Chornobyl NPP Advances Phase 2 of Decommissioning

The decommissioning of the Chornobyl Nuclear Power Plant (ChNPP) is currently in the second of four phases, with the primary task being the final shutdown and decommissioning preparation of Reactors 1, 2, and 3.

To date, ChNPP staff are advancing on-site preparation work within the protected area of the first-stage units. Among these, site preparation for Unit 2 is 94% complete, while Unit 1 stands at 44%. Related work includes dismantling systems and components within the protected area, removing thermal insulation and combustible materials, stripping electrical, signal, and control cables, sealing wall penetrations, mounting holes, and process openings at the boundary between the protected and controlled areas, and installing fire-resistant panels and fire barriers on wall openings and ventilation ducts within the protected area.

According to the Work Execution Plan (WEP), all of the above work must be completed by December 2028. Maksym Protsenko, Head of the Engineering Center at ChNPP, stated that the plant has decided to incorporate these tasks into routine operational management, to be carried out by its own personnel in accordance with the plans developed by the Engineering Center.

Currently, the work plan for Unit 3 is also being developed, with actual construction expected to commence in 2027. After the plant staff complete the measures implemented on their own, contractors will continue the final decommissioning and containment project for the reactor facilities under the revised Final Decommissioning and Containment (FDC) project. This project is divided into two stages: first, the refurbishment of the main buildings of Units 1 and 2, and second, the refurbishment of the main building of Unit 3.

The refurbishment work includes lowering the ceiling height of the central hall by approximately 12 to 16 meters. To this end, the existing metal ceiling structures will be dismantled and new roofing will be installed. The removal of handling machinery and lifting equipment is also planned.

The work for the final decommissioning and containment phase of the reactor units is carried out under a separate license issued by the State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) on March 31, 2015. This phase focuses on implementing measures to ensure safety and create conditions for the long-term controlled storage of the reactor units, including dismantling systems and equipment components outside the reactors that do not affect safety and will no longer be used in subsequent decommissioning stages, strengthening barriers against the release of radioactive substances into the environment, reliably sealing hard-to-dismantle facility components, creating conditions for the temporary controlled storage of remaining radioactive materials on site, and collecting and processing radioactive waste (RAW) generated during the work before transferring it to specialized agencies for subsequent management.

Phase 1 of the ChNPP decommissioning was completed in 2015. This phase primarily involved unit shutdown and pre-decommissioning preparation, with the final key task being the removal of nuclear fuel and its transfer to spent fuel storage facilities for long-term storage.

According to the ChNPP decommissioning strategy, Phases 3 and 4 will respectively be the safe storage period and the dismantling period of the reactor units. The safe storage phase is planned to begin in 2034, provided that it has been confirmed that radioactive materials can be safely stored long-term within the limits and timeframes specified by the decommissioning project. The main tasks of this phase include operating the systems and components required to maintain the safe storage of remaining radioactive materials within the sealing facilities, and periodically inspecting the condition of these facilities.

In the subsequent dismantling phase, systems and components controlled as sources of ionizing radiation will be dismantled, removed, and transferred to radioactive waste storage facilities. Protsenko noted that this decommissioning approach complies with Ukrainian national regulations and international standards. Meanwhile, throughout the decommissioning of Units 1, 2, and 3, dismantling work on equipment outside the reactor buildings is also progressing in parallel.