The existing sarcophagus on the Chernobyl nuclear power station has long been insecure. Now a new coffin is intended to ensure that the reactor remains safe for centuries.
The official date for the start of construction is April 26, the 26th anniversary of the Chernobyl reactor disaster. That's when work should start on a new sarcophagus for Block 4 of the nuclear power station. The existing one was put up in a hurry in the first few months after the accident.
The explosion in 1986 caused the world's worst nuclear accident
In April 1986, the Chernobyl nuclear power plant suffered a melt-down and an explosion which led to the release of several tons of radioactive material. The accident was caused by an experiment which went wrong, as well as by a number of serious construction faults in the Soviet RBMK-type reactor.
It is still not known how many people died as a result. The International Atomic Energy Agency and the World Health Organization talk of 4,000 fatal cancers among the emergency staff as a result of exposure to radiation. Environmental organizations like Greenpeace say that this is a trivialization: they estimate the death toll is ten times greater.
Sarcophagus to last 100 years
The existing concrete mantle was already considered to be in danger of collapse in the 90s. The new one should last at least 100 years. A new consortium, Novarka, was founded to carry out the project, including the French Vinci and Bouygues, the German Nukem and Hochtief, and several Ukrainian companies. Novarka won the Ukrainian government contract in 2007, for a project which is expected to cost around a billion euros ($1.32 billion). Much of the money for the "Chernobyl Shelter Fund" (CSF) comes from the European Union, but the US, Canada, Japan, Ukraine and other countries are also contributing.
The existing mantle is no longer secure
The new sarcophagus will measure 257 meters (281 yards) across and be 109 meters high, and it will weigh 29,000 tonnes. Because of the high level of radiation, the new containment cannot be built directly over the existing one. It will have to be built on a neighboring plot of land and then shunted into its final position.
Construction is set to be completed in summer 2015, but the Ukrainian prime minister, Mykola Asarov, hopes that it will be ready earlier. He told journalists: "We want to solve the problem in one and half years."
Uncertainty about waste disposal
The administration of the power station says that the existing concrete mantle has to be stabilized before construction starts. It says that, once the new sarcophagus is ready, radioactive material from inside the ruined reactor will be recovered and removed.
But the Ukrainian nuclear expert Vladimir Usatenko is skeptical. He points out that no-one has the slightest idea how dangerous the power station and its ruined Block 4 really are. "The information about the amount of remaining fissile material in Block 4 was falsified after the accident," he told DW, "as was all the data about the situation in the power station." All the plans to make the power station safe, he says, are based on uncertain data.
Just a cover up?
Yuriy Kostenko thinks that the new mantle will merely cover up the problems
Originally all that was intended was to stabilize the existing mantle and remove the radioactive material from Block 4, according to Yuriy Kostenko, former environment minister and head of the Ukrainian delegation which negotiated with the G7 countries in the 90s. That is when talks about securing the reactor started. He told DW that Ukraine had had neither the funding nor the technology to do that. "It's ended up so that, now, all the problems will simply be covered with a new sarcophagus," he says.
In fact, the plan includes the possibility of removing the old mantle sometime in the future, once the new one is in place. That's when the remaining radioactive material would be removed, without allowing any radiation to get into the environment.
Authors: Alexander Sawitzki, Markian Ostaptschuk / mll
Editor: Greg Wiser