What do fusion and fission have in common

Oh, one more fact for the next time you are at a party. If two atoms have the same number of protons, but different numbers of neutronsthese are isotopes like hydrogen-1 and hydrogen But back to fission. Here is the crazy part. If you break uranium into two pieces, you get krypton, barium plus two extra neutrons.

OK, that isn't crazy since all the protons and neutrons are accounted for. If you find the mass of the original uranium and the mass of all the pieces, you will find that you are missing some mass.

The stuff before has a greater mass than the stuff after. That's a little crazy. It's like spitting 2 million dollars and ending up 2 dollars short. But that energy isn't really lostit was just converted into other forms of energy. Yes, we can consider mass to be a kind of energy. This is where that famous equation comes into play. In this expression, E is the equivalent energy, m is the mass of the particle and c is a constant that happens to be the speed of light with a value of 2.

Because this proportionality constant is so large and squared , a small amount of mass can give you a HUGE amount of energy. What can you do with all of this energy you get from the change in mass? Obviously, you can heat up water and make steam.

Yes, that's usually what these reactors dothey make steam to turn a turbine to generate electricity. Just like a coal burning power plant, but without the coal. The above example looked at mass changes when you break something apart. This can also happen when you combine hydrogen and deuterium which is just hydrogen with an extra neutron. When combining low mass elements, the product has less mass than the starting stuff and you also get energy.

So, breaking large atoms gives energy nuclear fission and combining small atoms also gives energy nuclear fusion. Nuclear fission is the splitting of the nucleus of an atom into nuclei of lighter atoms, accompanied by the release of energy, brought on by a neutron bombardment.

The original concept of this nuclei splitting was discovered by Enrico Femi in —who believed transuranium elements might be produced by bombarding uranium with neutrons, because the loss of Beta particles would increase the atomic number. However, the products that formed did not correlate with the properties of elements with higher atomic numbers than uranium Ra, Ac, Th, and Pa.

Instead, they were radioisotopes of much lighter elements such as Sr and Ba. Clearly, the fission of a small amount of atoms can produce an enormous amount of energy, in the form of warmth and radiation gamma waves. When an atom splits, each of the two new particles contains roughly half the neutrons and protons of the original nucleus, and in some cases a ratio.

The explosion of a bomb only occurs if the chain reaction exceeds its critical mass. The critical mass is the point at which a chain reaction becomes self-sustaining. If the neutrons are lost at a faster rate than they are formed by fission, the reaction will not be self-sustaining. The spontaneous nuclear fission rate is the probability per second that a given atom will fission spontaneously--that is, without any external intervention. In nuclear power plants, nuclear fission is controlled by a medium such as water in the nuclear reactor.

The water acts as a heat transfer medium to cool down the reactor and to slow down neutron particles. This way, the neutron emission and usage is a controlled. If nuclear reaction is not controlled because of lack of cooling water for example, then a meltdown will occur. Nuclear fusion is the joining of two nuclei to form a heavier nuclei. The reaction is followed either by a release or absorption of energy. Fusion of nuclei with lower mass than iron releases energy while fusion of nuclei heavier than iron generally absorbs energy.

This phenomenon is known as iron peak. The opposite occurs with nuclear fission. The power of the energy in a fusion reaction is what drives the energy that is released from the sun and a lot of stars in the universe.

Nuclear fusion is also applied in nuclear weapons, specifically, a hydrogen bomb. Nuclear fusion is the energy supplying process that occurs at extremely high temperatures like in stars such as the sun, where smaller nuclei are joined to make a larger nucleus, a process that gives off great amounts of heat and radiation.

When uncontrolled, this process can provide almost unlimited sources of energy and an uncontrolled chain provides the basis for a hydrogen bond, since most commonly hydrogen is fused. Also, the combination of deuterium atoms to form helium atoms fuel this thermonuclear process.

For example:. However, a controlled fusion reaction has yet to be fully demonstrated due to many problems that present themselves including the difficulty of forcing deuterium and tritium nuclei within a close proximity, achieving high enough thermal energies, and completely ionizing gases into plasma. A necessary part in nuclear fusion is plasma , which is a mixture of atomic nuclei and electrons that are required to initiate a self-sustaining reaction which requires a temperature of more than 40,, K.

Why does it take so much heat to achieve nuclear fusion even for light elements such as hydrogen? The reason is because the nucleus contain protons, and in order to overcome electrostatic repulsion by the protons of both the hydrogen atoms, both of the hydrogen nucleus needs to accelerate at a super high speed and get close enough in order for the nuclear force to start fusion.

And because it is exothermic, the fusion of light elements is self-sustaining given that there is enough energy to start fusion in the first place. Fission reactions on the other hand is the type used in nuclear power plants and can be controlled. Atomic bombs and hydrogen bombs are examples of uncontrolled nuclear reactions. Fusion, in contrast, occurs when two or more smaller atoms fuse together, creating a larger, heavier atom.

