Disclosed is a method of Deuterium fusion and more particularly, a fail-safe, controlled bubble fusion reactor producing a power output of electricity and heat. It is self contained having 3 internal main chambers and externally mounted computer and electric power output terminals. Internal Chamber A contains devices for removing gases and solids, storage of fresh and spent liquid, pump and heat exchanger, pressure regulator and check valve, and sensors. Chamber B contains circulated pure liquid D2O within which are mounted a pair of parallel electroacoustical piezoelectric quartz crystal transducers with a narrow reaction gap between supplied with transducer energies of ultra-sonic sound plus amplitude modulated UHF EM. A cycled gap sonic pressure wave creates small bubbles which absorb both gap energies so as to cycle through radius increases during the negative portion of the energies cycle and then violent collapse during the positive portion of the energies cycle to a very small radius in 2 stages. During end of final stage, a collapsing spherical bubble produces a spherical shock wave allowing ''selective resonant tunneling'' through the Coulomb barriers of pairs of adjacent Deuterium nuclei resulting in fusion. Chamber C contains 2 RF generators and some electronics for controlling the fusion reaction. External computer provides electronic fail-safe oversight, visual touch-screen display of system functions for monitoring and making adjustments, and manual by-pass fail-safe override push switch.