EJOT self-drilling screws make a contribution to highest safety of the Chernobyl reactor
On 26th April 1986, almost 26 years ago, the worst case scenario happened in the number 4 reactor of the Chernobyl nuclear power plant. Ever since then a provisional sarcophagus has been securing the reactor. But the porous construction leaks water and dust can escape. It has been predicted to hold up for 20 to 30 years. The current stabilising construction work will protect the rusty protective cover from crumbling until around 2023. The new protective cover  securely confines the remains for the next 100 years. It will be equipped with screws from EJOT.
In India, EJOT is a joint venture between EJOT Gmbh and Lakshmi Precision Screws.
New shield with EJOT self-drilling screwsThe new shield in the Chernobyl nuclear power plant is the largest movable structure ever built. In April the building work of the new sarcophagus began and the planned end date is summer 2015. The destroyed reactor will then be securely encased for at least 100 years. Construction directly over the old sarcophagus is not possible due to the high radiation on site. For that reason the shield is being built on nearby premises and will be pushed over the existing sarcophagus.
Quality and deliverableDuring the selection of possible suppliers EJOT was able to convince in two aspects. The company was able to answer comprehensive technical questions in detail and EJOT also guarantees complete quality service. This means that all production and process steps are continuously monitored, starting with an incoming goods inspection of the raw material up to final inspection – the identity check. Here it is very important for the South-Westphalian company to meet the claim of quality leadership. Standardised manufacturing processes as well as in-house testing according to the specifications of the EOTA (European Organisation for Technical Approvals) are guaranteed.
Project descriptionName Chernobyl New Safe Confinement (or: The Chernobyl arc).
Project• Construction of a new shield (sarcophagus) for the destroyed reactor block 4 of the Chernobyl nuclear power plant• Largest movable structure ever built.
Construction companiesEuropean Consortium Novarka was awarded the contract in September 2007.
Function of the shield• Secure encasement of the reactor block 4 for at least 100 years• Protection from corrosion and other aggressive environmental influences• Prevention of water penetration and release of radioactive dust• Enabling the dismantling of the unstable remaining structure• Enabling the recovery of the fuel rod remains
Design• Proven steel structure made of 16 arch shaped braced metal pipe constructs to minimise repair and maintenance work.• Installation of a crane for the disassembly of the old sarcophagus.• Attached gable walls enable pushing of the structure over the reactor.• A double-walled outer skin is attached to the structure in order to seal the inside from the outside and this way isolate it from weather exposure.• External cladding and internal cladding; space in-between around 13.8 m• Temperature and relative humidity can be regulated.
DimensionsWeight: 29.000 tonnes, span: 257 metre; length: 164 metre; height: 109 metreDesign sections/time planningThe shield will be built in two design sections. These sections are again divided into four steps. The first part of the shield will be built between April 2012 and October 2013. The second half will be built between November 2013 and June 2015.
EJOT products usedSUPER-SAPHIR self-drilling screw of the JT3 family
Function of the EJOT products• Fastening trapezoidal profiles on steel purlins• Fixing the inner and outer cladding• Fixing the intermediate profile (top hat section) to the trapezoidal profilen