The completion of the 9,300 m² B2 slab on 27 August concludes four years of work (2010-2014) to create a ground support structure for the Tokamak Complex. (ITER Organization)

ITER, the international fusion project, has entered a new phase of construction following the completion of the concrete basemat that will support the tokamak complex.

Workers have now started to frame out the lower walls of the seven-storey structure that will house the fusion experiment, and the start of concrete pouring is ‘imminent’ the ITER Organization says.

"The start of pouring activities for the massive tokamak complex is an important and exciting moment for the ITER Project," said ITER director-general Osamu Motojima. "Years of hard work by all ITER Members are bearing fruit as the ITER facility takes shape in France and as the manufacturing of the systems and components advances. ITER is progressing on all fronts."

The milestone follows the completion of the 1.5-meter thick concrete basemat, which began in August 2010 and required investment of some EUR100 million from F4E, the domestic agency responsible for Europe’s contribution to ITER.

The basemat construction was carried out by a group of companies led by GTM SUD and under the supervision of F4E and the ENGAGE consortium consisting of Assystem, Atkins, Empresarios Agrupados and Egis.

From August 2010 to August 2014, workers excavated a 17-metre-deep, 90x130m Tokamak Complex Seismic Pit; created a ground-level basemat and retaining walls; installed 493 seismic columns and pads; and poured the foundation slab. This foundation slab will support the 400,000 tons of building and equipment for the seven-storey tokamak complex.

Construction of the tokamak complex is now the responsibility of a French-Spanish consortium VFR under a EUR300 million contract, awarded in December 2012 by Fusion for Energy. The consortium includes French companies VINCI Construction Grands Projets, Razel-Bec, Dodin Campenon Bernard, Campenon Bernard Sud-Est, GTM Sud and Chantiers Modernes Sud, and the Spanish firm Ferrovial Agroman.

At 80m tall, 120m long and 80m wide, the Tokamak Complex will require 16,000 tons of rebar, 150,000 m³ of concrete and 7500 tons of steel for the building structure.

Photo: The completion of the 9300 m² B2 slab in August concludes four years of work to create a ground support structure for the Tokamak Complex. (Credit: ITER Organization)