What is nuclear energy ? Term nuclear is referred to the nucleus, which is the central part of an atom surrounded by electrons contain most of its mass. According to the Einstein formula " E = MC 2 " if the nucleus of an atom is split-ed in two then a certain amount of that atoms mass is converted into energy. History 1895 Roentgen discovers X-rays ,1898 The Curies identify 2 radioactive nuclides, coin term "radioactive“ 1899 Rutherford distinguishes alpha and beta radiation and discovers half-life, 1909 Rutherford discovers that most mass is concentrated in a small nucleus.1920 Rutherford theorizes a "neutron“ .1935 Chadwick identifies neutrons .1938 Hann and Strassman split uranium atoms with neutrons, Meitner and Frisch explain what's happening and name it "fission“ 1939 Fermi and Szilard measure neutron multiplication, conclude that a nuclear chain reaction is possible .1939 Szilard, Wigner, and Teller convince Einstein to sign a letter wa