Nuclear fusion is the reaction in which two or more nuclei combine, forming a new element with a higher atomic number more protons in the nucleus. On Earth, the most likely fusion reaction is Deuterium—Tritium reaction. Deuterium and Tritium are isotopes of hydrogen. Nuclear fission is the splitting of a massive nucleus into photons in the form of gamma rays, free neutrons, and other subatomic particles.

In a typical nuclear reaction involving U and a neutron:. Atoms are held together by two of the four fundamental forces of nature : the weak and strong nuclear bonds. The total amount of energy held within the bonds of atoms is called binding energy. The more binding energy held within the bonds, the more stable the atom. Moreover, atoms try to become more stable by increasing their binding energy.

The nucleon of an iron atom is the most stable nucleon found in nature, and it neither fuses nor splits. This is why iron is at the top of the binding energy curve. For atomic nuclei lighter than iron and nickel, energy can be extracted by combining iron and nickel nuclei together through nuclear fusion.

In contrast, for atomic nuclei heavier than iron or nickel, energy can be released by splitting the heavy nuclei through nuclear fission. The notion of splitting the atom arose from New Zealand-born British physicist Ernest Rutherford 's work, which also led to the discovery of the proton. Fission can only occur in large isotopes that contain more neutrons than protons in their nuclei, which leads to a slightly stable environment.

Although scientists don't yet fully understand why this instability is so helpful for fission, the general theory is that the large number of protons create a strong repulsive force between them and that too few or too many neutrons create "gaps" that cause weakening of the nuclear bond, leading to decay radiation. These large nucleii with more "gaps" can be "split" by the impact of thermal neutrons , so called "slow" neutrons.

Conditions must be right for a fission reaction to occur. For fission to be self-sustaining, the substance must reach critical mass , the minimum amount of mass required; falling short of critical mass limits reaction length to mere microseconds.

If critical mass is reached too quickly, meaning too many neutrons are released in nanoseconds, the reaction becomes purely explosive, and no powerful release of energy will occur. Nuclear reactors are mostly controlled fission systems that use magnetic fields to contain stray neutrons; this creates a roughly ratio of neutron release, meaning one neutron emerges from the impact of one neutron.

As this number will vary in mathematical proportions, under what is known as Gaussian distribution , the magnetic field must be maintained for the reactor to function, and control rods must be used to slow down or speed up neutron activity. Fusion happens when two lighter elements are forced together by enormous energy pressure and heat until they fuse into another isotope and release energy.

The energy needed to start a fusion reaction is so large that it takes an atomic explosion to produce this reaction. Still, once fusion begins, it can theoretically continue to produce energy as long as it is controlled and the basic fusing isotopes are supplied.

The most common form of fusion, which occurs in stars, is called "D-T fusion," referring to two hydrogen isotopes: deuterium and tritium. Deuterium has 2 neutrons and tritium has 3, more than the one proton of hydrogen.

This makes the fusion process easier as only the charge between two protons needs to be overcome, because fusing the neutrons and the proton requires overcoming the natural repellent force of like-charged particles protons have a positive charge, compared to neutrons' lack of charge and a temperature — for an instant — of close to 81 million degrees Fahrenheit for D-T fusion 45 million Kelvin or slightly less in Celsius. For comparison, the sun's core temperature is roughly 27 million F 15 million C.

Once this temperature is reached, the resulting fusion has to be contained long enough to generate plasma , one of the four states of matter. The result of such containment is a release of energy from the D-T reaction, producing helium a noble gas, inert to every reaction and spare neutrons than can "seed" hydrogen for more fusion reactions. At present, there are no secure ways to induce the initial fusion temperature or contain the fusing reaction to achieve a steady plasma state, but efforts are ongoing.

A third type of reactor is called a breeder reactor. It works by using fission to create plutonium that can seed or serve as fuel for other reactors. Breeder reactors are used extensively in France, but are prohibitively expensive and require significant security measures, as the output of these reactors can be used for making nuclear weapons as well. Fission and fusion nuclear reactions are chain reactions, meaning that one nuclear event causes at least one other nuclear reaction, and typically more.

The result is an increasing cycle of reactions that can quickly become uncontrolled. This type of nuclear reaction can be multiple splits of heavy isotopes e. Fission chain reactions happen when neutrons bombard unstable isotopes. This type of "impact and scatter" process is difficult to control, but the initial conditions are relatively simple to achieve. A fusion chain reaction develops only under extreme pressure and temperature conditions that remain stable by the energy released in the fusion process.

Both the initial conditions and stabilizing fields are very difficult to carry out with current technology. Fusion reactions release times more energy than fission reactions.

Although there are no Earth-based fusion systems, the sun's output is typical of fusion energy production in that it constantly converts hydrogen isotopes into helium, emitting spectra of light and heat. Fission generates its energy by breaking down one nuclear force the strong one and releasing tremendous amounts of heat than are used to heat water in a reactor to then generate energy electricity.