WNA reports in summary:
- Radioactive wastes are stored so as to avoid any chance of radiation exposure to people, or any pollution.
- The radioactivity of the wastes decays with time, providing a strong incentive to store high-level waste for about 50 years before disposal.
- Disposal of low-level waste is straightforward and can be undertaken safely almost anywhere.
- Storage of used fuel is normally under water for at least five years and then often in dry storage.
- Deep geological disposal is widely agreed to be the best solution for final disposal of the most radioactive waste produced.
Most low-level radioactive waste (LLW) is typically sent to land-based disposal immediately following its packaging for long-term management. This means that for the majority (~90% by volume) of all of the waste types produced by nuclear technologies, a satisfactory disposal means has been developed and is being implemented around the world.
For used fuel designated as high-level radioactive waste (HLW), the first step is storage to allow decay of radioactivity and heat, making handling much safer. Storage of used fuel may be in ponds or dry casks, either at reactor sites or centrally. Beyond storage, many options have been investigated which seek to provide publicly acceptable, safe, and environmentally sound solutions to the final management of radioactive waste. The most widely favored solution is deep geological disposal. The focus is on how and where to construct such facilities.
Used fuel that is not intended for direct disposal may instead be reprocessed in order to recycle the uranium and plutonium it contains. Some separated liquid HLW arises during reprocessing; this is vitrified in glass and stored pending final disposal.
Intermediate-level radioactive waste (ILW) that contains long-lived radioisotopes is also stored pending disposal in a geological repository. In the USA, defence-related transuranic (TRU) waste – which has similar levels of radioactivity to some ILW – is disposed of in the Waste Isolation Pilot Plant (WIPP) deep geological repository in New Mexico. A number of countries dispose of ILW containing short-lived radioisotopes in near-surface disposal facilities, as used for LLW disposal.
Some countries are at the preliminary stages of their consideration of disposal for ILW and HLW, whilst others, such as Finland and Sweden, have made good progress in the selection of publicly acceptable sites for the future disposal of radioactive waste.
The following table sets out the commonly accepted disposal options. When considering these, it should be noted that the suitability of an option or idea is dependent on the wasteform, volume, and radioactivity of the waste. As such, waste management options and ideas described in this section are not all applicable to different types of waste.
Commonly-accepted disposal options:
- Near-surface disposal at ground level, or in caverns below ground level (at depths of tens of metres) LLW and short-lived ILW
Implemented for LLW in many countries, including Czech Republic, Finland, France, Japan, Netherlands, Spain, Sweden, UK, and USA.
Implemented in Finland and Sweden for LLW and short-lived ILW. - Deep geological disposal (at depths between 250 m and 1000 m for mined repositories, or 2000 m to 5000 m for boreholes)
- Long-lived ILW and HLW (including used fuel) Most countries have investigated deep geological disposal and it is official policy in several countries.
Implemented in the USA for defence-related truansuranic waste at WIPP. Preferred sites selected in France, Sweden, Finland, and the USA.
Geological repository site selection process commenced in the UK and Canada. - Additional ideas have also been considered and discounted in the past (see section on Other ideas for disposal below, and information paper on International Nuclear Waste Disposal Concepts).
Near-Surface Disposal
The International Atomic Energy Agency (IAEA) definitions of this option is the disposal of waste, with or without engineered barriers, in:
- Near-surface disposal facilities at ground level. These facilities are on or below the surface where the protective covering is of the order of a few metres thick. Waste containers are placed in constructed vaults and when full the vaults are backfilled. Eventually they will be covered and capped with an impermeable membrane and topsoil. These facilities may incorporate some form of drainage and possibly a gas venting system.
- Near-surface disposal facilities in caverns below ground level. Unlike near-surface disposal at ground level, where the excavations are conducted from the surface, shallow disposal requires underground excavation of caverns. The facility is at a depth of several tens of metres below the Earth's surface and accessed through a drift. The term near-surface disposal replaces the terms 'shallow land' and 'ground disposal', but these older terms are still sometimes used when referring to this option.
These facilities will be affected by long-term climate changes (such as glaciation) and this effect must be taken into account when considering safety, as such changes could disrupt these facilities. This type of facility is therefore typically used for LLW and short-lived ILW with half-lives of up to 30 years.
Near-surface disposal facilities at ground level are currently in operation in:
- UK – LLW Repository at Drigg in Cumbria operated by UK Nuclear Waste Management (a consortium led by Washington Group International with Studsvik UK, Serco, and Areva) on behalf of the Nuclear Decommissioning Authority.
- Spain – El Cabril LLW and ILW disposal facility operated by ENRESA.
- France – Centre de l'Aube operated by Andra.
- Japan – LLW Disposal Center at Rokkasho-Mura operated by Japan Nuclear Fuel Limited.
- USA – five LLW disposal facilities: Texas Compact facility near the New Mexico border, operated by Waste Control Specialists; Barnwell, South Carolina operated by EnergySolutions; Clive, Utah (EnergySolutions); Oak Ridge, Tennessee (EnergySolutions); and Richland, Washington – operated by American Ecology Corporation. Near-surface disposal facilities in caverns below ground level are currently in operation.
- Sweden – the SFR final repository for short-lived radioactive waste at Forsmark, where the depth of the facility is 50m under the Baltic seabed – operated by the Swedish Nuclear Fuel and Waste Management Company (SKB).
- Finland – an underground repository at Olkiluoto for LLW and ILW has been in operation since 1992. A similar facility at Loviisa was commissioned in 1997. The depth of these is about 100 meters (600 feet).
Original working URL: https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-waste/storage-and-disposal-of-radioactive-waste.aspx
Media coverage: https://www.tri-cityherald.com/opinion/opn-columns-blogs/article240247301.html
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