Subscribe options

Select your newsletters:


Please enter your email address:

@

News & Media

Latest ITER Newsline

  • Challenges | Managing risk in a first-of-a-kind project

    The classic approach to project management is to group risks into three separate categories. The first consists of known risks, the second of unknown risks, and [...]

    Read more

  • Steve Cowley | Projecting into the coming decades

    Steven Cowley, who now heads the Princeton Plasma Physics Laboratory (PPPL), gave a seminar last week at CEA-Cadarache and he had some good news regarding the s [...]

    Read more

  • Outreach | What vacuum does to marshmallows

    Every year in France, science is "à la fête" for two consecutive weekends in October. Free events and demonstrations—tailored particularly to school-a [...]

    Read more

  • Physics | 11th ITER International School announced

    The 11th ITER International School will be held from 20 to 24 July 2020, hosted by Aix-Marseille University in Aix-en-Provence, France. The subject of this year [...]

    Read more

  • Image of the week | An anniversary in blue, white and red

    ITER neighbour and close partner in fusion research, the CEA-Cadarache nuclear research centre, was established in October 1959. This week, it celebrated the 60 [...]

    Read more

Of Interest

See archived entries

Heat removal

Moving 10 tonnes of water per second

If ITER were a fusion power plant, the amount of heat produced by the machine would be partly absorbed by the steam generators and turbines that initiate the electricity-generating process. But ITER is neither a fusion power plant nor a steady-state device: it is an experimental machine designed to demonstrate the technical feasibilityof fusion energy. As it will operate in pulses, the heat production will only occur during relatively brief plasma shots (between five minutes and one hour depending on the regime). And the totality of the heat generated will need to be evacuated, requiring a properly designed heat rejection system.

The installation of 10-metre long shafts for the 13 vertical turbine pumps is underway now. Each pump is designed to move one tonne of water per second. (Click to view larger version...)
The installation of 10-metre long shafts for the 13 vertical turbine pumps is underway now. Each pump is designed to move one tonne of water per second.
Burning plasmas are not the only source of heat in the ITER installation. The compressors and cold boxes in the cryoplant, the transformers and converters in the magnet power conversion buildings, the power supply for the neutral beam injectors ... all this equipment produces significant quantities of heat (although not comparable to that produced inside the ITER Tokamak) that must be extracted at all times through a vast cooling water network comprising kilometres of piping, dozens of pumps, and several thousand valves.

Whatever its source, the cooling water ends up in two 10,000-cubic-metre basins: one "hot," where water is stored before being cooled in the induced-draft cooling tower, and one "cold," which receives the cooled water as it leaves the cooling tower.

The amount of water that needs to be circulated within this system is huge—in the range of 10 cubic metres per second. A set of 13 vertical turbine pumps, submerged deep in the basins, are tasked to move up to one tonne of water per second per pump.

The six-tonne component must be perfectly positioned and balanced to withstand the considerable forces that the rotation of the impeller and the flux of water exert. Horizontal deflection at the bearings cannot exceed 0.05 millimetre. (Click to view larger version...)
The six-tonne component must be perfectly positioned and balanced to withstand the considerable forces that the rotation of the impeller and the flux of water exert. Horizontal deflection at the bearings cannot exceed 0.05 millimetre.
Three of them are dedicated to recirculating the water from the hot basin to the cold basin and balancing the peaks of heat generated by the plasma pulses. Six circulate water from the cold basin through the heat exchangers that receive the heat load from the Tokamak and dump it into the hot basin. Finally, four pumps cool the heat exchangers that take in cooling water from other parts of the installation (cryogenic systems, electric power supplies, etc.).

Installation of the vertical turbine pumps began last week with the insertion, in each pump housing, of the 10-metre-long shaft that will connect the rotor (or impeller) to a powerful 870 kW electrical motor.

In order to withstand the considerable forces that the rotation of the impeller and the flux of water will exert, the component must be perfectly positioned and balanced. The shaft, bearings and impeller are manufactured within 100 microns of tolerance. At the bearings, horizontal deflection cannot exceed 0.05 mm.

Ten shafts are now installed. And the horizontal deflection does not exceed 0.03 millimetres ...


return to the latest published articles