Confinement shelter for the Chernobyl sarcophagus : dual French engineering for an exceptional project
24 March 2016 - Projects update and handover - Ukraine
NOVARKA, a 50/50 joint venture formed by VINCI Construction Grands Projets (leader) and Bouygues Travaux Publics, is currently building a new safe confi nement over the Unit 4 reactor at Chernobyl, which exploded on 26 April 1986.
This unparalleled project comprises the design and construction of a confi nement shelter in the form of an arch that will cover the current object shelter, or sarcophagus, built in 1986 just after the accident. Standing on two concrete beams, the metal arch will be assembled in an area to the west of the damaged reactor and slid into place above the existing object shelter.
Standing on two concrete beams, the arch has been assembled to the west of the damaged reactor and will be slid into position over the existing object shelter, built in 1986 just after the accident.
The purpose of the new arch, designed and built by NOVARKA, is to:
– contain radioactive materials;
– protect workers at the site;
– protect the existing object shelter against weather damage.
It will be fitted with equipment and facilities to allow work to begin on deconstruction of Unit 4 under the safest and most fl exible conditions possible, keeping human intervention to the strict minimum.
The video below will show you the cinematic of the project - to get more information, check the index in the "Know more" box :
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Overall project timeline (as of February 2016)
2011 Finalisation of the civil engineering work in the assembly area
2012-2015 Assembly of the arch
2015-2016 Installation of electro-mechanical equipment (systems)
End 2016 Sliding of the arch
End 2017 attach the membrane to completely seal the arch, commissioning tests and equipment handover.
Media contacts
Stéphanie Malek
Tel: +33 1 57 98 66 28
media.relations@vinci.com
An unprecedented project
The arch-shaped confi nement is made up of a 25,000 tonne (36,000 tonnes equipped) metal structure. With its 108-metre height, 162-metre length and 257-metre span, the outsized arch is large enough to enclose the Stade de France, the Statue of Liberty, or the footprint of the Eiff el Tower. It is as tall as a 30-storey building.
The confinement must withstand temperatures ranging from -43°C to +45°C, a class 3 (1,000,000 year) tornado, an earthquake reaching a maximum intensity of 6 on the Mercalli scale (10,000 year earthquake). Ukraine is a low seismic risk zone. The design earthquake epicentre is in Romania, 300 km away, and has a magnitude of about 7 on the Richter scale.
Safety of personnel, a constant priority
NOVARKA’s top priority is to protect the population and personnel. The site is monitored (radiation and atmospheric pollution) at all times throughout the project. Workers are also constantly monitored. A dedicated team of 60 duly qualifi ed radiation protection specialists is tasked with ensuring site safety.
Design and construction methods are governed by the «ALARA» (As Low As Reasonably Achievable) principle applying throughout the nuclear industry. During the planning and design phase, this consists in examining a range of solutions to a given problem and calculating the «committed dose budget» for each one(1). Unannounced evacuation drills are regularly held throughout the project.
All personnel working in the area are outfi tted with appropriate personal protective equipment (coveralls, masks, boots, helmets, gloves) and two dosimeters. The legal dosimeter records monthly doses received. The operational dosimeter monitors the actual radiation dose in real time and compares it with the predicted calculated dose. The recorded data is checked twice daily by NOVARKA radiation protection technicians at the site and analysed by the contracting authority’s laboratory.
If the budget is exceeded (which is in principle impossible, given the prevention procedures), personnel may be refused access to the work zone. Additional specifi c protocols include such procedures as systematic analysis of the data by a radioprotection specialist. For certain types of work, notably in areas near the object shelter (foundation beams, for example), personnel work behind concrete or lead screens. The radiation protection measures and rules applying at the site are the same for all workers - expatriate NOVARKA workers, Ukrainian NOVARKA workers and NOVARKA subcontractors alike.
At the arch assembly site, where the area has been cleaned up and doses are low, the procedure is less stringent. Workers keep their masks with them but wear them only in case of an alert.
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Arch span 257 metres
Arch height 108 metres
Covered length of the arch metres (nearly two football pitches) 162 metres
Metal frame (nearly 3 times the weight of the Eiffel Tower) 25,000 tonnes
Total weight of the equipped structure 36,000 tonnes
Life span of the confinement shelter: 100 years
Further information
On the web
NOVARKA Ukraine"