Nuclear Fusion – Definition, Process, Reactions and Energy

It is a process in which two or more light nuclei collide to create a heavier nucleus. Elements like hydrogen that have a low atomic number undergo nuclear fusion. The reverse of nuclear fusion is the nuclear fission process in which heavy atoms disperse and produce lighter elements. Nuclear fusion and fission both generate enormous amounts of energy because some of the mass of the fusing nuclei is transformed into energy throughout the reaction, and the matter is not preserved. 

Nuclear Fusion Process

A fast neutron and a helium atom are created when deuterium and tritium combine, respectively. The two heavy isotopes combine again to form a helium atom and a neutron, converting their extra mass into kinetic energy.

For the nuclear fusion process, the involved nuclei must be brought together. The goal is to get them so near that the nuclear forces start to work and fuse the nuclei.

Nuclear Fission

Nuclear fusion is the process of creating energy by joining atomic nuclei together rather than breaking them (as with fission). No long-term radioactive waste or greenhouse gases are produced during this process, which occurs naturally in the stars’ centres like the Sun.

Like fission power plants, fusion plants use heat from atomic reactions to heat water, make steam, power turbines, and generate electricity. However, it has proven difficult to establish the necessary conditions in fusion reactors without requiring more energy than is created.

A fusion reactor, also known as a tokamak, employs a gas, often deuterium, an isotope of hydrogen that can be recovered from seawater. High heat and pressure cause the deuterium atoms’ electrons to break free, forming a plasma. Strong magnetic fields are required to confine this plasma since it may reach temperatures of at least 100,000,000°C. Plasma is a superheated, ionised gas. Although these temperatures are ten times higher than those in the Sun’s core, they are necessary for the process because the gravitational pressure needed for it cannot be produced by the Sun itself. The heated plasma particles clash as auxiliary heating devices raise the temperature to the levels needed for fusion.

Nuclear Fusion Reaction

The fusion processes between the lightest elements that result in the formation of Helium are also necessary for the practical generation of fusion energy. Deuterium (D) and tritium (T), the heavy isotopes of hydrogen, react more effectively with one another, and when they fuse, they produce more energy per reaction than two hydrogen nuclei. One proton makes up the hydrogen nucleus. Tritium has one proton and two neutrons, while the deuterium nucleus has one proton and one neutron.)Because of a crucial aspect of nuclear matter called the binding energy, which may release through fusion or fission, fusion processes between light elements and fission events that divide heavy atoms release energy. 

The nucleus’s binding energy serves as a gauge of how effectively its nucleons are bonded together. Consider an element that has N neutrons and Z protons in its nucleus. The element has an atomic number of Z and an atomic weight A of Z + N. The binding energy B is the energy associated with the mass differential between the nucleons bound together (Z + N) in a nucleus of mass M and the Z protons and N neutrons when regarded individually. The equation is:

                                        B = (Zmp + Nmn − M)c2

Where c is the speed of light and mp, and mn is the masses of the proton and neutron. Experimental research has shown that the binding energy per nucleon reaches a maximum of around 1.4 1012 joules at an atomic mass of about 60 or roughly the atomic mass of iron. As a result, the net energy released by the fusion of elements lighter than iron or the splitting of heavier ones is usually positive.

Both nuclear fusion and nuclear fission reactions

Fission separates two heavy, unstable atomic nuclei into two lighter nuclei, which also releases energy but to a lesser extent than fusion. Fusion is the process of two light atomic nuclei combining and releasing energy. 

Fusion is a far more powerful process than fission because it releases more energy. Nuclear fusion is less risky than nuclear fission because fusion generates waste fuel rods that contain radioactive material that is toxic enough to be used in weapons and must be kept carefully for a very long time; both nuclear fusion and nuclear fission reactions produce a great amount of energy.

Nuclear Fusion energy

Nuclear fusion energy power plants instead call for additional heat since it is hard to duplicate the kind of pressure that permits fusion to happen naturally in the Sun’s core. It takes more energy to generate the 150–300 million °C of heat needed for fusion to occur than it does for fission.

