Progress in decommissioning of V1 NPP primary circuit contaminated components
The overall strategy for decommissioning of primary contaminated components, being in the scope of Slovak company VUJE, a.s., is their fragmentation in-situ or in established dry cutting workshops to the fragments with mass less than 1 ton which are suitable for further decontamination in order to maximize the amount of materials to be released to environment for further re-use. Moreover, the location of fragmentation activities into separate workshops or workplaces enables the application of additional measures (e.g. construction barriers, local ventilation systems, limited access of workers, measures for avoiding the potential leakages of radioactivity) to increase the safety level of fragmentation activities. Dismantling and fragmentation of following contaminated main primary circuit components of V1 NPP is currently under implementation:
- Steam Generators - (12 pieces) were extracted from the premises of hermetic area and manipulated to the Turbine Hall to the previously established temporary storage areas. In the meantime, the dry cutting workshop for SGs was constructed. After successful completion of the testing, the first SG fragmentation was completed, including the management of materials. Currently, the fragmentation of next SGs is in progress.
- Pressurizers together with Pressurizer Relief Tanks (1 per each unit) – after establishment of separate fragmentation workplaces (in-situ near the components), both components were fragmented by using wire saw cutting as well as thermal cutting methods. Currently, fragmentation of both Pressurisers as well as Relief Tanks is successfully completed.
- Primary piping – after tag-out from other primary circuit components, the primary pipping was removed (cuts were done by orbital saw) and fragmented by using a large band saw. Currently, the fragmentation of primary pipping on both units is completed.
- Main Circulation Pumps (12 pieces) and Main Isolation Valves (24 pieces) – two dry cutting workshops with wire saw and large band saw were established in the hermetic areas. The fragmentation of both components is now in progress and the goal is to achieve the complete fragmentation of 6 Main Circulation Pumps and 12 Main Isolation Valves in 2020.
Moreover, the dismantling and fragmentation of large extent of auxiliary systems and components related mainly to the main primary circuit contaminated components within the hermetic area is being continuously performed after completing the lock-out and tag-out of the relevant systems.
During implementation of contaminated components dismantling and fragmentation, the relevant measures and principles are continuously applied to keep the level of safety at the maximum applicable level focusing on the occupational health and safety (including fire protection), radiation protection as well as minimization of radioactive waste production.