What is nuclear energy?


Comparing to renewables

In: Physics

Nuclear energy is energy contained within the nuclei of atoms. Currently, we can only harness the energy of large nuclei, but we may eventually be able to also utilize small nuclei which are far more abundant. In either case, a fuel is required and rather large/complex containment systems used, as well as tight safety regulations. Nuclear power is able to provide quite a lot of energy, but has drawbacks including limited downscaling, radioactive waste (albeit in small quantities), nuclear proliferation, and expensive infrastructure.

There are two forms of nuclear energy; one is using the same process that powers stars (fusion) and the other exploits the energy from past star explosions (fission). Both involve liberating energy from the nucleus of atoms and are *extremely* powerful. However, they’re basically “one way” energy processes…once you fuse or split (fission) atoms, you can’t recover them without putting in more energy than you got out in the first place.

“Renewables” refers to energy sources that are, at least from the point of view of Earth, self-regenerating. If we dam a river and use that to power a hydroelectric dam, as long as we don’t let more water out each year than the river refils, it lasts “forever”. Similarly, wind, tidal, or solar don’t “use up” anything that doesn’t get automatically get replaced at regular intervals.

All renewable power sources we know about rely on the sun as their ultimate source so they don’t literally last “forever” but they’ll last so long that it’s functionally forever to us.

However, nuclear power is so energetic that even the supplies of uranium (fission) and hydrogen (fusion) that we know about are also functionally “forever” so it’s kind of a wash in that sense when compare to coal or oil or gas, which are most definitely finite over realistic timelines.

Current nuclear energy is the energy created during a nuclear fission reaction. When big unstable atoms split into smaller ones they release a ton of energy.

Compared to renewables the pros are it has a much more consistent/reliable output, has a higher output for the cost and space used, takes less carbon to set up and use, and creates very little waste.

For the cons, in the event of a failure they are extremely dangerous, though failures are way less common than most people believe, it takes a big starting investment to set up, the waste it creates can be hard to store safely, and they currently can’t make profitable small versions for less populated areas.

Nuclear energy usually refers to fission, where we split apart large, unstable atoms into smaller atoms and some energy. It’s not technically a renewable energy source, but the fuel used doesn’t have any other better human uses, and its end products don’t contribute to industrial climate change.

It can produce radioactive materials that need to be disposed of safely, but there’s ways to do fission that supporters say is much safer, like thorium salt reactors.

The kind of nuclear energy we use to generate electricity is called “fission”. It comes from the energy that is released when you break an atom apart. Atoms are made of protons, neutrons, and electrons. Electrons and protons don’t stick together very strongly, and so electrons can usually be separated from protons without much fuss (and that’s actually what you’re doing when you make electricity). But protons and neutrons stick together really hard and they are difficult to separate. But if you can do it, they release *lots* of energy in the form of heat. We use that heat to boil water and make steam, and that steam spins a turbine that generates electricity.

Virtually all forms of power plant are ultimately just using something to spin a turbine which is what generates the electricity. Wind power just uses the wind to spin the turbine. Hydroelectric uses falling water to spin the turbine. Tidal power uses rising and falling tides to pump water through a turbine. The only one that doesn’t is photovoltaic solar panels. Instead, they use a chemical reaction that occurs between some materials when they are exposed to certain types of light. That reaction releases some of the electrons in the materials, which generates electricity.

Wind and solar have the problem of being inconsistent. It’s hard to control how much wind is blowing, or how much sun is shining at any given time. Hydroelectric sources are better about this because you can get pretty consistent water flow through systems like that. However, most large dams that can be built in the developed world have already been built. So there’s not much room for expansion there. The benefit of nuclear energy is that it’s extremely consistent, controllable, reliable, and generates no air pollution. It does generate radioactive waste, which is a problem, and if not done properly nuclear power has the potential to be dangerous (though far less dangerous than fossil fuels have been).

At the end of the day, both renewable and nuclear power could potentially provide viable sustainable clean energy for the world. The question is really do we want to spend our time, money, and efforts on solving the consistency and control problems of renewables, or the radioactive waste problem of nuclear. It seems at this point that most of the world has chosen the former.