Radiation coming from somewhere other than the item in front of you: streaming through a penetration or shield gap, scattering off walls, or arriving from a neighbouring system. Skyshine is radiation scattered back down from the air above an unroofed source. Techs talk about shine when an area reads higher than its own components justify, and they find it by moving the meter and watching the reading rise toward the real source.
That's shine from the letdown heat exchanger through the wall sleeve, shield the sleeve, not the pump.
If a reading climbs as you back away from a component, the dose is coming from somewhere else, and that is shine.
Related terms
Shielding
Material placed between a radiation source and people to absorb radiation and reduce dose rate.
Background
The ever-present radiation from natural and other sources that an instrument reads when no source of interest is near.
Hot spot
A small spot on piping or equipment with a much higher dose rate than its surroundings.
Time, distance, shielding
The three basic ways to cut external dose: spend less time near a source, stay farther away and put material in between.