How Do Nuclear Power Plants Work?
Thanks to the earthquake and subsequent tsunami in Japan, the discussion and interest regarding nuclear power has exploded. Many have wondered if Fukushima Daiichi will turn into another Chernobyl or 3 Mile Island.
But what exactly is nuclear power, and how does it work? Is it as risky as the media portrays? If you were to look at some sources, information on the topic can be complicated and difficult to grasp. We wanted to present the information in a short, easy to understand layout geared for the layperson.
At their heart, nuclear power plants are essentially steam power plants. Turbines, turned by intense steam pressure, generate usable electricity which is created from the heat resulting from nuclear fission reactions in the core. That same water used to power the turbines also serves as a coolant for the radioactive material, preventing it from overheating and melting down.
The Uranium Core
The core of a plant – the part that generates heat – contains 200 or so 12 foot long rods that are packed with uranium 235 pellets. These rods are then added to a fuel assembly. The fuel rods are then bombarded with neutrons which break apart the uranium 235 atoms. A process known as nuclear fission.The nuclear fission taking place in the rods creates large amounts of energy. This heat energy is used to pressurize steam to move the turbines which creates electricity.
A large downside to nuclear power is the radioactive waste. It’s not a substantial amount, but it does pose some some interesting challenges. This waste needs to be isolated from our ecosystem for at least 100,000 years before it deteriorates due to natural radioactivity.
The spent fuel (which is a small pellet roughly the size of your fingertip) is first placed in a pool of water and allowed to cool down. Due to radioactivity, they remain hot for 20 to 40 years. Once they cool, it’s off to long term storage. This waste is then moved hundreds of meters underground in concrete bunkers for radioactivity containment and for further isolation from the environment.
Being stored underground safely for 100,000 years sounds risky, largely because humans have never signed on to something that long term before. However, there are examples of radioactive containment happening naturally on earth. Earth’s own naturally formed nuclear reactors deep in the crust have been chugging along for at least 1.7 billion years.
- Nuclear power plants actually give off less radiation than coal-burning power plants.
- Except for the Chernobyl plant in the Ukraine, nuclear power plants have not caused a single known death. The death toll from the Chernobyl incident is less than 50.
Feel free to check out the video below which provides some more visuals on the operation of a nuclear power plant.