In accordance with the Project Implementation Strategy, the NSC will be constructed in three stages.
STAGE 1. Preparatory works
At the first stage preparatory works were performed which ensured a safe and efficient construction of the NSC.
The preparatory works in turn were performed in three phases:
Preparatory Works Phase 1:
- Removal of Pioneer Wall Berm
In 1986 the Pioneer Wall was used as an erection platform for a DEMAG assembly crane which erected southern metal structures of the constructed Shelter. The necessity of Pioneer Wall Berm’s disassembling was dictated by location of the NSC foundation in this area. Based upon the Berm’s design the different technologies and engineering tools for demolition of concrete and reinforced concrete cast-in-situ structures, dismantling of built-up structures, as well as removal of backfilling materials of a complex structure (crushed stone, sand, soil, concrete and metal fragments) were used for its removal.
The activities were performed under radiation hazardous conditions directly near the Shelter Object. Moreover, the Berm’s materials themselves were radioactively contaminated to a different extent.
This required the removal and implementation of a set of measures on radiation protection of the personnel, engaged in performing the activities, and environment. Over 23.000 m3 of process materials and solid radioactive waste were removed during the work. This work was performed by “UkrTransBud” Corporation and successfully completed in April 2008.
Photo: Removal of Pioneer Wall Berm
- Area Clearance and Leveling, Excavation Activities for Construction of the NSC Foundations and Erection Area Before starting the main activities on the NSC construction a large scope of work was performed that envisaged cleaning-up and leveling of the area, preparation of trenches for constructing the foundations of the NSC erection, transport and service areas, as well as an erection area for pre-assembling the Arch structures.
The difficulty of performing these activities lied in the fact that man-induced soils possessed a considerable radioactive contamination and were referred to radioactive waste, including the high-level one. During the excavation activities a process scheme for RAW safe management was implemented. It envisaged step-by-step operation monitoring, RAW sorting by category and transportation to a temporary storage site or a final disposal facility.
The activities resulted in removal of over 32.000 m3 of process materials and solid RAW, 4 machinery units (cranes, tractor, excavation machines) buried under a layer of soil during the Shelter Object construction in 1986, as well as high-level waste discovered in the course of activities.
The clearance of the area for constructing the NSC foundations was performed in 2008-2010 by the SE “UTEM-Engineering” with the involvement of Ukrainian subcontractors.
Photo: Excavation activities for constructing the NSC foundations
Phase 2 of preparatory works – Preparation of infrastructure for NSC construction
For the purpose of timely and cost-effective implementation of works, in parallel with developing the NSC design, NOVARKA developed a working project and prepared facilities required for construction of NSC, its foundations, and for the mobilization on site. These facilities included:
- Temporary buildings and facilities for personnel (administrative, utility etc.);
- Works on improvement of roads to deliver materials and tools;
- Training facilities (training equipment etc.);
- Preparation of the site for NSC construction and installation works;
- Preparation of sites for storing/keeping of tools and materials for NSC.
Temporary facilities were commissioned, particularly, two concrete plants in the area of ISF-2 were brought back to operation, the third concrete plant was commissioned, a new overhead transmission line VL-6 kV for concrete plants was laid and put into operation, as well as premises such as the construction laboratory, offices, repair shops and first aid room an the former “Prypiat” garage area. Engineering research was conducted at SO industrial site.
Phase 3 of preparatory works – Construction of a new ventilation stack (NVS)
Since the NSC conceptual design contained a justified proposal to dismantle the ventilation stack of the 2nd generation of ChNPP, design documentation was developed and a new ventilation stack (NVS) of the 2nd generation of ChNPP was constructed (for consumer needs of Unit 3, liquid and solid waste storage facilities, and Shelter object, with simultaneous partial reconstruction of existing ventilation systems and radiation monitoring system). NVS was commissioned prior to dismantling of the existing ChNPP 2nd generation ventilation stack (VS-2).
Construction of the new ventilation stack of ChNPP 2nd generation was carried out by Ukryttia Consortium led by Atomstroyexport (Russia) and Ukrenergomontazh (Ukraine).
