Reactor inside

This is the view of the top of the reactor (yellow on right) and the entire structure in which it's housed. At only about 15 inches wide, the reactor itself is tiny compared with commercial power plants. It's held in a tank of heavy water, which reflects neutrons back into the core to maintain nuclear fission, or atom splitting. That tank is covered in graphite; then in a layer of a special kind of concrete; then in metal shielding. Photography in the facility is restricted to certain areas and specific angles for security reasons.