Nuclear fuel removal. Removal of a fuel element at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, USA. The fuel element and reactor head are submerged in water; the blue glow is due to Cerenkov radiation, emitted because energetic charged particles travel faster through the water than does light. The 100 Megawatt reactor produces a very high neutron flux and is used to conduct research on manmade elements heavier than Plutonium. Its principal product is the Isotope Californium252. Photographed in 1978.