Abstract: A method for producing energy from nuclear reactions between hydrogen and a metal, includes a) production of a determined quantity of micro/nanometric clusters of a transition metal, b) bringing hydrogen into contact with the clusters and controlling its pressure and speed; c) creating an active core for the reactions by heating the clusters up to a temperature that is higher than the Debye temperature TD of the metal; d) triggering the reactions by a mechanical, thermal, ultrasonic, electric or magnetic impulse on the active core, causing the atoms of the metal to capture the hydrogen ions, with liberation of heat; and e)removing the heat maintaining the temperature above TD.