By my understanding practically all of the generated energy is due to neutrons hitting the containment vessel. Highly energetic neutron, impacting solid matter, will generate quite a bit of heat in the violent collision.<p>I found one fairly decent source [0] which goes into somewhat greater detail. It&#x27;s worth noting that if you follow the link to first page of the series, that page explicitly states that what fusion reactors call &quot;neutron flux&quot; would be called &quot;heat flux&quot; in traditional reactors.<p>And it makes sense even when thinking logically. Energy and matter are interchangeable, and the reactor turns matter into energy; majority of matter escaping from the fusion reactor will be helium and neutrons. These particles interacting with external solid matter turns kinetic energy into heat. That&#x27;s the power plant&#x27;s heat source.<p>Now, as to the fraction of heat transferred by neutrons compared to that transferred by the newly formed helium - I have no idea.<p>0: <a href="http:&#x2F;&#x2F;www.visionofearth.org&#x2F;industry&#x2F;fusion&#x2F;how-do-we-turn-nuclear-fusion-energy-into-electricity&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.visionofearth.org&#x2F;industry&#x2F;fusion&#x2F;how-do-we-turn-...</a>