What is a cold fusion reactor?

A cold fusion reactor is a vessel in which nuclear fusion takes place at or near room temperature. Normally, fusion requires incredible amounts of heat, enough to make it far too dangerous to attempt on Earth. As of 2014, no known method of achieving cold fusion exists.

Fusion is the reaction that drives the sun and other stars. Under intense pressure and heat, atoms crash into each other and form new elements from the fusion of their particles. This process releases enormous amounts of energy, which is why scientists have attempted to develop a nuclear fusion technique that does not require or produce millions of degrees of excess heat.