Although it is arguably for the benefit of society, the translation of basic nuclear processes into technological achievements produces nuclear wastes that can become environmental hazards if they are not properly cared for. Light‐element fusion, heavy‐element fission and radioactive decay have provided us with nuclear weapons, nuclear power plants and nuclear medicine. But they all produce radioactive materials that are unusable, no longer needed, or unwanted. Ultimately, these materials require long‐term isolation from the biosphere.