Many people consider nuclear power to be the future of alternative energy, the solution to climate change and creating a sustainable future. Others think of nuclear power as far too dangerous and risky to be worth any potential benefits. So how can we determine how safe nuclear power is? Well, the first step is to examine how it works…
How do power plants in general create electricity?
Most power plants use some sort of fuel to create heat which then boils water. This water vaporizes into steam, which is then used to turn a big turbine (as shown below).
This turbine spins, creating mechanical energy, and is attached to a generator which turns this energy into electricity. Both coal-based power plants and nuclear power plants work this way, but the type of fuel they use is different. Coal-fired plants burn coal to release heat that generates steam. Nuclear power plants, on the other hand, use nuclear fission.
Everything is made up of atoms, which in turn are made up of a nucleus, the “center” of the atom that contains protons (positively charged) and neutrons (not charged), and electrons (negatively charged), which exist in the space surrounding the nucleus. Nuclear fission involves splitting an atom, releasing a lot of energy, that is then used to heat the water in the power plant.
During fission reactions, atoms (typically radioactive atoms like uranium, which are very big and therefore easier to break apart) are hit with lone neutrons, causing the atom to split and release more neutrons. The atom splits because, when the atom comes in contact with the free neutron, it incorporates the neutron into the atom, causing the atom to destabilize and break apart. Those neutrons that are released then conduct other fission reactions with other atoms, creating a chain reaction. To prevent the reaction from spinning out of control, the power plant also has control rods that can absorb free neutrons and stop the reaction if needed.
A picture of a nuclear fission reaction, found at: http://commons.wikimedia.org/wiki/File:Kernzerfall.svg
How is a nuclear power plant set up?
The uranium must be enriched, and then it is set up into rods and bundles of rods that are put inside water to prevent them from melting during the reaction. Then, it heats up that water and turns it into steam, which then goes through a tube to heat up other water that then interacts with the turbine and turns it (so the radioactive materials never go near the turbine itself).
It it Dangerous?
These reactions can release radiation, which comes in multiple different forms. Some radiation is high energy electrons being released from the reaction, some is high-energy protons. There are multiple levels of safety measures taken at any nuclear power plant, including making the containment vessel coated in steel and two levels of concrete protecting the vessel.
The radioactive waste definitely does have to be taken care of safely, and there is still a debate going on about exactly how to best ensure the safety of everyone when disposing of the waste.
In the next few posts, we will look at the problems at Chernobyl and Fukushima, and exactly how safe nuclear power really is in comparison to current types of energy production.