Science, Tech, Math › Science Is Heavy Water Radioactive? Share Flipboard Email Print PeopleImages/Getty Images Science Chemistry Basics Chemical Laws 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 March 20, 2017 Heavy water contains deuterium, an isotope of hydrogen with a proton and a neutron for each deuterium atom. Is this a radioactive isotope? Is heavy water radioactive? Heavy water is much like ordinary water. In fact, one in twenty-million water molecules is a heavy water molecule. Heavy water is made from oxygen bonded to one or more deuterium atoms. If both hydrogen atoms are deuterium then the formula for heavy water is D2O. Deuterium is an isotope of hydrogen which has one proton and one neutron. The most common isotope of hydrogen, protium, consists of a lone proton. Deuterium is a stable isotope, so it is not radioactive. Similarly, deuterated or heavy water is not radioactive.