Science, Tech, Math › Science Nuclear Radiation Definition Share Flipboard Email Print Nuclear radiation may refer to light, heat, or energetic particles emitted by nuclear decay, fission, or fusion. Ian Cuming / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 16, 2020 Nuclear radiation refers to the particles and photons emitted during reactions that involve the nucleus of an atom. Nuclear radiation is also known as ionizing radiation or ionising radiation (depending on the country). The particles emitted by nuclear reactions are sufficiently energetic that they can remove electrons from atoms and molecules and ionize them. Nuclear radiation includes gamma rays, x-rays, and the more energetic portion of the electromagnetic spectrum. Ionizing subatomic particles released by nuclear reactions include alpha particles, beta particles, neutrons, muons, mesons, positrons, and cosmic rays. Nuclear Radiation Example During the fission of U-235 the nuclear radiation that is released contains neutrons and gamma ray photons. Sources Woodside, Gayle (1997). Environmental, Safety, and Health Engineering. US: John Wiley & Sons. ISBN 978-0471109327.