Abstract: An apparatus and method for sourcing nuclear fusion products uses an electrochemical loading process to load low-kinetic-energy (low-k) light element particles into a target electrode, which comprises a light-element-absorbing material (e.g., Palladium). An electrolyte solution containing the low-k light element particles is maintained in contact with a backside surface of the target electrode while a bias voltage is applied between the target electrode and an electrochemical anode, thereby causing low-k light element particles to diffuse from the backside surface to an opposing frontside surface of the target electrode. High-kinetic-energy (high-k) light element particles are directed against the frontside, thereby causing fusion reactions each time a high-k light element particle operably collides with a low-k light element particle disposed on the frontside surface. Fusion reaction rates are controlled by adjusting the bias voltage.