Energy Nuclear Cleanup Twenty-five years after the Chernobyl disaster, the work goes on. by Kevin Bullis June 21, 2011 Sponsored by 1986In the months after the explosion, Soviet authorities organized a construction project that involved remotely operated cranes and almost 100,000 workers. They erected a temporary concrete-and-steel structure to enclose the reactor, even as experts speculated on the possibility of another explosion. The red walls seen here beneath the looming cranes are the beginnings of the structure, which came to be called the sarcophagus. 1986 The explosion scattered highly radioactive chunks of graphite from the reactor’s core over the roof of an adjacent building. Here, a worker scoops up a piece of the hazardous material. Protective lead sheets are tied to his clothes. To avoid radiation poisoning, workers limited their shifts to less than a minute each. 1997Light streams through gaping holes in the makeshift sarcophagus in this view from inside the ruined reactor building. A project undertaken to seal these holes against escaping radiation, and to prop up the walls of the sarcophagus, was finished in 2008. The ruins inside the sarcophagus remain vulnerable. If they collapse, it could become impossible to move buried radioactive materials to a permanent storage facility. April 2011The last Chernobyl reactor, number 3, wasn’t shut down until 2000. The 20,000 containers of spent fuel that had accumulated over the years must be kept cool to avoid a fire that could release radiation. Today, most of the fuel is stored in water under the metal plates in the facility seen here. Tubes containing the fuel are visible in the foreground. (Some of the fuel is still stored in pools at the reactors.) As part of the remediation project, the fuel will be moved into more stable steel-and-concrete casks, which will be slid into the structures shown here. The casks are meant to store fuel safely for 100 years. Workers at Chernobyl wear protective equipment and clothing, even though most of the radiation is contained within the “sarcophagus”—especially now that gaping holes in the sarcophagus have been patched. Soil in the area is contaminated and had to be sorted and stored after it was dug up during the first stages of construction of the new containment structure. View panoramas of the nuclear cleanup at Chernobyl. Subscribe to Continue Reading Uh oh–you've read all five of your free articles for this month. Insider basic Gift $29.95/yr US PRICE Subscribe What's Included Your Gift Includes 1 year (6 issues) of MIT Technology Review magazine in print OR digital format Access to the entire online story archive: 1997-present Special discounts to select partners Discounts to our events Subscribe See international, alumni and other pricing options Already an Insider?Log into your account You've read of free articles this month. Subscribe Become an Insider or Sign in for unlimited access to online articles .