Eleven pillars of precision

19 Mar 2010 - David Wilson, Alignment & Metrology Lead Engineer
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Pillars will be used as fixed reference points to define the global coordinate system for civil engineering works.

This week saw the beginning of construction activity for the installation of ITER's primary survey network, overseen by the Machine Assembly and Installation Section.

The primary survey network consists of 11 permanent survey pillars positioned on the periphery of the worksite. These pillars will be used as fixed reference points to define the global coordinate system for civil engineering works, and to provide a stable reference for monitoring purposes. The network will evolve as the project develops and in the future will provide the global data for an enhanced reference system to be installed within the Tokamak Building.

To ensure the stability of the pillars, they will be constructed around micro piles with foundations in bedrock at a minimum depth of 8 metres. This week, ITER's contractor GDV Ingenieurgesellschaft Holst mbH and their sub-contractor VIT Verbau und Injektionstechnik GmbH have been setting out the position of the survey pillars and installing the micro piles. The construction of the pillars themselves will occur in the next few weeks. Following a period of stabilization, the positions of the survey pillars will be precisely measured.