Nuclear fallout is the residual radioactive material that is propelled into the upper atmosphere after a nuclear explosion. It is commonly referred to as 'nuclear rain' or 'black rain' due to its tendency to fall from the sky after the shock wave of the explosion has passed. This fallout can consist of radioactive dust and ash created by a nuclear weapon, or from a damaged nuclear plant. The consequences of nuclear fallout can be devastating, with local precipitation resulting in the early deposition of relatively large radioactive particles that are ejected by a nuclear explosion close to the surface.
Global precipitation consists of radioactivity carried by fine particles and gaseous compounds that are expelled into the atmosphere by nuclear explosions. Research suggests that charged particles emitted by Cold War-era nuclear tests may have increased rainfall thousands of miles away from test sites, triggering electrical charges in the air that caused water droplets to melt. This could have serious implications for potential targeting of nuclear fuel cycle facilities with nuclear warheads, as an air blast produces less rain than a comparable explosion near the ground. Given a specific nuclear war scenario, it is possible to use the experience gained from atmospheric nuclear tests to estimate the fate of precipitation particles on an intermediate time scale and in the long term if the atmosphere is not disturbed by smoke.
For example, it is estimated that a 50-year global catastrophic rainfall dose increases by a factor of 3 over similar estimates in which nuclear energy are not attacked. In conclusion, it is clear that nuclear fallout can have serious consequences for both local and global environments. It is important to be aware of these potential risks when considering the use of nuclear weapons or energy sources.