The spent fuel assemblies removed from the VVER reactors of the nuclear power plants are “after-cooled” for several years (3-5 years in Jaslovské Bohunice, 6-7 years in Mochovce) in storage pools located in the vicinity of the reactors. Subsequently they are transported into the Interim Spent Fuel Storage Facility (ISFS) in Jaslovské Bohunice, where they are and will be properly stored for a few decades, until the back-end of management of spent nuclear fuel is authorized and implemented.

The Interim Spent Fuel Storage Facility currently operating in Jaslovské Bohunice stores the fuel assemblies in a pool filled with water (so-called wet storage). The original purpose of the facility was to store the spent nuclear fuel for approximately a 10-year period, until it was safe to transport to the Soviet Union. For his reason, the original storage capacity was 5040 spent nuclear assemblies. Later, the capacity of the wet interim storage was extended particularly by rearranging the stored fuel assemblies and replacement of the storage tanks. The current storage capacity is 14 112 spent fuel assemblies. Soon this capacity will not be sufficient for the spent nuclear fuel from all operating nuclear power plants in Slovakia.

As a result, the nuclear and decommissioning company (JAVYS, a. s.) is currently implementing the project “Completion of the construction of the storage capacity of spent nuclear fuel in the locality of Jaslovské Bohunice” – planned in two stages. The storage capacity will be increased by at least 10 100 spent fuel assemblies in the first stage and by at least 8 500 spent fuel assemblies in the second stage. The new storage capacities will use dry storage technology and are expected to be commissioned in 2022.

The costs for storage of the spent nuclear fuel from the operating nuclear power plants are reimbursed by the power plants themselves. After the commencement of decommissioning activities, they are reimbursed from the contributions accumulated in the NJF. At present, the costs for the storage of 5143 fuel assemblies from the nuclear power plant V1 are reimbursed from the NJF resources. Seismic enhancement of the ISFS as well as the new storage tanks increasing the capacity of the interim storage were also reimbursed from the sub-account g) intended for this purpose. Until the end of 2018, the sum of € 97.6 million was spent by the NJF for these activities.