I was looking at another video that talks about the Oak Ridge reactor and they mentioned casually that they can use a neutron beam from the core and aim it at things. Specifically they can aim it at a running engine. Because the hydrogen in all hydrocarbon fuels are good absorbers of neutrons they can image the actual fuel as its running. They can see the flow, the turbulence, the completeness of combustion. It’s like an X-ray but the negative is formed by neutron blocking not X-ray blocking.