Tuesday marks the 25th anniversary of the fire and core meltdown at Chernobyl’s nuclear reactor four. Even now, the site requires tremendous care so that the remaining nuclear material does not escape.
Within a few months of the accident, officials put a concrete enclosure called the “sarcophagus” over the reactor, but the structure has been showing signs of wear ever since. It’s cracked; it lets the elements in and some radioactivity out. The yellow metal support structure visible in this photo was added to stabilize the sarcophagus, a process that was completed three years ago to prevent it from collapsing. Now, engineers financed by the European Bank for Reconstruction and Redevelopment, with contributions from the European Commission and countries including the United States, are working on two major remaining tasks (about $1.8 billion has been raised so far). Led by the consortium Novarka, they’re building new storage facilities for the spent nuclear fuel from other reactors on the site. And Novarka is undertaking one of the most complex construction projects ever, to create a seal that will go over the cracked sarcophagus. On an adjacent site, workers are building the foundations for a 100-meter-high steel structure that will be slid into place to seal it off until the reactor itself can be dismantled, in about 100 years.
The reinforced-concrete foundation for this structure, called the New Safe Confinement, is visible in the foreground of this photo. The gravel trench on the right is part of the track that will be used to slide the tremendous structure over the sarcophagus.