Nuclear Fusion example

Here are some of the Nuclear fusion examples –

Hydrogen bomb

A hydrogen bomb is one of the prime nuclear fusion examples; The thermonuclear bomb is another name for the hydrogen bomb, or “h bomb.” When compared to atomic bombs, these bombs have more destructive force. Nuclear fusion events led to the creation of these hydrogen bombs. Nuclear fusion is a process that causes an uncontrolled chain reaction that is self-sustaining at high temperatures. 

There are two primary parts to nuclear fusion weapons: Uranium-235 and/or Plutonium-239 make up the bulk of the initial stage. A different nuclear fusion secondary stage uses deuterium, tritium, or lithium deuteride as fuel. Isotopes of hydrogen-like deuterium and tritium offer the perfect interacting nuclei for fusion. Lithium-6 deuteride is now employed as a fuel for weapons.

Nuclear fusion energy in the Sun

Nuclear fusion keeps all of the stars in the cosmos, including nuclear fusion in the Sun, alive. They create a significant quantity of heat and energy through this process. Any star’s core experiences extremely high pressure, which is where nuclear fusion reactions occur. For instance, the Sun’s core temperature is around 15 million degrees Celsius. When two hydrogen isotopes, Deuterium and Tritium, combine to generate Helium at this temperature and extremely high pressure, a tremendous quantity of energy is released in the form of heat. In nuclear fusion in the sun, some 600 million tonnes of hydrogen are transformed into Helium per second. Nuclear fusion is shown by the processes that occur in the Sun.

Nuclear fusion in stars

The nuclear fusion reaction in star reactions occurs in the cores, which are responsible for their immense luminosity. The energy originated in nuclear fusion in stars through helium fusion, proton-proton fusion, or even the carbon cycle, depending on the age and mass of a star. Heavy elements up to iron may fuse briefly toward the conclusion of a star’s bright lifetime; since the iron group is near the apex of the binding energy curve, fusion of elements heavier than iron would instead involve energy absorption. Although the iron group represents the maximum limit for fusion’s ability to produce energy, higher atoms are produced in stars via a different class of nuclear events.

Frequently Asked Questions 

1. Is Energy Produced by Fusion or Fission Greater?

Fusion generates more energy than fission, but it has faced difficulties since the energy required to establish the conditions for fusion has been more than the energy generated. Fusion has the potential to generate several times as much energy as fission when these difficulties are completely overcome.

2. Does radioactive waste come from nuclear fission and fusion?

There is some radioactive waste produced by both fusion and fission. However, fusion doesn’t produce any long-term nuclear waste, whereas fission power plants produce unstable nuclei; Helium, an inert gas, is produced as part of the standard fusion process, while tritium is produced and consumed inside the reactor. Tritium is radioactive since it is a beta emitter, but because it is only used in very small doses and has a short half-life, it does not provide a significant risk.

3. Why not employ nuclear fusion?

Since nuclear fusion is expensive and difficult to replicate and regulate, it is not currently employed for power generation. High temperatures are necessary for positively charged nuclei to collide and fuse without being severely repulsed by electrostatic forces. To solve these difficulties, nevertheless, work is still being done.

4. What are some nuclear fission and fusion?

When two low-mass isotopes come together under incredibly high heat and pressure, fusion takes place. This frequently happens when the deuterium (hydrogen-2) and hydrogen isotopes tritium (hydrogen-3) combine to form an isotope of Helium and an additional neutron. This isotope fusion produces energy at a rate several times greater than fission while avoiding long-term radioactive byproducts.

The target nucleus used in the majority of nuclear reactors is uranium-235. Accelerating a neutron into this nucleus can split the atom into two smaller isotopes (known as “fission products”) and three more neutrons, releasing a significant amount of energy in the process. Other uranium-235 atoms engage in subsequent fission events as a result of the neutrons that are emitted. The energy generated is utilised to spin turbines in a generator to create electricity by heating water into steam, both nuclear fusion and nuclear fission reactions produce a great amount of energy.