2014-04-27. Chernobyl: Capping a Catastrophe.

posted Apr 28, 2014, 2:33 PM by Alan Gould
For GSS Energy Use chapter 4. Excerpt: Chernobyl, Ukraine. Against the decaying skyline here, a one-of-a-kind engineering project is rising near the remains of the world’s worst civilian nuclear disaster. An army of workers, shielded from radiation by thick concrete slabs, is constructing a huge arch, ...by 2017 the 32,000-ton arch will be delicately pushed on Teflon pads to cover the ramshackle shelter that was built to entomb the radioactive remains of the reactor that exploded and burned here in April 1986. ...The arch will also allow the final stage of the Chernobyl cleanup to begin — an arduous task to remove the heavily contaminated reactor debris for permanent safe storage.  ...With nations debating the future of atomic power as one way to reduce greenhouse-gas emissions and fight climate change, the arch is also a stark reminder that nuclear energy, for all of its benefits, carries enormous risks. When things go wrong, huge challenges follow. Containment and cleanup push engineering capabilities to their limits, as Japan is also finding out since the meltdowns at the Fukushima power plant three years ago. The costs are enormous — the Chernobyl arch alone will end up costing about $1.5 billion, financed largely by the United States and about 30 other nations. And making the site of a radioactive disaster truly secure can take generations. ...The Chernobyl accident can be likened to a huge dirty bomb, an explosion that spewed radioactive material in all directions ... followed by a fire that sent even more contaminants into the atmosphere that were then carried by winds across the region and into Western Europe. ...at Three Mile Island in Pennsylvania in 1979 and Fukushima in 2011... reactor cores melted down, but the core material — the nuclear fuel — remained within protective containment structures. The four reactors at the Chernobyl plant had no such containment.  ...An exclusion zone of about 1,000 square miles still exists around the plant, with access controlled through checkpoints. ...the zone remains virtually empty. Many of the villages were bulldozed;  ...equipment had become so radioactive during the initial cleanup that it had been simply buried in place. ...Mr. Korneyev, 65, a radiation specialist and native of Kazakhstan, ... understands more than most people the extent of the radioactive mess that remains in what was Unit 4. While the number of radioactive particles released during the explosion and subsequent fire was enormous, they came from only about five tons of the reactor fuel. Close to 200 tons of fuel — uranium and its highly radioactive fission byproducts — remain in the bowels of the destroyed building. ...Mr. Korneyev, the radiation specialist who knows better than most the conditions in the sarcophagus, has enormous doubts about the long-term project. “There is not the technology available to access this fuel inside the unit,” he said....  http://www.nytimes.com/interactive/2014/04/27/science/chernobyl-capping-a-catastrophe.html. By Henry Fountain, The New York Times.