Fusion, unlike fission which split unstable atoms, forces together two atoms to create a new atom which has a net lower weight than the original atoms being forced together. The lost weight is not destroyed but released as energy and can be messured with the help of .
A proton has a mass of grams, a neutron grams, an electron grams, a deuterium atom grams and a tritium atom grams.
In fusion, it becomes one helium atom and one neutron. one helium atom has 2 protons, 2 neutrons, and 2 electrons.
And one Neutron.
1 tritium + 1 deuterium should be 1 helium + 1 neutron
But there is a difference of g.
so
g m/s = kg m/s
Joules/atom
That is how fusion works.
The problem is the extra neutron, but one shouldnt worry because there are plans to use sheild of non-active metals that will absorbe the neutrons and have a half life of only a few decades. Other fuels do not produce the extra neutron so they are non-polluting altogether.
These were the bare facts, make your own mind up thank you.