A giant arch shielding radioactive waste from the 1986 Chernobyl nuclear disaster began sliding into place Monday with a mission of keeping the site safe for generations to come. The European Bank for Reconstruction and Development (EBRD) - the project's main sponsor - is planning to complete the installation on November 29 at a total cost of 1.5 billion euros ($1.6 billion). At least 30 people were killed on the site of the accident in Ukraine, at the time a Soviet republic. The world's worst man-made disaster left thousands dead or dying of radiation poisoning over large swathes of the western part of the former Soviet Union.