User:Rkjaouha/sandbox

Nuclear fusion is the process in which atoms from two different nuclei come close enough to the point where they fuse into one nuclei. This process can take many different forms. Nuclear fusion can come in three different forms, a proton-proton chain, a deuterium-deuterium reaction, and a deuterium-tritium reaction. Currently nuclear fusion is not used to generate energy. Instead, we use nuclear fission which is the process in which we split an atom into two or more atoms. The reason nuclear fusion is not currently used to generate energy is because it has not yet been discovered how to maintain the reaction and not allow it to expand beyond what we can control. Nuclear fusion would create a cleaner more efficient power source than nuclear fission currently does, this power source would also be unlimited and cheaper.

In the 1930s, fusion of atoms was discovered by scientists and since then they have tried to gain a better understanding of how they can replicate this energy into a contained system. In the 1940s scientists discovered that replicating the environment for fusion would require containing the energy within a system that can handle millions of degrees of heat. In the 1950s we found that nuclear fusion itself had no applications in military power and therefore the U.S. began working with the USSR to gain a better insight into nuclear fission.

In the late 1980s scientists claimed to have discovered something known as cold fusion. This allows us to have nuclear fusion at room-level temperatures when certain conditions are met. Cold fusion is still under-developed and something the scientific community has yet to acknowledge as feasible because of its inconsistency.

Types of Fusion

There are two general types of the nuclear fusion, the original "Hot" fusion and the newer cold fusion. The general idea of each is still to create a nuclear fusion reaction, although the method is somewhat different between the two.

Thermonuclear fusion

The Sun is a common basis for nuclear fusion, in which hydrogen atoms collide to form a consistent form of energy.

Thermonuclear fusion is a type of fusion that we can observe within our stars and throughout the universe. It consists of temperatures within the hundreds of millions of degrees to keep the process of nuclear fusion stable. Regular nuclear fusion that can found in our stars is also known as thermonuclear fusion. This type of fusion has yet to be contained in a way that is useful to us. Studying for Thermonuclear fusion began around 50 years ago when it was first discovered. Since then we've made many new discoveries, but have yet to maintain control of this type of environment. In regular nuclear fusion we can find that mass amounts of energy are produced when two nuclei collide, while at the same time the number of nucleons and electronic charge are conserved seen in the formula below.

${\ce {^4He + ^14N -> ^17O + ^1H}}$

Cold Fusion

Cold fusion is a hypothetical form of fusion that was researched in the late 1980s. It describes a fusion reaction feasible at room level temperatures, although it is regarded by the scientific community as unstable and an inconsistent phenomenon.

Cold fusion isn't an actual developed principle, rather it is something that was developed in theory by Martin Fleischmann and Stanley Pons. These two scientists asserted that they had created a scenario that produced excess heat they believed could only be created in terms of nuclear processes. What Martin and Stanley found was that using an experiment involving the electrolysis of heavy water on the surface of a palladium electrode would cause a reaction that produced excess heat. They asserted after this discovery that the only explanation for this excess heat was that a fusion reaction must have occurred. This theory was eventually deemed unrepeatable as scientists failed to replicate the findings. Though some research continues today, the scientific community has not succeeded in finding similar results in their experiments, and thus the phenomenon is considered inconsistent.

Types of Reactions

Some different types of reactions normally occur in fusion reactions, these reactions are normally based on Hydrogen atoms interacting with other atoms to produce some sort of energy.

Proton-Proton Chain Reaction

Basis of a proton-proton reaction that is commonly seen in stars.

The Proton-Proton Chain is a common set of fusion reactions that is the primary source of energy in stars such as the sun. The reactions transform mass-1 hydrogen isotopes into helium. The proton-proton chain was first proposed in 1926 by Arthur Eddington in his book Internal Constitution of the Stars.

The chain begins with two common reactions, followed by a set of possible branches of reactions. First, two mass-1 hydrogen isotopes combine to form a hydrogen-2 nucleus, while emitting a positive electron and a neutrino.

