{"id":331,"date":"2015-03-18T18:11:30","date_gmt":"2015-03-18T16:11:30","guid":{"rendered":"http:\/\/ua-green.org\/?p=331"},"modified":"2015-03-19T09:10:47","modified_gmt":"2015-03-19T07:10:47","slug":"english-chernobyl-containing-the-world-s-worst-nuclear-accident","status":"publish","type":"post","link":"https:\/\/ua-green.org\/en\/english-chernobyl-containing-the-world-s-worst-nuclear-accident.html","title":{"rendered":"Chernobyl: Containing the world’s worst nuclear accident"},"content":{"rendered":"\"01\"<\/a><\/p>\n

Rising above the scene of the world\u2019s worst nuclear accident is the spectacular sight of the largest moveable structure ever created on land.<\/p>\n

The complex of nuclear power plants at Chernobyl has dominated this corner of northwest Ukraine for decades but the new construction towers over it all.<\/p>\n

The project is to build what is called a New Safe Confinement \u2013 in effect, a giant cover, a kind of dome, to fit over the building that houses the reactor that exploded on 26 April, 1986.<\/p>\n

The radiation immediately above the reactor is still far too intense for the new enclosure to be built exactly where it is needed \u2013 anyone working there can only stay very briefly.<\/p>\n

So adjacent land has been cleared and then decontaminated \u2013 a massive task in itself \u2013 to allow the new structure to be assembled before being manoeuvred into position.<\/p>\n

Sealed future<\/h4>\n

Large enough to accommodate a couple of Boeing 747s or the Stade de France in Paris, and almost tall enough to hold St Paul\u2019s Cathedral in London, the giant cover stands on a system of massive rails.<\/p>\n

When complete, it will weigh an extraordinary 31,000 tonnes.<\/p>\n

Over several days, it will be rolled along its special track so as to just slide over the reactor building \u2013 a very tight fit \u2013 in order to seal it in.<\/p>\n

The task is \u201cof a complexity and uniqueness we have never faced before\u201d, according to Vince Novak, who runs the nuclear safety department of the European Bank for Reconstruction and Development. He has led the international drive to make Chernobyl less dangerous.<\/p>\n

\u201cUntil this project is in place, we will not be safe,\u201d he said during a media visit to the site.<\/p>\n

\u201cThe ultimate objective is to protect the environment, contain the threat and deal with the radioactive material inside.\u201d<\/p>\n

Dangerous mix<\/h4>\n

This material is a nightmare mix of more than 100 tonnes of uranium, one tonne of plutonium, and other highly radioactive elements, formed into a previously-unseen lava-like mass.<\/p>\n

Added to that are several thousand tonnes of sand and boron dropped on to the site by emergency workers at the time.<\/p>\n

Vast quantities of radioactive liquids and dust are also present inside a reactor building that has itself long been in danger of collapse.<\/p>\n

In the months following the accident \u2013 when the reactor exploded and burned for 10 days \u2013 the authorities attempted to smother the building in an emergency \u201csarcophagus\u201d of concrete and steel.<\/p>\n

But this was only ever intended to be a temporary fix and has needed urgent repairs to try to keep it stable and intact.<\/p>\n

One of the shift managers working at the power station back in 1986 \u2013 though not on duty when the disaster struck \u2013 told me how that weakness of the building is a serious concern.<\/p>\n

According to Lenar Sagidulin, the emergency concrete was \u201cjust stuck to the side of the building; it was not stable.<\/p>\n

\u201cAll this structure could just collapse, suddenly. There are cracks and holes growing in size, so this new confinement is a good idea and will meet its intended functions.\u201d<\/p>\n

The confinement system involves some seriously challenging engineering \u2013 it\u2019s designed to withstand a magnitude 6 earthquake, a Category 3 tornado and temperature extremes ranging from -43C to +45C.<\/p>\n

A double skin creates a cavity between the inner and outer walls that helps regulate temperature and humidity, and a complex ventilation system uses a system of negative pressure to keep any radioactive dust trapped inside.<\/p>\n

The goal is not merely to enclose the damaged reactor and isolate it from the corrosive effects of the weather – but also to create a space in which to start the job of dismantling the most hazardous components.<\/p>\n

Suspended from the apex of the structure will be remotely operated cranes, designed to tackle tasks too hazardous for human beings.<\/p>\n

During the assembly phase, the radiation risk has been minimised by the construction of a protective wall right beside the reactor building.<\/p>\n

This means the workforce at the assembly site receive minimal doses of radiation.<\/p>\n

The man in charge of the project\u2019s management, Ron Hink, joked that he probably gets a higher dose while flying home to Kentucky.<\/p>\n

But he acknowledges a greater risk during a crucial stage of the forthcoming operation to install the new structure.<\/p>\n

Donor gap<\/h4>\n

Although the walls at each end have been shaped to fit over the contours of the reactor building\u2019s roof, teams of workers will still need to be on hand to make sure of a tight seal.<\/p>\n

Mr Hink said: \u201cThat\u2019s probably the most hazardous job we have here. That work is inside the structure and that is fairly high-dose and will require a lot of workers to execute.<\/p>\n

\u201cThey will work on a 15-on, 15-off rotation so they will only work half the month.\u201d<\/p>\n

Coming up with the design has involved a long and difficult journey. Initially, Russian experts favoured smothering the whole building in a massive tomb of concrete \u2013 until the risks of corrosion and cracking were highlighted.<\/p>\n

Then came the task of raising funds for such an expensive project \u2013 currently priced at 1.5bn euros for the confinement system, with a total bill for repair and safety work at the site of 2.15bn.<\/p>\n

As things stand, the EBRD has committed 675m euros, with the European Commission providing 361m. The third largest donor is the United States with 241m. Ahead of a donors\u2019 conference next month, there is a funding shortfall of $100m.<\/p>\n

The hope is to have the new structure in place and fully commissioned by November 2017.<\/p>\n

If that is achieved, it would be 31 years since the disaster itself \u2013 but should provide protection for at least a century.<\/p>\n

bbc.com<\/a>","protected":false},"excerpt":{"rendered":"

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