uses+of+radioactivity

__Nuclear Weapons:__ Obviously, the first thing that comes to mind when thinking about how nuclear energy is used is nuclear weapons. These devices are either seen as the scourge of mankind or the number one deterrent of the Cold War, depending on one's perspective. Research stemming from the development and testing of nuclear weapons has led to countless applications in the civilian world.

__Nuclear Power:__ The first civilian nuclear power plant was up and running in Russia in 1954. Since then, nuclear power went through a boom and bust, the latter due to accidents at Three Mile Island and Chernobyl. Today, there are 436 plants operating in 31 different countries around the world, generating 15% of the world's electricity.

__Spacecraft:__ Some satellites and spacecraft use radioisotope thermoelectric generators to produce electricity.

__Medical:__ The use of X-rays has become commonplace in health care today. Other uses include radioactive isotope tracing, where a radiotracer is placed in the body and tracked to study blood flow, tumor location, etc. Some cancer treatments use radiation therapy, such as the 'gamma knife'.

__In the Home:__ The only place you will find radioactive elements in the home will be in a smoke detector, which uses americium-241. Some homes may contain radon-222 gas, which seeps up from the ground naturally.