Workers have raised the first section of a colossal arch-shaped structure that eventually will cover the exploded nuclear reactor at the Chernobyl power station. Upon completion, the shelter will be moved on tracks over the building containing the destroyed reactor, allowing work to begin on dismantling the reactor and disposing of radioactive waste. The shelter, shaped like a gargantuan Quonset hut, will be 257 meters by 150 meters (843 feet by 492 feet) when completed and at its apex will be higher than the Statue of Liberty. The shelter is to be moved over the reactor building by the end of 2015 - a deadline that no one wants to miss given that the so-called sarcophagus hastily built over the reactor building after the 1986 explosion has an estimated service life of about 30 years. The arch now under construction is only one of two segments that will eventually form the shelter, and so far it's only been raised to a height of 22 meters (72 feet). More structural elements have to be added before it reaches its full height of 108 meters (354 feet), and the work so far has taken seven months. The overall shelter project is budgeted at 1.54 billion ($2 billion) - 1 billion ($1.3 billion) of that for the structure itself - and much uncertainty lies ahead. Even when the shelter is in place, the area around the reactor building will remain hazardous.