Why do nuclear powerplants/weapons require radioactive material?

Question

The famous E=mc2 equation seems to suggest that every atom contains great energy, not only atoms of elements that are highly radioactive and thus dangerous to handle. What barriers prevent us from using "safe" elements like iron to generate nuclear energy?

So far, I've pieced together that unstable (i.e., radioactive) atoms are "easier" to split, which explains as a practical matter why they're used in nuclear reactors.

As a theoretical matter, if you applied greater energy, could you split more stable atoms using the same basic processes as those used to split unstable atoms? For instance, if the basic process is to split an atom by pounding a particle into it, could you split a more stable atom by increasing the velocity or mass of the particle used in the collision?

Answer 1

In theory iron and anything else could be used to create energy at the rate of E=mc^2.
The only problem is : We don't know how!
We only recently (1940's) found out how to extract energy of materials that are unstable. The unstable ones are the materials like Uranium etc. Unstable material decay (they change from say Uranium to Lead) when they loose one or many proton, electron or neutron. When these particles are emitted, the material is said to be radioactive... Hence the reason for the use of radioactive material for power plants and bombs.

Answer 2

Chemical reactions like burning carbon (to make CO2) depends upon the fact that when combined, the electrons of the combination possess excess energy that can be given up as heat (exothermic reaction). The nuclei of the carbon and oxygen atoms within the CO2 molecule are unchanged.

In nuclear reactions (where nucleus stems from the word for 'nut' or center of the atom) the nut must be split (fission) or increased (fusion) to obtain excess energy. The excess energy stems from the fact that the total weight of the resulting new atom (fusion) or atoms (fission) is less that the original weight. The lost weight (or mass) called a mass defect is very small but is converted to energy per E = mc2 (which is a huge multiplier employing the square of the speed of light!). It is possible to contemplate nuclear reactions as dealing with protons and neutrons (that remain unchanged) and the 'glue' that holds them together which can be converted to energy. Think of a bag of marbles covered with sticky glue where you are able to 'burn' only the glue but only if the marbles are light (hydrogen or lithium) or very heavy and unstable (uranium or plutonium). None of the protons and neutron can be burned (and iron can not be completely used up in a reaction). Disturbing the 'nut' of an atom often produces an unstable isotope that needs to give off a particle such as a neutron, electron or proton to become stable. Since the ejected particles are energetic and 'radiate' outward the atoms are called radioactive.

Answer 3

There are two ways to get energy from atomic nuclei:
1 - You can fuse atomic nuclei together to form bigger atoms with energy being released. This is called nuclear fusion.
2 - You can split nuclei to form smaller atoms with energy being released. This is called nuclear fission.

In order to get energy from nuclear fusion, an enormous amount of energy has to be put into the atoms first, before any energy is released. Nuclear weapons have been designed using fusion. These are called hydrogen bombs. The only problem is they require a fission bomb to provide the energy needed to begin the fusion reaction. Fusion to generate power has been a research goal for many decades. So far there has been no way found to provided sufficient energy to cause nuiclear fusion in a slow and controlled process, as would be needed for a power plant.

Nuclear fission rellies on isotopes that are unstable, and split all by themselves, without having to add any energy. The trick in getting power from nuclear fission is to slow the reaction down so it doesn't go so fast that it explodes.

Answer 4

There are two kinds of nuclear reactions, fusion and fission. Today, we cannot sustain a fusion reaction in a safe and long lasting way. Maybe some day. Fission reactions involve the the deterioration of the nucleus of atoms. That only happens in radioactive materials such as uranium. In a reactor, which is just a very slow bomb, pieces of fissionable material are slowly brought together. The nuclear reactions cause heat to be generated which makes steam which turns generators making electricity. You could bring all the iron there is into close contact, and it would just sit there. You need radioactive material for a fission reaction.

Answer 5

Unfortunately there is no Star-Trek ray that you can just shine on any atom that makes it release its mc^2. There's a reason why chemists use to think that the elements were immutable; they hold onto their energy stubbornly.

There are, however, nuclear reactions that produce no radioactivity, they are just harder to use to make a practical power plant. The easiest is Deuterium - Helium-3 fusion (the opposite of fission). It produces no neutrons and can release copious quantites of energy. Unfortunately such fusion requires extremely high temperatures to obtain, which no solid vessel can contain. It's also difficult to suppress D-D fusion from happening at the same time, which does make neutrons.

Answer 6

Mostly because they are safe. There are complicated reasons for this, but as a rough, basic concept, take as a premise that lower-energy states are more stable. That means that a system "wants" to become the lowest energy state.

The more stable atoms are in the lower energy states, and won't undergo fusion or fission rapidly, so you need things that are stable enough to exist, but are unstable enough that you can easily make them decay into lower-energy/lower-mass states (the two are basically interchangeable in this case).

I can give a more detailed answer if you contact me, but I don't want to overwhelm you with complex ideas, but the short answer is that the unstable elements are the ones that we can most easily coax into decaying and losing mass, whereas the more stable ones have no reason to suddenly turn into energy.

Answer 7

The only materials which can be used to make nuclear power are things like uranium, which are radioactive.

You mention iron, which curiously is the ultimate 'end product' in nuclear reactions. Once you get to iron you can't go any further.

Nuclear fusion uses lighter elements, like deuterium or tritium. Tritium is mildly radiocative. One day it is hoped we shall use fusion power in reactors, but the technology is very complex.