It is not entirely clear from your question what it is you really want to know about.
If it is man made, plutonium is prepared by human beings in nuclear reactors and recycling plants.
We usually find that uranium is used as fuel in nuclear reactors (though some use plutonium).
Plutonium, most likely, a man-made element, but mined Uranium will also do.
A very small amount of plutonium is found in nature. The majority of it is produced artificially.The majority of plutonium is made in nuclear reactors:uranium-238 captures a neutron, becoming uranium-239uranium-239 undergoes beta decay, becoming neptunium-239 (halflife 23.5 minutes)neptunium-239 undergoes beta decay, becoming plutonium-239 (halflife 2.33 days)plutonium is then chemically separated from the remaining uranium, neptunium, etc.
An atomic bomb is made up from the inside out by: a plutonium pit(ball) about the sized as a honeydew melon. surrounded by about 2 inches of high explosive on all sides. This is triggered in a USA bomb by an intricate series of safety triggers that prevent accidental explosion by altitude triggers, timers, and arming triggers. Excess nuclear binding energy supplied by the strong nuclear force.
nuclear chemicals such as plutonium
plutonium and neutrons
Uranium, plutonium or hydrogen.
If it is man made, plutonium is prepared by human beings in nuclear reactors and recycling plants.
You don't need nuclear power, energy can be generated using other methods, fossil fuels, hydro-electric etc. However nuclear power does reduce a countries reliance on fossil fuel, which can be particularly important for countries with few fossil fuel reserves of their own. Nuclear power stations do not release CO2 into the atmosphere so do not directly contribute to global warming. Many countries are looking at an investment in nuclear power to help meet CO2 emissions targets. Nuclear power stations are also required to make plutonium for nuclear weapons. Plutonium does not occur naturally and can only be made from uranium in nuclear reactors. Any country with a nuclear weapons program will have a civilian nuclear power industry for this reason.
When it comes to heavy elements that are used in weapons and in reactors, uranium and plutonium are both candidates. The first atomic bombs were made of uranium, and they are now pretty much made of plutonium. Some special nuclear reactors are powered by plutonium fuel, but most reactors for power generation use (enriched) uranium for fuel. Links are provided to relevant articles posted by our friends at Wikipedia, where knowledge is free.
For example plutonium is a nuclear fuel; also the isotope 233U.
We usually find that uranium is used as fuel in nuclear reactors (though some use plutonium).
most cannot, as to produce weapons grade plutonium the fuel cycle must be made very very short. however soviet RBMK reactors and the US hanford N reactor were designed explicitly to produce both electric power and weapons grade plutonium.
You don't need nuclear power, energy can be generated using other methods, fossil fuels, hydro-electric etc. However nuclear power does reduce a countries reliance on fossil fuel, which can be particularly important for countries with few fossil fuel reserves of their own. Nuclear power stations do not release CO2 into the atmosphere so do not directly contribute to global warming. Many countries are looking at an investment in nuclear power to help meet CO2 emissions targets. Nuclear power stations are also required to make plutonium for nuclear weapons. Plutonium does not occur naturally and can only be made from uranium in nuclear reactors. Any country with a nuclear weapons program will have a civilian nuclear power industry for this reason.
The waste from nuclear reactors can in principle be reprocessed to extract plutonium, which can be used to fuel nuclear reactors. But this is not "renewable" it is just recycling fuel the reactor made, this process can at best multiply the amount available reactor fuel by roughly 100 times, then we run out. Only France reprocesses their nuclear waste, other countries have abandoned it largely from the unjustified fear that reprocessed plutonium reactor fuel might be "stolen" to build atomic bombs (normal power reactor generated plutonium has very high levels of the undesired plutonium-240 and plutonium-241 which make it impossible to build working atomic bombs with that plutonium).
Plutonium is obtained in nuclear reactors:U-238(n,gamma).................U-239(beta)...................Np-239(beta).................Pu-239