The concept of a chain reaction was first introduced by Hungarian-American chemist George de Hevesy and German physicist Friedrich Paneth in 1914 while studying radioactive transformations. They noted that the decay of uranium atoms could set off a series of subsequent radioactive decays, creating a 'chain reaction.'

However, the application of chain reactions to energy production is often attributed to Enrico Fermi and a team of scientists during the Manhattan Project, specifically in relation to harnessing nuclear energy and the development of the first nuclear reactor in 1942.