The nuclear crisis in Japan has refocused attention the world over on nuclear safety. In Europe, many can still remember the Chernobyl disaster, which is considered the world's worst nuclear accident.

Ukraine, where the nuclear plant is located, will mark the 25th anniversary of the meltdown this month, while efforts to deal with the aftermath are still very much underway.

Concerns over Chernobyl center on the shell, which is meant to keep in radioactivity from the ruined plant. The sarcophagus, as it is called, has developed cracks and holes and is no longer considered reliable.

On Tuesday, representatives from more than 50 countries came together in the Ukrainian capital, Kyiv, to announce pledges of around 550 million euros ($785 million) to finance a new structure to contain the radiation. Yet the sum was more than 100 million euros below the target.

Ever-present danger

Significant work must still be done at the plant.

Greenpeace nuclear expert Heinz Smital says radiation levels at Chernobyl are 100 times higher than normal. "These radiation levels aren't coming from the ground but rather directly from the reactor, through the meter-thick concrete casing," he says.

The sarcophagus was hastily erected after the explosion at the plant. Now, it is nearing the end of its lifespan and has been letting rain and melted snow in and radiation out. In 2008, steel support beams were installed to prop up the dilapidated walls of the old structure and quell the water leakage.

Julia Marusich from the Chernobyl plant's Department of International Cooperation says a lot of faith has been placed in the support beams. "This construction was meant to stabilize the protective cover for 15 years. So from 2008, we have these 15 years of security and time to work on a new shell," she says.

But work on the huge project has been more complicated than expected - the new steel sarcophagus was meant to be in place by 2007. Now, many feel 2015 is a more realistic timeframe.

Heinz Smital from Greenpeace says an immensely complex task lies ahead: "It's not possible to build the new shell directly over the Chernobyl reactor. The radiation around the site is just too high to do any work there. So it has to be built much further away and placed on rails, making it the largest mobile object ever built, at 29,000 tons. Then, it has to be moved and placed over the reactor."

Slow progress

Work on the new shell and the rail link is still in the preliminary stages. Highly contaminated soil must first be removed to minimize the radiation risk for workers. Also, only around 5 percent of the plant's nuclear fuel was released in the 1986 explosion, so there are fears of what may still lie inside the crumbling reactor.

"That means 95 percent of the fuel is still in there," says Smital. "More and more of this is disintegrating into dust, which means we have significant levels of radioactive dust which must be located and contained."

The Ukrainian government has said it needs around 700 million euros for the project, which is why the international community has jumped into the picture. The European Union, in particular, still views the reactor as a serious risk.

While the funding announced at the conference in Kyiv on Tuesday was not as much as had been hoped, it should nonetheless go a long way to kick-starting the next construction phase for the new sarcophagus. But with only 13 years to get it in place, time is of the essence.

Author: Christina Nagel /dfm
Editor: Nancy Isenson