Krypton

Krypton (Kr) is one of five Rare or Noble Gases that find use because of their lack of reactivity and ability to support light. It is a product of the fission of uranium, and atmospheric Krypton exists as several stable isotopes. Shorter half-life isotopes are produced from off-gassing of nuclear fuel rods, and from atmospheric detonations of nuclear weapons from the 1940’s until the early 1960’s.

Krypton exists in the atmosphere at a concentration of about 1.1 part per million (ppm) by volume. It and Xenon (Xe) collect in the oxygen fraction in an air separation plant. Because of their higher boiling points, both Krypton and Xenon remain as condensed liquids as oxygen boils. In larger air separation plants, this fraction is collected for further purification and distillation.

Krypton, like the other gases produced from cryogenic distillation, is recovered at purities of 99.99% and higher. Most Krypton is used in long life / high intensity light bulb applications, and Krypton, in mixtures with other rare gases, is usually found in all “neon” lighting systems; the addition of other gases provides the varying colors of red, green, yellow, blue and violet as well as a brilliant white that we associate with these lights. It is also used in gas mixes in excimer laser applications and some medical gas mixes. Krypton is used as an insulator in specialized glass applications.