Cherenkov Radiation and the “Blue Glow” Often, these beta particles are emitted with such high kinetic energies that their velocities exceed the speed of light (3.0×108 meters per second) in water. When this occurs, photons, seen to the eye as blue light, are emitted and the reactor core “glows” blue.

New, unused fuel rods can be touched, they’re not that radioactive. Here’s one: It consists of uranium dioxide, and it emits alpha radiation, which cannot penetrate the skin. It isn’t exactly healthy, so you should not touch it … but it isn’t that unsafe.

Today, nuclear power technicians use the amount of blue glow, or Cherenkov radiation, in a reactor to gauge the radioactivity of spent fuel rods.

The short answer to your question is “no,” radioactive things do not glow in the dark – not by themselves anyway. Radiation emitted by radioactive materials is not visible to the human eye. It is also possible to “trick” radioactive material into creating visible light. This is called Cherenkov radiation.

Any charged particle moving faster than light through a medium emits Cherenkov radiation. The w e a k speed of a charged particle can exceed the speed of light. …

This animated plutonium rod should not be confused with the inanimate carbon rod, which does not glow. Radioactive materials such as uranium and plutonium do not, by themselves, glow. These materials can glow without an external power supply, because the atomic transitions can be excited by the radioactive decay.

Plutonium-239 is virtually nonexistent in nature. It is made by bombarding uranium-238 with neutrons in a nuclear reactor. Uranium-238 is present in quantity in most reactor fuel; hence plutonium-239 is continuously made in these reactors.