Government policy dictates whether certain materials – such as used nuclear fuel and plutonium – are categorized as waste.
Every radionuclide has a half-life – the time taken for half of its atoms to decay, and thus for it to lose half of its radioactivity.
Radionuclides with long half-lives tend to be alpha and beta emitters – making their handling easier – while those with short half-lives tend to emit the more penetrating gamma rays.
Eventually all radioactive waste decays into non-radioactive elements.
The more radioactive an isotope is, the faster it decays.
Radioactive waste is typically classified as either:
- Low-level (LLW), which is generated from hospitals and industry, as well as the nuclear fuel cycle. It comprises paper, rags, tools, clothing, filters, which contain small amounts of mostly short-lived radioactivity.
- Intermediate-level (ILW), due to its higher levels of radioactivity, requires some shielding. It typically comprises resins, chemical sludges, metal fuel cladding, as well as contaminated materials from reactor decommissioning.
- High-level (HLW) requires cooling and shielding. It has both long-lived and short-lived components, depending on the length of time it will take for the radioactivity of particular radionuclides to decrease to levels that are considered non-hazardous for people and environment. HLW is the focus of significant attention regarding nuclear power, and is managed accordingly.
The IAEA estimates that 370,000 tonnes of heavy metal (tHM) in the form of used fuel have been discharged since the 1st NPPs commenced operation.
Of this, the agency estimates that 120,000 tHM have been reprocessed.
The IAEA estimates that the disposal volume of the current solid HLW inventory is approximately 22,000m3.
For context, this is a volume roughly equivalent to a three metre tall building covering an area the size of a soccer pitch.