Wednesday, November 16, 2016

Enormous containment arch finally moving into place over exploded Chernobyl reactor

November 16, 2016 Over the next five days, engineers at Chernobyl, the Ukrainian site of the world’s worst nuclear disaster, will be moving an enormous roof over the still irradiated remains of the plant’s No 4 reactor. Hopes are high that the new superstructure can contain radiation while Ukraine works to deal with the nuclear waste within the exploded reactor. Bellona’s executive director and nuclear physicist Nils Bøhmer, however, said the new roof will not entirely remove radiation dangers from the area. Chernobyl’s reactor No 4 exploded on April 26, 1986, and over the ensuing 10 days, its nuclear fuel continued to burn, issuing clouds of poisonous radiation and contaminating as much as three quarters of the European continent, hitting northern Ukraine, Russia and Belarus, especially hard. Sweden was the first country to report irregular radiation readings. The Chernobyl plant was the suspected culprit, but Soviet officials remained mum.
Construction of the "sarcophagus" at the Chernobyl Nuclear Power Plant, Ukraine, following the explosion on April 26, 1986. UPI/INS
In the days following, 116,000 people were evacuated while some 600,000 liquidators, comprised of police, fire fighters, military and engineers, operated in chaotic and dangerous conditions, often without protective gear, to implement a containment structure of cement and steel to squelch emissions of radiation. The ad-hoc structure trapped 200 tons of uranium, but many liquidators feared at the time that the cement barrier would eventually give up. In 2005 it did.
This week, the New Safe Confinement, a €1.5 billion ($1.6 billion), 36,000 ton steel structure, will slide into place with the goal of trapping that radiation for the next 100 years – by which point it is hope engineers will contain it for good. Financed by donations of more than 40 countries coordinated by the European Bank of Reconstruction and Development, the New Safe Confinement is the largest movable land-based structure on earth, and will fully enclose the remains of Chernobyl’s No 4 reactor.
A view of the New Safe Confinement structure. (Photo: Nils Bøhmer)  
The arch structure is the largest moveable land-based structure ever built, with a span of 257 meters, a length of 162 meters, and a height of 108 meters. That’s big enough to house London’s St. Paul’s cathedral or Paris’s Notre Dame. The London-based EBRD calls it “one of the most ambitious projects in the history of engineering”. The New Safe Confinement was constructed in a clean area near No 4 reactor and will over the next week slide a little more than 327 meters to seal off the unit, World Nuclear News reported. It’s hoped to make the site safe to allow for eventual dismantling of the crumbling concrete shelter, called the sarcophagus, currently covering the remains of the reactor. It will also facilitate management of the waste within the structure, the EBRD said.