Part 1 of 3 Parts
     One of the main arguments against nuclear power is the continued accumulation of highly radioactive spent nuclear fuel. Until there is a permanent disposal solution, much spent nuclear fuel will have to be stored temporarily. Many commercial nuclear power reactors around the world are approaching the end of their operational lives and temporary storage of spent nuclear fuel is becoming critical.
     When the useful nuclear fuel in a fuel rod has been consumed, the fuel rods have to be removed from the reactor. They are hot and radioactive which requires that they spend a few years in a cooling pool to allow cool them to cool the point where they can be handled. They can then be left in the cooling pools for temporary storage or they can be removed from the pool and placed in dry casks made of steel and concrete.
      Leaving spent nuclear fuel in cooling pools is widely practiced. This has the benefit of not having to remove the spent fuel for external storage. It has the drawback of taking up space in the cooling pools. There is so much spent nuclear fuel stored in cooling pools around the world that some nuclear reactors may have to be shut down because there is no room left in the cooling pools. 
     Some countries are working on a closed fuel cycle in which spent fuel is reprocessed and recycled in a wet environment. Some countries store all their spent nuclear fuel in wet conditions until it is cool enough for final disposal. Some countries remove the fuel from the cooling pools as soon as it is cool enough to be handled and place it in dry casks on site or at external temporary storage facilities. Wet storage has been used for decades and obviously works but external dry storage is becoming more popular. It still needs to prove that it is safe and reliable.
      Wet storage is an interim storage method where spent nuclear fuel remains in cooling pools at least long enough to dissipate some of its heat and shorter-lived radioactivity which would permit its temporary storage or permanent disposal in dedicated facilities.
      Rebecca Weston is the chief operating officer of the Sellafield nuclear facility the U.K. Sellafield is a large multi-function nuclear site close to Seascale on the coast of Cumbria, England. Activities at the site include nuclear fuel reprocessing, nuclear waste storage and nuclear decommissioning, and it is a former nuclear power generating site.
     Weston told the 2020 International Atomic Energy Agency Scientific Forum that the U.K. is currently constructing Advanced Gas Reactors (AGR). These are the second generation of gas-cooled reactors developed in Britain following the earlier I Magnox gas-cooled reactors.
     As part of the Nuclear Decommissioning Authority (NDA) in the U.K., Sellafield has been involved in the development and construction of thermal oxide reprocessing plants receipt and storage ponds. They have been reconfigured to be an interim storage solution for keeping spent nuclear fuel in the U.K. The AGR fuel will be stored there for the next eighty years. Wet storage supports the U.K, spend nuclear fuel storage strategy that their NDA has developed.
Please read Part 2 next