Undamaged fuel assemblies were removed from Ignalina NPP in August (Photo: INPP)The last assemblies of undamaged used nuclear fuel have been removed from the first unit of the Ignalina Nuclear Power Plant (INPP) and transferred to the intermediate storage, INPP has announced.

Work will now begin to remove 367 damaged assemblies stored at the INPP site – the first time such an operation has been carried out at a nuclear power plant with an RBMK reactor. 

The damaged fuel comprises assemblies that, while they were in the reactor, became deformed or acquired cladding defects which allowed direct contact between fuel pellets and water. These defects were incurred during transportation of fuel assemblies and performing technological operations during their handling (when unloading from the reactor, moving from the reactor hall to the fuel pool hall, etc.) or during storage of fuel assemblies in the used fuel pools.

The project for handling the damaged fuel has been agreed with the nuclear regulator, VATESI, and other responsible state institutions.

Once the damaged fuel has been removed from Ignalina unit 1, the handling equipment will be dismantled, transported to unit 2 where it will be installed to perform similar work. A total of 182 damaged fuel assemblies are stored at unit 1 and 185 at unit 2. The total number of damaged fuel assemblies stored at both units is relatively small, accounting for only 1.7% of all the fuel assemblies stored at the reactors.

All damaged fuel will be placed in 22 containers out of 190, which will be transported to the interim used nuclear fuel storage facility. Work on handling the damaged fuel at unit 1 should be completed by mid-August 2021, and at unit 2 by the beginning of October 2022.

Ignalina comprises two 1500MWe RBMK reactors and support facilities. Ignalina 1 was shut down in 2004 and unit 2 in 2009 as a condition for Lithuania’s accession to the European Union.

Photo: Undamaged fuel assemblies were removed from Ignalina NPP in August (Photo: INPP)