On 13 August, the last undamaged spent fuel assemblies were transferred from INPP Unit 1 to the interim storage facility.
After the removal of all undamaged fuel assemblies, only the damaged fuel remains in Unit 1, which will be handled and transported to the storage facility. Currently, the damaged fuel is already handling in Unit 1, and it is important process that is being carried out for the first time at a nuclear power plant of RBMK type.
Damaged fuel – are spent fuel assemblies that have been deformed in the reactor or acquired shell defects (cracks, fissures, etc.) that have allowed direct contact of the fuel pellets with water. These defects were occurred during transportation of fuel assemblies and performing of technological operations during handling (unloading from the reactor, transferring from the reactor hall to the storage pool hall, etc.) or during storage of the fuel assemblies in the storage pools.
The management of damaged fuel is a new, technically more complex and time-intensive technological process. The safety of this process is ensured by appropriate measures, both in terms of nuclear safety and radiation protection, and in terms of the impact to the staff, population and the environment. The project of damaged fuel management work is agreed with the regulator VATESI and other responsible institutions of the Republic of Lithuania.
Upon the removal of damaged fuel from Unit 1, the damaged fuel handling equipment will be dismantled, transported to Unit 2 and assembled for the similar work.
In total, 182 damaged fuel assemblies are stored in Unit 1, and 185 – in Unit 2. It should be noted that the total number of damaged fuel assemblies stored in both units is relatively small and constitutes only 1.7% of the total number of spent fuel assemblies stored in the reactors.
All damaged fuel will be placed in 22 containers of the 190 that will be transported to the interim spent fuel storage facility.
Damaged fuel handling works on Unit 1 are to be completed in mid-August 2021, and on Unit 2 – early October 2022. Thus, by the end of 2022 it is planned to remove all fuel from both units.