What does HLW mean in UNCLASSIFIED

High Level Waste (HLW) refers to highly radioactive materials generated from the use or reprocessing of nuclear fuel. These materials are primarily composed of fission products such as cesium, strontium, iodine, and uranium isotopes. Generally speaking, any material with a high enough radioactive intensity that requires special disposal measures is considered HLW.

Nuclear reactors generate heat through controlled nuclear reactions for energy production. During this process a variety of radioactive substances are created which constitute HLW. Other sources of HLW include fuel reprocessing plants as well as research facilities where spent nuclear fuel is stored.

In many countries around the world, HLW is stored in enclosed concrete and steel containers known as dry casks or vaults. These containments are designed to minimize leakage and diffusion of radiation while providing secure storage for extended periods of time.

Currently there are limited options available for permanently disposing of HLW due to its hazardous nature and long-term toxicity; however some countries have begun utilizing deep geological repositories or surface storage sites in order to safely contain this type of waste in an environmentally responsible manner.

Exposure to high levels of radiation can cause severe burns, cancer, genetic mutations and other illnesses in people who are exposed over long periods of time or at close proximity to doses higher than what is deemed safe or acceptable according to international standards