Since 1992 an active work on Shelter Object transformation into an ecologically safe system, including those performed under international programs, has been implemented. The main conclusion of this long-term research is that a considerable reduction of Shelter Object’s hazard can be achieved by constructing a new protection structure over the Shelter – that is a New Safe Confinement (NSC).

The necessity of creating the NSC is set forth in the following documents:
- Law of Ukraine “On the general principles of the further Chernobyl NPP operation and decommissioning, and transformation of the destroyed 4th Unit of this NPP into an ecologically safe system”;- Shelter Object Transformation Strategy approved by a Decision of a Government Commission on the Issues of Comprehensive Chernobyl NPP Problem-Solving;
- Shelter Implementation Plan adopted in June 1997 at the G7 meeting.

In the Law of Ukraine “On the general principles of the further Chernobyl NPP operation and decommissioning, and transformation of the destroyed 4th Unit of this NPP into an ecologically safe system” are laid down the basic requirements to the Confinement:
“The Confinement is a protection facility comprising a set of processing equipment for removal of materials containing nuclear fuel from the destroyed Chernobyl NPP 4th Unit, radioactive waste management and other systems designed for transforming this Power Unit into an ecologically safe system and ensuring the safety of personnel, public and environment”.

 

In accordance with the Conceptual Design the NSC includes:
- the main facility comprising the Arch structure, chord of which is 257.44 m towards North-South, height – 108.3 m and length - 150 m;
- foundations, western and eastern end walls, required supporting and auxiliary systems;
- processing building including sections for decontamination, fragmentation and packing, sanitary locks, workshop and other process premises;
- auxiliary structures.

To assure nuclear, radiation and general industrial safety of the NSC facility and its efficient operation involving a minimum number of operating personnel it is envisaged to establish an Integrated NSC Management System.
It will include such systems as:
- Radiation safety monitoring system;
- Seismic monitoring system;
- Monitoring system of building structures state;
- Operation support systems: ventilation, water supply, sewerage (including liquid radioactive waste management) and power-supply systems;
- Process systems for management of radioactive waste and fuel-containing materials.
In addition, fire safety and physical protection systems, communication and TV networks will be installed. Crane equipment will be erected to ensure dismantling of unstable structures.

Main NSC functions:
1. Limit the radiation impact on public, personnel and environment within the established boundaries, both during normal Shelter Object operation and in case of normal-operation disturbances, emergencies and accidents, including accidents occurring during dismantling of unstable structures and future management of fuel-containing materials (FCM) and radioactive waste (RAW).
2. Limit the spread of ionizing radiation and radioactive substances contained within the Shelter Object.
3. Technology process support – i.e. creating conditions for dismantling of unstable structures, future FCM and RAW removal, accumulated water removal, ensuring that measures on monitoring and maintenance of the Shelter Object and its Industrial Site are implemented.
4. Monitor all the Shelter state parameters and manage technology processes.
5. Physical protection – i.e. prevent unauthorized access to FCM and RAW, and ensure functioning of the IAEA safeguards system.

The NSC construction will enable the following to be achieved:
•          increased level of radiation safety – the NSC cladding safety would limit radiation impact on public, personnel and environment for 100 years of operation;
•          reduced probability of accidental collapse due to dismantling of unstable structures;
•          reduced consequences of accidental collapse owning to enclosing and bearing structures, and monitoring systems inside the NSC;
•          improved Shelter Object nuclear safety by preventing atmospheric moisture from getting onto FCM accumulations, that considerably reduces the risk of occurring a self-sustained chain reaction;
•          ensured implementation of the Shelter transformation strategy owning to durability of the NSC structures, and possibility of dismantling of unstable structures of the existing Shelter Object and removal of fuel-containing materials.

The Safe Confinement as a multifunctional facility with the service life of 100 years in future will enable to remove fuel-containing materials and their conditioning for further safe storage.

The NSC Conceptual Design ordered by ChNPP was developed by a Consortium of Bechtel и Battelle (USA), and EDF (France) involving the Ukrainian “KSK” Consortium (Scientific and Research Institute for Civil Structures (NIISK), Kyiv Institute “EnergoProekt” (KIEP), and Interdisciplinary Scientific and Technical Center “Shelter” (now an Institute for NPP Safety Problems)).

The Conceptual Design was discussed at public hearings held in March 2004 in Slavutych, as well as within Ukrainian scientific circles, and it passed a comprehensive state expert examination. Under the results of these discussions the Cabinet of Ministers of Ukraine approved this Design as a basis for further design work by its Order №443-r dated July 5, 2004.

