for a practical
energy portfolio that mitigates climate change while driving economic prosperity.
it is not harmful for the environment and safety risks associated with its storage and
handling are minimal Because of the low energy available to drive an accident and
the low hazard to be released in the event of an accident
History of Work-to-Date
-During the late 1940s and early ’50s, research programs in the United States,
United Kingdom, and the Soviet Union began to yield a better understanding of
nuclear fusion, and investigators get on ways of exploiting the process for
practical energy production. Fusion reactor research focused primarily on using
magnetic fields and electromagnetic forces to contain the extremely hot plasmas
needed for thermonuclear fusion. These plasmas proved very difficult to get at
the temperatures needed to form energy. This is because the hot gasses escape
through the magnetic structure. In the 1950s the plasma physics theory was
incapable of describing the behavior of the plasmas.
-In 1958 the research went from classified to public. In 1961 the idea of inertial
confinement fusion was proposed. This idea was kept classified until the 1970s.
Through the early 1980s they continued their research on this topic. They
attempted to employ large pulses of laser energy to implode and shock-heat
matter to temperatures needed for nuclear fusion to occur. The research group
has made significant progress through years of sophisticated work to design and
develop short pulse, high power lasers that are arcuate for millimetre-sized
targets. Although they have not been able to create fusion reactors, the necessary
conditions of plasma temperature and heat insulation have been largely
achieved. This suggests that fusion energy for electric-power production is very
possible. The finished product of a successful fusion power systems must be
capable of producing electricity safely and in a cost-effective manner, with a
minimum of radioactive waste and environmental impact.
Current state of practice and conversation
-There are a number of conditions that need to be satisfied in order to facilitate a
fusion reaction. The reactants’ nuclei need to have enough kinetic energy (or,
roughly speaking, speed) to overcome the electrostatic force, which causes the
positively charged nuclei to repel. The combining nuclei need to get in the vicinity
of each other where the strong nuclear force will overcome the electromagnetic
force. In macroscopic terms, this means that the gas of the reacting material has
to be heated to a certain temperature before fusion can occur. That temperature
is on the order of 100 million degrees Kelvin
-In the 21 century however The dream of nuclear fusion is on the brink of being
realised, according to a major new US initiative that says it will put fusion power
on the grid within 15 years.
-The project, a collaboration between scientists at MIT and a private company,
will take a radically different approach to other efforts to transform fusion from
an expensive science experiment into a viable commercial energy source. The
team intend to use a new class of high-temperature superconductors they predict
will allow them to create the world’s first fusion reactor that produces more
energy than needs to be put in to get the fusion reaction going.
-Bob Mumgaard, CEO of the private company Commonwealth Fusion Systems,
which has attracted $50 million in support of this effort from the Italian energy
company Eni, said: “The aspiration is to have a working power plant in time to
combat climate change. We think we have the science, speed and scale to put
carbon-free fusion power on the grid in 15 years.”
Future Directions
- Tritium has a very short half-life of only 12 years, as compared to the materials
used in fission reactors, for which the half-life approaches thousands of years.
This makes fusion fuel much safer than that of fission or even fossil fuel power
plants.
-Finally, the waste products of fusion reaction are either much safer than those of
other kinds of power plants, or are absolutely harmless. The discussed reaction of
Deuterium with Tritium, as can be seen in Fig. 2, produces the regular isotope of
helium and a neutron. It is the same isotope of helium that is used to fill air
balloons which is not radioactive and cannot activate the equipment. However,
the neutrons, although not radioactive themselves, are capable of activating the
reactor’s structure, especially the metallic parts, when they hit them at high
speed. This effect can be mitigated by using less reactive materials (carbon fiber
has been proposed), which will produce short half-life waste. In contrast, even
regular materials activated by high energy neutrons have a half-life of only about
30 years or less which is much less than the half-life of nuclear waste produced
by fission. So, no complex storage would be required.
-the parts should hold for approximately 40 to 50 years (the lifetime of a regular
power plant of any kind)
Nuclear fusion reactor
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