A subterranean river runs through the ITER installation

14 February 2020

A subterranean river runs through the ITER installation. Rushing through 60 kilometres of piping, passing through dozens of pumps, filters and heat exchangers at a rate of up to 14 cubic metres per second, its flow is more than half that of the nearby Verdon River. This ramified network is tasked with cooling and evacuating the heat generated by ITER operation—one main loop designed for the Tokamak proper, the other for the installation's auxiliary systems.

Cooling this considerable flux of water requires a massive installation based on simple principles: heat exchange, evaporation, and re-condensation.

The efficiency of the cooling process depends on the surface through which the heat is exchanged. Hot water entering the cooling cells is sprinkled by a set of 4,540 spray nozzles into a stack of corrugated plastic sheets called "fill pack." If unfolded, the total exchange surface provided by the fill pack would be on the order of 704,000 square metres, the equivalent of some 70 football fields.

If ITER were an industrial fusion plant, the heat in the plasma-facing wall would be converted into electricity by way of steam generators, turbines, and alternators.