Atoms can lose or gain energy as an electron moves from an outermost to an innermost orbital around the nucleus. However, dividing the nucleus of an atom releases a much greater amount of energy than that generated by the movement of the electron on a lower orbital. The division of the atom is called nuclear fission and a series of consecutive fissions is called a chain reaction. Obviously, it is not an experiment that can be done at home; nuclear fission is only possible in a laboratory or a nuclear power plant, both of which are properly equipped.
Steps
Method 1 of 3: Bomb the Radioactive Isotopes
Step 1. Choose the right isotope
Some elements or isotopes of the elements are subject to radioactive decay; however, not all isotopes are the same when the fission process begins. The most common isotope of uranium has an atomic weight of 238, is made up of 92 protons and 146 neutrons, but its nucleus tends to absorb neutrons without breaking down into smaller nuclei than other elements. The uranium isotope with three fewer neutrons, 235U, is much more susceptible to fission than 238U; this type of isotope is called fissile.
- When uranium splits (undergoes fission), it releases three neutrons which collide with other uranium atoms, creating a chain reaction.
- Some isotopes react too quickly, with a speed that prevents the maintenance of a continuous chain fission. In this case, we speak of spontaneous fission; the isotope of plutonium 240Pu belongs to this category, unlike 239Pu which has a lower fission rate.
Step 2. Get enough isotope to make sure the chain reaction continues even after the first atom has split
This means having a minimum amount of fissile isotope to make the reaction sustainable, that is, a critical mass. Achieving critical mass requires sufficient isotope base material to increase the chances of achieving fission.
Step 3. Collect two nuclei of the same isotope
Since it is not easy to obtain free subatomic particles, it is often necessary to force them out of the atom they belong to. One method is to make the atoms of a given isotope collide with each other.
This is the technique used to create the atomic bomb with 235U which was launched on Hiroshima. A gun-like weapon collided atoms of 235U with those of another piece of 235U at a speed sufficient to allow the released neutrons to spontaneously strike other nuclei of atoms of the same isotope and divide them. As a result, the neutrons released by the splitting of atoms hit and split other atoms of 235U and so on.
Step 4. Bomb the nuclei of a fissile isotope with subatomic particles
A single particle can hit an atom of 235U, dividing it into two atoms of different elements and releasing three neutrons. These particles can come from a controlled source (such as a neutron gun) or are generated by the collision between nuclei. The subatomic particles generally used are three:
- Protons: are particles with a mass and a positive charge; the number of protons in an atom determines which element it is.
- Neutrons: They have mass, but no electric charge.
- Alpha particles: these are the nuclei of the helium atoms deprived of the electrons that orbit around them; they are composed of two neutrons and two protons.
Method 2 of 3: Compress the Radioactive Materials
Step 1. Obtain a critical mass of a radioactive isotope
You need a sufficient amount of raw material to make sure the chain reaction continues. Remember that in a given sample of an element (plutonium for example) there are more than one isotope. Make sure you have correctly calculated the useful amount of fissile isotope contained in the sample.
Step 2. Enrich the isotope
Sometimes, it is necessary to increase the relative amount of a fissile isotope present in the sample to ensure that a sustainable fission reaction is triggered. This process is called enrichment and there are several ways to do it. Here are some of them:
- Gaseous diffusion;
- Centrifuge;
- Electromagnetic isotope separation;
- Thermal diffusion (liquid or gaseous).
Step 3. Squeeze the sample tightly to bring the fissile atoms closer together
Sometimes, atoms spontaneously decay too quickly to be bombarded with each other; in this case, compressing them strongly increases the probability that the released subatomic particles collide with other atoms. This can be achieved by using explosives to forcibly bring the atoms of 239Pu.
This is the method used to create the bomb with 239Can be dropped on Nagasaki. Conventional explosives encircled the mass of plutonium and, when detonated, compressed it carrying the atoms of 239It is so close to each other that the released neutrons have continued to bombard and divide them.
Method 3 of 3: Divide the Atoms with the Laser
Step 1. Enclose the radioactive materials in the metal
Put the sample in a gold liner and use a copper holder to secure everything in place. Remember that both fissile material and metals become radioactive when fission takes place.
Step 2. Excite electrons with laser light
Thanks to the development of lasers with power of the order of petawatts (1015 watts), it is now possible to split atoms using laser light to excite electrons in the metal that encloses the radioactive substance. Alternatively, you can use a 50 terawatt (5 x 1012 watts) to achieve the same result.
Step 3. Stop the laser
When electrons return to their orbitals, they release high-energy gamma radiation that penetrates the atomic nuclei of gold and copper. In this way, the nuclei release the neutrons which in turn collide with the uranium atoms present in the metal coating and thus triggering the chain reaction.
Advice
This technique can only be performed in physics laboratories or nuclear power plants
Warnings
- Such a procedure could trigger a large-scale explosion.
- As always when using any type of equipment, follow the necessary safety procedures and do not do anything that seems dangerous.
- Radiation is deadly, wear personal protective equipment and keep a safe distance from radioactive material.
- Attempting to perform nuclear fission outside the designated premises is illegal.
