Despite many attempts and money invested in the last decades, the achievement of a form of controlled nuclear fusion has been essentially prohibited to date by the 'repulsive' Coulomb force between natural, positively charged nuclei that, for the fusion of two deuterons into the helium, acquires the extremely big value of 230 Newtons at the mutual distance of 1 fm. On the other hand, in nuclear physics it has been believed for about one century that negatively charged electrons and positively charged nuclei cannot form a bound state because not allowed by quantum mechanics, despite their reciprocal Coulomb attraction. Following decades of mathematical, theoretical, experimental and industrial studies, R.M. Santilli has obtained a quantitative representation of the synthesis of the neutron from protons and electrons, and of the ensuing synthesis of the so-called pseudo-nuclei, described by the laws of Hadronic Mechanics [1] according to the Einstein-Pdolsky-Rosen argument that quantum mechanics is not a complete theory.  These Pseudo-nuclei, that have a negative charge, can easily win the Coulomb barrier, being attracted instead of being repulsed by their positively charged counterparts, thus solving the above stated problem and allowing a new kind of fusion called Hyperfusion, without release of harmful radiations and fully controllable [2].

In this lecture we present some theoretical background and a review from the engineering point of view of available nuclear fusions that, even though currently limited in the amount of net energy production, are nevertheless clearly controllable and sustainable.