The Conceptual Design justifies the possibilities to implement the proposed engineering solutions, assesses the ecological NSC efficiency as compared to the existing level of Shelter Object impact on environment, and evaluates terms of construction and financial expenditure required for the NSC creation.

On August 10, 2007, after an open international two-stage tendering, the SSE “Chernobyl NPP” and International Consortium NOVARKA comprised of two French companies “VINCI Construction Grands Projets” and “Bouygues Travaux Publics” concluded a contract for designing, construction and commissioning of Commissioning Stage 1 (CS-1) of the New Safe Confinement.

NSC Progress

At the first stage started in 2008 and actually completed in 2011, the preparatory activities were performed provided for safe and efficient construction of NSC. Particularly, a large scope of works were performed relating to clearing and planning of the area, arrangement of foundation pits for construction of the foundations for assembly, transport and service areas of NSC, and mounting site for assembly of the Arch’s structures in major units.

Complexity of performing these activities was that man-made soils in the places of excavation works had the significant radioactive contamination and belonged to radioactive waste (RAW), including high-level ones.

During the first stage, the following temporary facilities were commissioned: 3 concrete plants, new high-voltage line for concrete plants, premise for construction laboratory, office premises, repair shops, warehouses, medical units, premises for eating, etc.

During the second stage, the activities on design and construction of NSC are being carried out. The stage of basic design is completed. The project was divided into several licensing packages, gradual development of which enabled to perform works almost continuously relating to the packages which passed the expert review and issued for production. Upon expert review, the final licensing package was approved in April 2013, and the State Nuclear Regulatory Inspectorate of Ukraine has issued to the operating organization a separate permit for its implementation.

The history of the Arch assembly has started on February 13, 2012, when the first batches of basic metal structures were delivered to SSE ChNPP site.

The first lifting was carried out on November 24, 2012, resulting in successful lifting of over 5,300 tons of metal structures. The height of east side of the Arch following the first jacking was 53 metres. The second lifting was accomplished on June 13, 2013. The operation was completed successfully. At that moment, the structure weight was 9,100 tons.

The third lifting of the Arch differed from previous operations, thus it included several stages. The first stage is the Arch jacking to the height a bit more than 110 metres. This operation was carried out on September 14-16, 2013. Following this, the side segments of the Arch were assembled, as well as the supports. At this, the Arch was in suspension.

Simultaneously, the sliding rails were mounted and other secondary structures on assembly area foundations as well. On October 11, 2013, the load was transferred from the Arch to the foundation.

During April 1-3, 2014, the operation regarding displacement of east side of the New Safe Confinement’s Arch to the holding area was performed successfully.

The first lifting of west side of the Arch was carried out on April 26-27, 2014. The structure was lifted to 23 metres height and fixed using a lockout system in suspension for assembling the side segments. On May 19, 2014, the west side was taken down and fixed using the holding devices transferring 100% load to the foundations.

The second lifting of west side of the Arch was performed on August 2-4, 2014. The weight of the structures was 8,351.73 tons. The structure was lifted to 32.2 metres height and fixed using a lockout system in suspension for assembling the side segments. The total height of the Arch’s west side is 85.49 m.

On August 26, 2014, following the second jacking, the west side of the Arch was taken down and fixed on holding devices transferring 100% load to the foundations.

The third lifting of west side of the Arch was successfully completed on November 12, 2014 (the Arch was put on supporting units and fixed on holding device, and the load was transferred to the foundations).

On November 26, 2014, the first stage of return sliding of the Arch was accomplished. The east side of the Arch was moved 25 metres toward west side.

On July 24, 2015, joint assembly of west and east sides of the Arch was performed.
On October 4, 2015, the activities on joining east and west sides of the Arch were completed (bolt joints are compressed for 100%).

On November 28, 2015, the jacking of the west bridge of the main crane system (MCS) was completed. On December 7, 2015, the load was transferred from the lifting system to the crane beams.

On December 16, 2015, the west bridge of MCS was moved to the holding area.

2016:
- Metal structures (MS) of the Arch are being assembled;
- Metal structures of the Arch are being delivered to the site;
- Components of east bridge of the main crane system are being delivered. The Contractor is performing structural reassembly of east bridge;
- Activities relating to arrangement of external and internal space of NSC are under implementation: outside underground engineering lines (construction unit: electric power supply, water supply and sewerage, cabling).

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