Thirty years after the Chernobyl nuclear disaster in Ukraine, a 108-meter-tall, 162-m-long, 257-m-wide steelwork vault began its slide from a safe area to cover the ruined radioactive reactor No. 4. With a 100-year design life, the fully equipped, 36,000-tonne confinement will enclose the reactor building during its removal.. The Novarka joint venture of Paris-based VINCI Construction Grands Projets and Bouygues Travaux Publics assembled and equipped the confinement in two halves more than 300 m from the reactor. Novarka signed its turnkey contract in 2007. Its completion deadline slipped from 2012, and the cost tripled from the original currency to about $1.6 billion. A combination of nuclear hazards, unique engineering, and the involvement of numerous national and international experts and regulators caused overruns, explains Vince Novak, nuclear safety director at the European Bank for Reconstruction and Development, which managed the 40-nation donor fund.