Work to assemble the giant arched structure that will protect the ruined Chernobyl unit 4 and enable its dismantling has officially begun on the 26th anniversary of the accident.
|President Viktor Yanukovych launches the assembly of the Chernobyl New Safe Confinement
After laying flowers at the memorial near the plant's north gate that commemorates the work of those that took early action during the accident, Ukrainian President Viktor Yanukovych took part in a ceremony to launch the assembly of the New Safe Confinement (NSC) structure. This arched structure - some 108 metres high, 257 metres wide and 150 metres long - will be assembled on concrete rails and slid into place over the broken buildings of Chernobyl 4, which was destroyed by the steam and hydrogen explosions that followed a power excursion in April 1986. Some 20,000 tonnes of steel will be used in the structure's construction, the first batch of which was delivered to site last month.
The hermetically sealed NSC will allow engineers to remotely dismantle the hastily constructed 'sarcophagus' that has shielded the remains of the reactor from the weather since the weeks after the accident. The stability of the sarcophagus has developed into one of the major risk factors at the site, and its potential collapse threatens to liberate more radioactive materials. A project to shore up the structure was completed in mid-2008 but the NSC would reduce the consequences of a collapse while also allowing the sarcophagus to be taken apart under controlled conditions.
Other objectives for the structure are to generally reduce emissions from the buildings for a design-life of 100 years while at the same time stopping the ingress of water, which increases the risk that nuclear fuels scattered inside the building could potentially see sustained fission reactions. The huge building is meant to enable the eventual removal of materials containing nuclear fuel and accommodate their characterisation, compaction and packing for disposal. This task represents the most important step in eliminating nuclear hazard at the site - and the real start of decommissioning. The NSC will facilitate remote handling of these dangerous materials, using as few personnel as possible.
Yanukovych told those gathered at the site, "We are witnesses to a historic event in the transformation of the Object Shelter into an ecologically safe system: the construction of the arch of the Chernobyl nuclear power plant." He added, "This project's successful implementation will ensure that the surrounding area becomes environmentally safe and that there are no radiation leaks into the atmosphere."
The environmental restoration work at Chernobyl is funded by 29 donor countries to the Chernobyl Shelter Fund, set up in 1997, which is administered by the European Bank for Reconstruction and Development. The necessary funds for the €470 million ($621 million) project were secured in July 2011.
The NSC structure is being built by the French-led Novarka consortium, which includes Bouygyes and Vinci, as well as German and Ukrainian firms. Under the contract, it is planned to be in place by October 2015.
Researched and written
by World Nuclear News