The used fuel assemblies that were damaged during a chemical cleaning process at Hungary's Paks nuclear power plant in 2003 have been transported to Russia for processing.
Irradiated fuel from unit 2 of the Paks plant suffered damage from overheating on 10 April 2003 when water circulation in a nuclear fuel washing tank was inadequate. The assemblies overheated in the cleaning tank, which was submerged in the transfer pond, so that most became deformed with burst cladding, releasing radioactive material into the water and noble gases into the plant area. The cleaning tank was designed, manufactured and operated by France's Framatome ANP. The event was categorised at Level 3 on the International Nuclear Events Scale.
Paks 2 - a Russian-supplied VVER-440 - was shut down at the time its fuel was removed for washing, but did not restarted until 30 December 2006 due to the complications posed by the stranded damaged fuel.
Russia's TVEL won an international tender for restoration work at Paks 2. The removal of the damaged fuel was completed in January 2007.
The 30 damaged fuel assemblies have now been transported by rail to the Mayak processing plant near Chelyabinsk in the Urals ""where it will be further processed," Rosatom announced today. It said that the removal of the fuel was carried out according to a number of intergovernmental agreements between Russia and Hungary.
Paks currently comprises four Russian-supplied VVER-440 pressurized water reactors, which started up between 1982 and 1987. Though originally 440 MWe gross, the units have been upgraded and will be modified further to give 500-510 MWe gross. In 1999, the plant signed a fuel supply contract with TVEL that will run throughout the life of the units, until around 2037.
In early 2014, Hungary and Russia signed a cooperation agreement which included the construction of two new VVER reactors of up to 1200 MWe each at Paks. The first new unit is to be commissioned in 2023, with the second following about two years later. Russia is also to supply fuel for the new units.
Researched and written
by World Nuclear News