I'm just dropping in and didn't really read the rest of the back and forth between you two. But fusion and fission reactors result in neutron Flux. In fission energy and neutrons are released when atoms of fissile material in the fuel matrix split apart. In fusion reactions, hydrogen atoms fuse into helium, and energy and a neutron are released. When there are neutrons passing through a measure of space, you have a Flux. And high energy neutron Flux can activate certain materials when they pass through said Flux