You're reading: Chornobyl, 27 years later, still dangerous

CHORNOBYL, Ukraine – A turbine hall adjoining Chornobyl’s destroyed fourth reactor has a gaping 600-square meter opening where the roof collapsed in February. The roof has not been fixed yet, letting in rainwater that mingles with radioactive dust and elements inside and oozes out.

The roof of the turbine hall was erected in 1986 to cover up the building that was damaged as a result of the April 26 nuclear explosion in the reactor, the worst in human history. The roof consisted of nine slabs of steel, each weighing 41.5 tons. It was mounted in post-explosion haste and has not been maintained for 27 years.

Eight of the slabs remain a time bomb and can also collapse, according to the power plant’s management. “The new roof was put on top of the old roof. Unfortunately, the fatigue of the steel has taken place – this means the steel was worn out,” said Ihor Gramotkin, head of the Chornobyl nuclear plant.

The station is still trying to figure out how to patch the hole and maintain the roof safely, but insist there is no danger for anyone outside the station because the level of radiation inside the turbine hall is relatively low and is now being monitored.

Fixing the roof will be a temporary solution, though, until the fourth reactor is covered with a new, safer confinement in 2015. Its construction is an international project with a budget of $2 billion. It’s implemented by Novarka, a joint venture of two French companies. It’s being built at a special platform nearby, and will be slid over the 4th reactor by specially designed rails.

The broken roof in the turbine hall of Chornobyl power plant.

A scheme displaying the location of the broken roof.

“Previously there was a discussion among scientists about whether the new sarcophagus is needed, but this necessity became obvious after the roof accident in February. The sooner it is built the better,” says Gramotkin.

The roof of the turbine hall of the fourth reactor collapsed on Feb. 12, forcing both Novarka and Chornobyl nuclear power plant to evacuate its workers. They insisted that there was no danger of radiation, except the dust cloud that was caused by the falling. It was decontaminated shortly after, according to the power plant’s staff.

Two special inter-agency commissions concluded a month later that the roof collapsed “as a result of a multitude of negative factors.” In their joint report they list seven such factors, and heavy snowfall in February is not on the list.

Investigators found that the original construction of the roof took place with a number of violations. For example, the metal plates were not mounted properly on their support structures, and were not joined up like they were supposed to be, according to the drafts.

“The way the work was conducted was not very precise, but I think in those conditions nobody could do better,” says Oleksandr Novikov, deputy director of plant safety. “And I think it’s a great achievement that for nearly 27 years the roof has held.”

The staff at the power plant had no idea, however, about those errors because the  roof over the turbine hall has not been examined or maintained since its construction. All the effort went into maintaining the fourth reactor, covered by a concrete casing, often referred to as “the sarcophagus.” Underneath it are still 190 tons of nuclear fuel in various stages of decomposition.

The casing needs a lot of attention because its concrete, exposed to high levels of radiation, is crumbling much faster than originally projected. Gramotkin says some of the cracks are up to a meter in width, letting in rainwater and snow.

The turbine hall, however, has a much bigger gap, which is still being studied. “We’re conducting detailed research, but you have to understand that (humans) can only work there for half an hour to get an annual dose of radiation,” Novikov says.

He says that the station is still trying to figure out how to let humans into the building, possibly with the protection of lead shields. “I have this principle: there will be no more liquidators in Chornobyl,” he says.

There were 600,000 liquidators working in Chornobyl to combat the aftermath of the nuclear explosion. Many of them received high or even fatal doses of radiation.

Gramotkin hopes that despite the complications, the collapsed roof of the turbine hall will be patched up by next winter.

Kyiv Post editor Katya Gorchinskaya can be reached at [email protected] and staff writer Svitlana Tuchynska at [email protected].