CHERNOBYL, Ukraine (AP) — A new structure built to confine the Chernobyl reactor at the center of the world’s worst nuclear disaster has been previewed for the media.

Reactor No. 4 at the Chernobyl nuclear power plant in Ukraine exploded and burned on April 26, 1986.

A complex construction effort to secure the molten reactor’s core and 200 tons of highly radioactive material has taken nine years to complete under the auspices of the European Bank for Reconstruction and Development.

Journalists were shown the new safe confinement shelter with all its equipment installed on Tuesday.

The project cost 1.5 billion euros (almost $1.7 billion.) The European Bank for Reconstruction and Development managed a fund with contributions from 45 countries, the European Union and 715 million euros in the bank’s own resources.