Sustainable Energy

After 25 Years, Sealing Off Chernobyl

Dealing with the world’s worst nuclear disaster still requires incredible amounts of work.

Apr 22, 2011
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.
Before building the new structures, engineers are clearing the site of contaminated debris like this metal. Highly radioactive equipment and construction waste buried during previous work is being unearthed, and all the sand and gravel used to make the new structures has been brought in from outside. In the background of this photo is the sarcophagus.
Workers pour concrete for the foundations for the towers that will lift the 20,000-ton New Safe Confinement structure into place.
Workers at the site wear protective clothing, masks that filter out potentially radioactive particles, and dosimeters that monitor their daily exposure to radiation.
These 25-meter-long pipes will be hammered into the ground to reinforce the foundation of the New Safe Confinement structure. In the background, a truck carrying gravel is preceded by another that wets the road to keep the dust down. The ground still contains radioactive particles.
Before leaving the site, construction vehicles are steam-cleaned to prevent them from carrying out any radioactive dust.
A worker welds rebar for the New Safe Confinement foundations.
A highly sensitive particulate air sampler monitors the construction site’s overall radiation levels. A worker on the site says that ten days after the disaster at Fukushima, this device picked up wind-borne radioactive dust from Japan.
A critical step in making Chernobyl safer is to decommission the other three reactors on the site. Spent fuel from reactors one, two, and three will be stored in these concrete containers, part of a structure called Interim Spent Fuel Storage Facility 2.