LILW (Low and Intermediate Level radioactive Waste)   Low level Waste (LLW) is generated from hospitals and industry, as well as from the nation's nuclear fuel cycle. This waste comprises paper, rags, tools, clothing, filters and other items  which contain small amounts of mostly short-lived radioactivity. It has been often compacted or incinerated before disposal . Intermediate level Waste (ILW) contains higher amounts of radioactivity and some requires shielding. It typically comprises resins, chemical sludges and metal fuel cladding, as well as contaminated materials from reactor decommissioning. It may be solidified in concrete or bitumen for disposal.

Radioactivity arises naturally from the decay of particular forms of some elements, called isotopes. Some isotopes are radioactive, most are not, though in this publication we concentrate on the former. Different types of radiation require different forms of protection:

Alpha radiation cannot penetrate the skin and can be blocked out by a sheet of paper, but is dangerous in the lung.

Beta radiation can penetrate into the body but can be blocked out by a sheet of aluminium foil.

Gamma radiation can go right through the body and requires several centimetres of lead or concrete, or a metre or so of water, to block it.
All of these kinds of radiation are, at low levels, naturally part of our environment. Any or all of them may be present in any classification of waste.