Imagine a metal arch that, at its highest point, is taller than the Statue of Liberty. Now picture it sliding along the ground for a distance of about three football fields, making it the biggest movable structure ever built. Under this steel rainbow, engineers are planning to entomb the site of the worst nuclear accident in history, at the Chernobyl power plant in the Ukraine, using robotics to dismantle the ruins and permanently seal the wreckage.

After reactor number 4 exploded at the plant on April 26, 1986, sending radioactive dust as far as Japan and the U.S., the Soviet Union put up a structure of steel and concrete, commonly known as the sarcophagus, over the reactor to contain the radioactivity. “It was really quite a remarkable feat, but after 25 years, it’s in danger of collapse,” explains civil and environmental engineer Eric Schmie­man of the Battelle Memorial Institute. The structure, which was put up as quickly as possible to limit worker exposure to radiation, was never meant to last forever.

It was designed “like a house of cards,” Schmie­man says, with pieces of metal leaning against one another and hooked together. “There are no welded joints or bolted joints—it wouldn’t take much of a seismic event to knock it down.”

French construction company Novarka is working on a replacement, the New Safe Confinement (NSC), which Schmieman helped to design. Because the reactor is still radioactive, ­architects designed the NSC with worker safety in mind. The arch will not be built over the ­sarcophagus but will be ­assembled nearby from prefabricated segments. Workers will use hydraulic jacks to slide the arch about 300 meters along Teflon bearings until it covers the sarcophagus. Once engineers seal the reactor, they will remotely maneuver three robotic cranes inside the NSC to dismantle the sarcophagus and reactor and to clean up any leftover radioactive dust.

Novarka aims to finish fabricating the NSC by the summer of 2014, at a cost of $2.1 billion from 29 countries. It is expected to last at least 100 years.

This article was originally published with the title Steel Rainbow.

7 Comments

1. 1. lamorpa 03:31 PM 4/26/11

   Ready in what sense? Ready to be built?

   Reply | Report Abuse | Link to this

2. 2. bobhiggins 07:25 PM 4/27/11

   Uh, potentially impressive but as yet uncompleted engineering feat that should have been unnecessary.

   Reply | Report Abuse | Link to this

3. 3. acomfort 02:15 PM 4/30/11

   The radiation may last over 10,000 years but this cover will only last 100 years. This means we will need to build at least 100 more covers. This will be great for the someones GDP. acomfort

   Reply | Report Abuse | Link to this

4. 4. Elderlybloke 03:57 AM 5/1/11

   acomfort,
   
   The radiation will be a lot less in 100 years I expect.
   It "may" last over 10,000 years = so what level are you talking about - Sweet FA I think.

   Reply | Report Abuse | Link to this

5. 5. acomfort 12:52 PM 5/1/11

   Elderlybloke,
   I see different half life numbers given for different materials and I chose 10,000 years to make a point not to be scientific.
   Here is another number you could use <snip> "Radiation lives almost eternally; its half-life is some thirty thousand years," <snip>
   From: http://tinyurl.com/3v5fna3
   
   acomfort

   Reply | Report Abuse | Link to this

6. 6. DmyLen 05:59 PM 5/1/11

   Very interesting article! I do have a few corrections though: The country is called Ukraine, not "the" Ukraine. And the correct spelling is Chornobyl not "Chernobyl". It would be nice to see the Ukrainian transliteration of Ukrainian cities instead of the Russian versions, especially in a post-Soviet world.

   Reply | Report Abuse | Link to this

7. 7. acomfort 07:24 PM 5/3/11

   Here is a statement about how many times the tomb will have to be rebuilt by
   "John Mann <takedeadaim@hotmail.com>"
   
   "The site remains so dangerous the new entombment structure must be built away from the Chernobyl reactor. The plan is to then move it over the exploded reactor remains on rails, then seal it. This new tomb is designed to last a century - when it will have to be replaced again. The law of entropy insures it must be repeated indefinitely."
   
   acomfort

   Reply | Report Abuse | Link to this