18.1.1 Origins of radioactive waste

While one might expect that ‘radioactive waste’ should be easily defined, the IAEA3 offers three separate definitions. The first is adequate here:

For legal and regulatory purposes, waste that contains, or is contaminated with, radionuclides at concentrations or activities greater than clearance levels as established by the regulatory body.

This definition recognises that, because all matter is radioactive to some degree, it is necessary to define a level above which it becomes ‘officially radioactive’ and subject to regulation. Radioactive waste exists in many forms and is present in virtually every country of the world. In describing its origins, it is convenient to place countries into one of three groups:

1 those with no nuclear power plants (NPPs)

2 those with NPPs

3 those with NPPs and other fuel cycle facilities

Wastes in the absence of nuclear power

In countries with no nuclear industry, radioactive waste will mostly consist of disused sealed sources. Typically, the number of sealed sources in store in a medium-sized developing country will be a few thousands. If a country has oil, gas or mineral deposits then it is likely that some wastes will be in the form of naturally occurring radioactive material (NORM). Often this is produced as so-called ‘pipe scale’: radium-rich mineral deposits that form inside pipework used to transport process water. The level of activity is generally quite low — perhaps up to a few thousand Bq/g — and it can be removed by water jetting and removed as sludge. This allows the pipes to be reused or released as scrap. In some cases it may be possible to pump the sludge underground: back into the formations from whence it came. More usually, the material is dried, drummed and put in storage awaiting a permanent solution. Finally, countries in this first group may also possess one or more low-power research reactors. Without exception, these are donated by some other country, often with an agreement that the spent fuel will be repatriated when the reactor is decommissioned.