Construction Chernobyl new safe confinement starts

Nuclear Monitor Issue: 
#749
4232
11/05/2012
WISE Amsterdam
Article

On April 26, Ukraine's President Viktor Yanukovych launched construction of the New Shelter Confinement that will be placed over the damaged Chernobyl nuclear power plant. The construction launch was timed to mark the 26th anniversary of the explosion and fire in Chernobyl Unit 4 that resulted in the world's worst nuclear power plant accident.

A few weeks earlier, the first batch of steel has arrived at the reactor site for the giant arched structure that will protect the ruined power plant and enable its dismantling. Last July enough funds for the Chernobyl Shelter Fund were collected (almost 1 billion dollars) and work was then expected to start in October 2011.

The 149 ton consignment received at the site will go towards the central segment of an arch some 108 metres high that will extend for 257 meters over the plant buildings. Supplied from Italy, the first batch arrived by rail; the second, which makes up some 1030 tons, will follow by sea and road. In total some 20,000 tons of steel will be required for the Chernobyl New Safe Confinement (NSC) project.

The structure 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. The structure is scheduled to be moved over the sarcophagus and confine the remains of the plant from the outside world for about 100 years. It is expected to be completed in 2015. It 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.

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 (EBRD).

In March 2004 the EBRD invited tenders for detailed design and construction of the New Safe Confinement: a freestanding arch to provide protection from weather and condensation and to minimise further corrosion for 100 years. It was then expected to be finished in 2010. In August 2007, the French consortium Novarka was announced as winner of the tender.

In July last year, the Ukrainian minister of foreign affairs announced that sufficient funds had been pledged to enable the start of construction of the NSC. Kostyantyn Grushchenko notified President Viktor Yanukovych of the outcome of a meeting of the international donors to the Chernobyl clean-up fund at the headquarters of the EBRD in London. Aside from the news on funding, Grushchenko noted that there were still a number of "issues requiring technical completion." But he said: "It is very important for us that already now, this year, we can start building the shelter, which will protect Kiev, Ukraine, the world from possible risks associated with the consequences of the Chernobyl disaster", he said.

According to a report from the German Press Agency (DPA), a spokesman from the Ukrainian Ministry of Foreign Affairs said that the country had received international pledges of US$941 million to build the steel-and-concrete structure.

The pledges will be used primarily to complete the New Safe Confinement. But the pledges will also help to complete the construction of a storage facility on the site for the used fuel from the three other Chernobyl units, which continued operating after the 1986 accident. The facility will provide dry storage for more than 20,000 used fuel assemblies on completion in 2014-5.

Sources: Nuclear Engineering International: Chernobyl – New safe century, April 2004 / Ria Novosti, 16 April 2006 / World Nuclear News, 9 August 2007, 13 July 2011 and 20 March 2012.

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