Extent of the planned activities

The principal aim of the B6.7 project is to obtain a Final Statement of the Ministry of Environment SR that will allow, together with the licence for the 2nd stage of V1 NPP decommissioning, for carrying out all activities planned for the 2nd stage of V1 NPP decommissioning in order to successfully complete the V1 NPP decommissioning process. Strong emphasis is at the same time laid at minimizing the necessity of carrying out further assessment activities that might occur during the 2nd stage of the decommissioning process. Basic documents that define the individual activities to be carried out in the 2nd stage of decommissioning are:

• B6.3-D5 "Decommissioning concept for the period after the licensed decommissioning stage"
• Strategy of Bohunice V1 NPP Decommissioning.

Based on the document B6.3-D5 "Decommissioning concept for the period after the licensed decommissioning stage", the decommissioning activity, after the completion of the 1st stage of decommissioning, focuses on objects of the main production unit, auxiliary service building and the remaining auxiliary civil structures  that were not, or only partially decommissioned in the 1st decommissioning stage, and the final treatment of the site.
The planned final state of V1 NPP decommissioning shall allow for further use of the site.

Major groups of activities in the period after the completion of the 1st stage of V1 NPP decommissioning are the following:

• Preparation and dismantling of reactors
• Preparation and dismantling of primary circuit equipment
• Dismantling of other equipment in the controlled area. 
• Decontamination and radiation control of civil part of operated civil buildings.
• Demolition of originally operated civil buildings up to the foundation plate.
• Dismantling in non-operated objects.
• Demolition of non-operated civil buildings up to the foundation plate.
• Final treatment of the site.

The mentioned activities will be managed and supported by activities such as management, technical support, operation of auxiliary systems, radiation protection, maintenance, monitoring, security etc.
The most significant activities after the completion of the 1st decommissioning stage will be the dismantling of reactors and of the primary circuit equipment. Other activities, such as dismantling of other equipment in and outside the controlled area, decontamination of equipment and building surfaces, its radiation control and demolition and treatment of the site, are standard activities in respect to which there is sufficient experience from other decommissioning projects, including the national ones.

In view of the adopted alternative of immediate decommissioning, the dismantling of the V1 NPP reactors will constitute the most challenging technical part of works. On the basis of contemporary experience with reactor dismantling in the world and the dismantling approach so far evaluated in decommissioning conceptual plans for V1 NPP and other NPPs in SR with reactors of the VVER 440 type, the following basic dismantling concepts can be considered:

• Fragmentation of inner components of the reactor and the reactor pressure vessel in situ.
• Dismantling, storage and disposal of the reactor pressure vessel as a whole.
• Fragmentation of the inner components of the reactor in situ, dismantling and storage of the RPV as a whole.

In the area of radioactive waste management, execution of standard activities is expected, such as processing, treatment and storage of low and medium level waste, transport and storage of FCC in the NRR Mochovce, handling with VLLW, release of materials into the environment and management of other and dangerous waste. It is assumed that in the period after the completion of the 1st decommissioning stage, an Interim Radioactive Waste Storage be operational, giving the possibility to store, over a limited period, the RAW that cannot be stored in NRR Mochovce.
The individual activities resulting from the main work complexes mentioned above are defined into projects in the document "V1 NPP Decommissioning Strategy". Summing up, the activities of the 2nd decommissioning stage comprise the dismantling of the primary circuit and of the remaining contaminated and not contaminated systems as well as decontamination of any contaminated equipment and civil buildings, demolition, final treatment of the site and release of the site from the scope of the nuclear legislation and will be implemented in form of projects, e.g.:

• D2.1 Decontamination of storage basins and other contaminated vessels at V1 NPP
• D4.1 Modification of the plant and installation of new equipment
• D4.2 Dismantling of reactor coolant system large components
• D4.4B Dismantling of systems in V1 NPP controlled area - part 1
• D4.4C Dismantling of systems in V1 NPP controlled area - part 2
• D4.5 Reactor and Auxiliary Buildings Decontamination
• D4.6 Building Demolition & Backfilling
• D6.1 Site Restoration
• D6.2 Final Survey & Site Release
• C14 Disposal of remote handled waste from mogilnik
• C12.2 Laboratory equipment necessary for the process of V1 NPP decommissioning - 2nd stage.