${\ce {^1H + ^1H -> ^2H +e^+ + \nu}}$

This is followed by the absorption of another hydrogen-1 nucleus, forming a helium-3 nucleus, and the emission of a gamma ray.

${\ce {^2H + ^1H -> ^3He + \gamma}}$

In the main branch, the final reaction involves the fusion of two Helium-3 nuclei formed by the previous two reactions. They form a helium-4 nucleus and eject two protons.

${\ce {^3He + ^3He -> ^4He + ^1H + ^1H}}$

Deuterium-Deuterium Reaction

Deuterium-Deuterium Reaction, also known as Deuterium Fusion, is a process that occurs in stars. This process involves a deuterium nucleus and a proton combining to form a helium-3 nucleus. This can be seen as a second stage of the original proton-proton reaction, as the two protons that originally fused, fuse once again with another proton. This reaction can be defined using the formula below:

${\ce {H + H -> He + n + 3.27MeV}}$

This can also be viewed as with another formula in which only hydrogen atoms react:

${\ce {^2H + ^2H -> ^3H + ^1H + 4.03MeV}}$

Deuterium-tritium reaction

The Deuterium-tritium reaction exists within the deuterium cycle of fusion. This reaction is the most useful of the four hydrogen fusion reactions, as it gives us the most energy output at 17.59 MeV. The formula for this type of fusion involves the combination of two Hydrogen atoms to create a Helium atom and a lone neutron. This formula can be presented as:

${\ce {^2H + ^3H -> ^4He + ^1n + 17.59MeV}}$

like many of the other fusion examples this fusion can go further, after the first step it can be mixed again with another hydrogen atom to create even more energy:

${\ce {^2H + ^3He -> ^4He + ^1H + 18.3MeV}}$

All of this is under the hypothetical scenario that we can correctly replicate the conditions under which this type of reaction can be maintained. These conditions are something that we can define under a principle known as Lawson's criterion.

History

1930s

In the 1930s scientists including Hans Bethe began to realize that nuclear fusion was possible and that it was the process that occurs in the sun.

1940s

By the 1940s researchers began to look for ways to control fusion reactions to make them a stable energy resource on earth. In this early stage researchers used something known as magnetic confinement because the temperatures required were too much to maintain. At this point in time, thermonuclear research was conducted primarily for military applications and creating weapons like the H-Bomb and other bombs.

1950s

Research changed in the 1950s when researchers found that controlled fusion research had no promising military applications compared to fission.

1960s

In the 1960s researchers hoped to use the new invention of the laser to contain these fusion reactions. This became known as inertial confinement. Researchers continued experimenting with many different devices throughout the 1960s to find a solution to the problem. In the following decade, U.S. researchers agreed to concentrate efforts one device known as the tokamak, a containment device invented in the Soviet Union.

1980s and 1990s

The tokamak was found to grow at a fast pace, but in the 80s and 90s it was found that many different forms of maintaining nuclear fusion were progressing at a much faster rate, with even better results. In 1989, Martin Fleischmann and Stanley Pons introduced a new report in which they stated that they have developed a method of creating fusion reactions at room temperature scenarios. Immediately after many journalists and media enterprises began talking about their discovery and it's potential to change how physicists thought about the world. Soon after many physicists began challenging the original research stating that the scientists report consisted of bad scientific behavior and didn't follow normal principles.

2000s

Narrowing down research of fusion reactions proved to be troublesome and in 2012 the former head of the U.S fusion energy program even wrote about the issues that were caused with limiting the research that was being undertaken. Since the fallout with the cold fusion report, many researchers who choose to study cold fusion have began to lose respect. However, with the death of Fleischmann in 2012, the debate stirred once again as many researchers tried to replicate and prove his theory that fusion reactions can occur at room level temperatures.

See Also

• Nuclear fission
• Tokamak
• Nuclear fusion
• Physics
• Energy
• Sustainable
• reactions

References