Photo: New Ventilation Stack erected near VS-2
STAGE 2. Design, Manufacturing, Construction and Commissioning of NSC
At the second stage of NSC project implementation, activities are being carried out on NSC design and construction, as well as the whole package of comprehensive testing and its commissioning.
Within the mentioned above stages there are two NSC commissioning stages:
The 1st commissioning stage (CS-1) is “Protective building with process-related life-support systems and necessary infrastructure.”
Joint venture NOVARKA is carrying out activities on NSC CS-1 design and construction. CS-1 scope of works includes:
1. Design and construction of temporary NSC foundations, the Arch structure together with cladding and Main Cranes System (MCS).
2. Design of the general internal arrangement of the NSC, hard insulating coating of areas inside the NSC, and sites etc.
3. Design, manufacturing, construction (installation) and commissioning of:
a. NSC process-related life-support and monitoring systems;
b. Outdoor engineering utility systems for connecting NSC life-support systems to the ChNPP systems.
4. Dismantling of the existing VS-2 prior to the Arch sliding into the design position.
The history of Arch mounting started on February 13, 2012, when the first batches of major metal structures were delivered to SSE ChNPP site.
NSC Arch was assembled in two separate parts - the eastern and the western parts, which were assembled turn and turn about and then they were connected in a single whole. To assembly the parts unique technologies were used stipulating lifting of the assembled structures up to the design height using a sophisticated jacking system. During 2012 - 2016 more than 30 thousand tons of Arch metal structures were installed and 6 liftings were carried out.
In parallel with the main building installation work installation of external and internal cladding, installation of ventilation systems and the main crane system equipment, necessary for the Shelter unstable structures dismantling were implemented.
To ensure radiation safety of the workers, Arch installation was carried out at a distance from the Shelter object at the specially constructed site. Within the period from November 14 to November 27, 2016, Arch structure was moved to 327.5 meters from the installation site and installed in the design position above the Shelter object.
At the moment construction of a technological building and auxiliary facilities is under way as well as works to arrange the NSC external and internal space.
Photo: Arch as of December 2017
Commissioning Stage 2 (CS-2) – “Infrastructure for Dismantling of Shelter Object Unstable Structures”
The CS-2 work scope will include:
1. Designing (development of a Detailed Design) for dismantling of SO unstable structures, including:
- design solutions for the "early" and "deferred" dismantling of SO unstable structures, in particular those which are located outside the area of NSC's main crane system (MCS) operation;
- designing of equipment, including remotely controlled, necessary for dismantling;
- designing of equipment and systems for primary handling of dismantled contaminated SO structures and associated RAW, their loading and transportation for transfer to the existing or creating ChNPP Radioactive Waste Management infrastructure;
- designing of the technological transport complex and facilities to provide personnel access and equipment delivery to the work site; mobile safety systems (sanitary locks, shielded cabins, other protection and shielding systems);
- designing of NSC's life support and monitoring systems extension as well as (if necessary) the relevant constructions, facilities, sites for their deployment to ensure dismantling process and subsequent NSC operation.
2. Procurement, installation and commissioning of process equipment and systems for dismantling unstable structures and their subsequent handling, and performing the necessary construction and installation work to expand NSC technological systems
Based on the decision to split SC-2 designing into two stages the first work stage "Conceptual investigation" was completed within the period 2012 - 2014. Technical solution "On early dismantling option selection to develop working design for SC-2 NSC "Infrastructure for SO unstable structures dismantling" was developed, approved and agreed by SNRIU based on its results.
Unfortunately, further designing of SC-2 was stopped due to the EBRD's decision to suspend funding for this task from the Chоrnobyl Shelter Fund (CSF).
SSE ChNPP is currently preparing materials for approval of an investment project for designing, implementation and commissioning of NSC SC-2 and dismantling of SO unstable structures by effective in Ukraine mechanism for State investment projects selection.
STAGE 3 – Early Dismantling
At the third stage, after commissioning of the CS-2 and Processing Building as a part of the integrated RAW management system at the ChNPP site, the early dismantling of the Shelter Object unstable structures can be started to the extent specified at a relevant detailed-design stage. Early dismantling activities and management of dismantled structures and associated RAW will be performed using process lines located within the Processing
Project "New Safe Confinement Construction"
