1. Nuclear energy, when released, can make a huge impact on nature and people around it. A bomb for instance, could kill a lot of people. Terrorists can harness a nuclear weapon and make it a very powerful threat against countries they dislike.
2. Nuclear power plants are easy targets for terrorist attacks, because they cannot withstand the force of a plane hitting them.
3. Where and how to store nuclear waste is a big problem. The waste constantly gives off a high level of radiation, which is harmful to the ecosystem. Nuclear waste will stay radioactive for hundreds of thousands of years before it returns into a harmless material.
4. It takes a lot of money and time to build a nuclear power plant. A power plant can take 10 years to build and it may cost around $2 billion. The U.S. has 109 nuclear reactors. So, the U.S. has spent roughly $218 billion just for nuclear reactors!
5. A nuclear power plant can have a meltdown or overheat, and the radioactive materials may explode. They are placed in big metal boxes, but even that can't stop an explosion. There have been many problems like this in the past, like the Chernobyl accident in 1986, and the Fukushima accident as recent as 2011.