CHERNOBYL, Ukraine — Traversing old potholed roads past long-abandoned villages surrounding the site of the world's worst nuclear disaster, you wouldn’t guess there’s a bustling construction site nearby.

The so-called exclusion zone around the Chernobyl nuclear power plant was once home to some 120,000 people, who were evacuated following the reactor meltdown at in 1986. Trees that sprouted in living rooms are now pushing through rooftops inside this highly contaminated, sealed off area, while wild horses and wolves roam the woods.

However, there are also some 7,000 people working here, including almost 3,000 at the plant itself.

An international fund managed by the European Bank for Reconstruction and Development is spending an estimated $2 billion to build a new confinement shelter to protect the world from Chernobyl's radioactivity for the next 100 years.

The existing structure was hastily built after radioactive debris was dumped into the smoldering reactor site one shovel at time by young rescue workers who ran up with heaps of dirt and graphite, then sprinting back before passing out from radiation sickness. Many died.

The shoddy construction of crumbling concrete and rusting metal reflects the communist-era standards of the day.

The new structure is starkly different. Built by a French-led consortium, the 360-foot giant hangar-like casing is being constructed with modern equipment on infrastructure that’s better maintained than in the capital Kyiv, 70 miles to the south. While hundreds in the Ukrainian capital injure themselves every day slipping on ice-covered sidewalks, roads in the exclusion zone are swept clean for a stream of cement trucks.

But not clean enough. Last week, a section of wall and roof of a military hangar adjacent to the destroyed fourth reactor collapsed under a buildup of snow. The structure had been built in 1986, after the first sarcophagus, under standards that have prompted some to call for a new inspection of Ukraine's 20 functioning nuclear reactors, many of which will reach their expiration dates in the next five years.

Officials said radiation levels didn’t rise after the incident. “They didn’t even move toward control norms,” the plant's spokeswoman Maya Rudenko elaborated. Asked what those levels are, however, she chided: “You understand, in a place that suffered from a [highest] scale 7 nuclear accident, there can be no norm.”

“There’s no answer to your question,” she elaborated.

However, in the nearby town of Chernobyl, where most of the administrative buildings and worker lodgings are located, she conceded, 20 millirentgens of radiation per hour is considered normal in winter.

That was the case when GlobalPost visited the site earlier this month. Next to the plant, however, the level jumped above 600.

The highest radiation levels are in the soil, explains Mark, a computer geek in his early twenties who guides tours through the exclusion zone. He's a fan of S.T.A.L.K.E.R, Ukraine's first international hit video game, in which players hunt after irradiated artifacts with supernatural properties, fighting off creatures emerging from murky woodlands.

The beeps from Mark’s Geiger counter speed up when he brushes away a layer of snow. Placed on the ground next to a small tree, its sound is almost continuous — 5,430, the screen flashes — not imminently life-threatening, but you don't want to stick around.

The reactor attracts many visitors. Although tourism here isn’t strictly legal, the authorities allow visits of up to five days, Mark explains. Visitors are registered as scientists doing research. Every self-respecting tourist agency in Kyiv offers tours that cost $120 for locals and $140 for foreigners.

Most Ukrainians have grown used to living in Chernobyl's shadow, which perhaps explains why most media interest is from foreign correspondents. Locals appear especially unconcerned: some 200 people have moved back into the zone, and many others take advantage of its lush pastures and dense surrounding woods for subsistence farming.

Ice on a reservoir once used to cool the reactors is dotted with ice-fishing holes.

Others seek profit any way possible. Marauders, as Mark calls them, first appeared in the late 1980s, sneaking into the zone to steal whatever objects of value were left behind in the rush to evacuate. Last year, eight people were convicted of trying to sell metals with spent uranium, three years after a government official received a similar charge.

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Completion of the reactor confinement structure, set for 2015, will calm longstanding fears about a collapse of the current sarcophagus. Those living around the zone face a less certain future.

Many working-age adults continue to leave the dying villages with rotting communist housing here, where the average monthly salary is $250. Others are succumbing to an HIV epidemic and rampant alcoholism.

The surrounding area’s blight makes it unclear exactly where the exclusion zone ends and “normal life” begins.