Abstract: Methods for acceleration of nuclear transmutation of tritium and radioactive isotopes of metals, and decontamination of metals contaminated with radioactive isotopes by destroying radioactive isotopes to a required level of residual radioactive inventory in metals with simultaneous release of thermal energy via stimulating accelerated transmutation with the half-life parameters describing kinetics of radioactive isotope destruction much shorter than their generally accepted half-life. The stimulus is applied to radioactive metals by placing them into a chamber, exposing them to gaseous substances of the group of hydrogen, deuterium, tritium, or a mixture of these isotopes in a molecular hydrogen form for said gaseous substances to be absorbed by the metals, heating the metals to a temperature of at least 200° C. and maintaining at the said temperature.