НБКProject "New Safe Confinement Construction"

Employer: Chernobyl nuclear power plant (ChNPP)

Engineer: Project Management Unit (PMU) – Bechtel (USA) – Bettelle Memorial (USA) – ChNPP

Contractor (Designing – Procurement - Construction): Joint venture NOVARKA, France (VINCI Construction Grands Projets - 50% / Bouygues Travaux Publics - 50%)

Funding: Chernobyl Shelter Fund (CSF)

CSF Administrator – EBRD

Contract Price: 1 424 mln €

Contract signing date – August 10, 2007.

Major Subcontractors:

CIMOLAI – Italy: Working design and steel constructions manufacturing

PaR – USA: Design and Main cranes system manufacturing

OKYANUS – Turkey: design, supply and installation of cladding

NSC in figures:

Span of Arch

257m

Length

162m

Height

108m

Lifetime

100 years

Temperature range

-30°C to +50°C

Seismic zone

2 (9 points on the Richter scale)

Foundations and platform of assembling area

81 000м3 of reinforced concrete

Steel piles - length 25 m and diameter 1 m

400 pieces

Concrete piles - length 19 meters and 1 m diameter (permanent foundations)

400 pieses

Arch construction:

- Main elements ( pipes with diameter >800 mm)

- auxiliary components (joint connections)

- fixations (bolts M30)

 

5700 pieses

4000 pieses

650000 pieses

Steel constructions

24 860 tons

Temporary constructions

5400 tons

Cladding:

- external (multi layers)

- internal

 

86 000m2

78 000m2

Workforce at the site (in average)

2 shifts consisting of 600 persons

 

About the Project in details

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.

Construction progress:

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 Chernobyl 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

Select the another date

Within the NSC Project at the construction site the following works are being performed:
- Assembling of basic structures of the arch
- Assembling of hanger supports of crane beams
- Assembling of a container of jacking system
- Assembling of binding rafters of inner lining
- Assembling of Floline 70 steel flooring packs and omega profile
- Profiling of Kalzip panels
- Preparatory works for engineering building were performed

Assembly of the Arch metal structures (for 2nd lifting)
According to the design - 4,097 tons
1123,71 tons (27,4%) performed

Installation of the Arch roof’s outer cladding:
According to the design, surface area of outer cladding (Stage 1С) - 7,853.9 m2;
Surface area of cladding sections 2, 5 (Stage 2) - 6,098.3 m2;
Surface area of roof cladding before 2nd lifting - 13,952.2
м2.
Overall progress in the Arch outer cladding installation before 2nd lifting – 40,4%

Select the another date

Within the NSC Project at the construction site the following works are being performed:
- Assembling of basic structures of the arch
- Assembling of hanger supports of crane beams
- Assembling of upper platforms of hoisting towers
- Assembling of a container of jacking system
- Assembling of binding rafters of the cladding
- Assembling of binding rafters of inner lining
- Works on assembling of Floline 70 steel flooring packs were performed
- Profiling of Kalzip panels
- Preparatory works for engineering building were performed

Assembly of the Arch metal structures (for 2nd lifting)
According to the design - 4,097 tons
831,32 tons (20,3%) performed

Installation of the Arch roof’s outer cladding:
According to the design, surface area of outer cladding (Stage 1С) - 7,853.9 m2;
Surface area of cladding sections 2, 5 (Stage 2) - 6,098.3 m2;
Surface area of roof cladding before 2nd lifting - 13,952.2
м2.
Overall progress in the Arch outer cladding installation before 2nd lifting – 37,1%

Select the another date

Within the NSC Project at the construction site the following works are being performed:
- Assembling of basic structures of the arch
- Assembling of hanger supports of crane beams
- Assembling of upper platforms of hoisting towers
- Assembling of a container of jacking system
- Assembling of binding rafters of the cladding
- Assembling of binding rafters of inner lining
- Works on assembling of Floline 70 steel flooring packs were performed
- Profiling of Kalzip panels
- Preparatory works for engineering building were performed

Assembly of the Arch metal structures (for 2nd lifting)
According to the design - 4,097 tons
645.3 tons (15.7%) performed

Installation of the Arch roof’s outer cladding:
According to the design, surface area of outer cladding (Stage 1С) - 7,853.9 m2;
Surface area of cladding sections 2, 5 (Stage 2) - 6,098.3 m2;
Surface area of roof cladding before 2nd lifting - 13,952.2
м2.
Overall progress in the Arch outer cladding installation before 2nd lifting – 36.2%

Select the another date

 

Within the NSC Project at the construction site the following works are being performed:
- installation of outer cladding purlines; 
- installation of inner cladding purlines;
- erection of lifting towers’ sections;
- assembly of Floline 70 steel decking laminates;
- preparatory works before arrangement of a fire pump house;
- lifting of a jacking system container for a tower.

Assembly of the Arch metal structures (for 2nd lifting)
According to the design - 4,097 tons
393.98 tons (9.6%) performed

Installation of the Arch roof’s outer cladding:
According to the design, surface area of outer cladding (Stage 1С) - 7,853.9 m2;
Surface area of cladding sections 2, 5 (Stage 2) - 6,098.3 m2;
Surface area of roof cladding before 2nd lifting - 13,952.2 м2.
Overall progress in the Arch outer cladding installation before 2nd lifting – 35.6%

 

Select the another date

Within the NSC Project at the construction site the following works are being performed:
- preparation for assembly of lifting towers
- assembly of the lifting towers
- dismantling of the lifting towers’ sections
- removal of snow and ice from the site and crane runways
- installation of outer cladding purlines
- assembly of Floline 70 steel decking laminates

Assembly of the Arch metal structures (for 2nd lifting)
According to the design - 4,097 tons, 123,98 tons (3%) performed

Assembly of the Arch section outer cladding after 1st lifting
According to the design – 7,847.07m2 area
60.47% performed

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Within the framework of the NSC project at the construction site the following activities were implemented:
-        preparation of lifting towers for assembling;
-        assembling of infill elements of main structures;
-        clearance of site and crane rails from snow and ice;
-        Installation of arch metal constructions up to 2-st lifting - according to the design - 4097 tons, installed 103,98 tons (2,54%)

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June 11, 2001 – establishment of SSE Chernobyl NPP

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