Waste management infrastructure for nuclear power plants is essential because reactors produce waste that is deadly if mismanaged.
Nuclear power plants mainly produce lower and intermediate levels of radioactive waste during regular cleaning activities, but they also produce high-level waste by burning uranium fuel.
Disposal Procedures
Lower-level radioactive waste includes contaminated equipment from nuclear power plants such as clothing, mops, and tools. It doesn’t require shielding during handling and transport and can be disposed of near the surface.
On the other hand, intermediate-level waste (ILW), which includes outer jackets of fuel rods, requires some shielding, so smaller and non-solid waste is solidified in concrete or bitumen before disposal.
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They involve immobilising waste in an insoluble cast, such as borosilicate glass, and sealing it in a material resistant to corrosion like stainless steel.
The waste is then isolated from people and the environment in a stable rock structure that is deep underground. If the repository is wet, containers are surrounded by an impermeable backfill to prevent migration of radiation.
Storage and Pre-burial Procedures
Cooling must be included before burial in the disposal procedure for high-level waste because it’s radioactive enough to increase the temperature of itself and its surroundings.
Spent fuel from nuclear reactors is placed in storage ponds made from thick reinforced concrete and steel liners. The ponds are 7 to 12 metres (23 to 39 feet) deep, allowing for several metres of water coverage that shields and cools the material.
After five years of cooling, some fuel is stored in dry casks or inside concrete shielding in vaults without air circulation.
Often, structured groups of fuel rods will be held with gas of extremely low reactivity in sealed steel casks or multi-purpose canisters. The casks and canisters may also be used as containers to transport and dispose of the spent fuel.
The used fuel is stored in a ventilated unit made from concrete and steel that can sit above or below ground.
Therefore, spent fuel waste management is performed in ways that preserve the retrievability of the material.
Reprocessing Spent Fuel
However, retrievability of high-level waste is not always a concern, since it can manifest in waste separated from reprocessed spent fuel.
Recycling used fuel involves recovering and converting spent uranium and plutonium into a mixed oxide (MOX) that can fuel reactors.
Additionally, since the leftover HLW doesn’t contain reusable material it can be disposed of without concerns about future retrieval.
Real-World Examples of Nuclear Waste Management
France is a leader in nuclear energy with around 70 percent of its electricity generated by nuclear power reactors. A major part of their waste management is recycling spent fuel.
Recycling spent fuel also requires reprocessing and MOX manufacturing plants which are expensive.
Moreover, French reactors are highly standardised meaning that a standardised spent fuel and waste management approach is applicable. Varied reactors could make waste management more complicated.
Australia and Nuclear Power
In contrast with the US and France, Australia banned nuclear power in 1998 through an amendment in the Senate.
Yet, Australia has the largest uranium reserves in the world and nuclear power is a significant source of clean energy in the turn away from fossil fuels.
Australia is also training its workforce in preparation for the operation and maintenance of nuclear submarines under the AUKUS agreement.
Several attempts to remove the ban have occurred but have been unsuccessful.
