melts are produced in the screen of isotopes in animal original
alpha_emitter is radioactive_isotope. radioisotope is not isotope. plutonium_239 is isotope. radioisotope is isotope. californium_252 is isotope. californium_252 is not isotope. radioactive_isotope is not isotope. plutonium_239 is not isotope. radioactive_isotope is isotope.