25 Feb (NucNet): A number of key milestones, including a firm basis for the design, have been achieved at the US Oak Ridge National Laboratory for the construction of the world’s largest pulsed electromagnet.
The magnet of the solenoid type will be used to initiate and maintain the plasma current within the International Thermonuclear Experimental Reactor (Iter) and will be located at the centre of the so-called ‘tokamak’ or magnetic confinement in which plasma is contained in a doughnut-shaped vacuum vessel.
The solenoid will weigh 1,000 metric tons and be about 18 meters (60 feet) tall. It will store about 5.5 gigajoules of energy.
The solenoid will be composed of six stacked modules, each made of conductor wound into pancake-like layers.
An individual module weighs more than 110 metric tons and manufacturing will take 16 to 24 months per module.
Each module, plus a spare, must be fabricated and tested at full current of 45 kiloampere and temperature of 4 kelvin (about minus 269 degrees Celsius), to ensure that the superconducting magnets are ready to perform in the environment of the ITER machine.
A central solenoid mock-up module, which will verify the production process, is planned for completion in summer 2015, with sample conductor winding activities beginning in summer 2014.
The mock-up module will be made at 40 percent of the actual Iter module height and will not be superconducting.
All modules are scheduled for completion by February 2019 to meet the international Iter schedule.
Iter, under construction at the Cadarache nuclear site in southern France, is intended to demonstrate the scientific and technological feasibility of fusion power. It will be the world’s largest experimental fusion facility.
Iter is a first-of-a-kind global collaboration. Europe will contribute 45 percent of its construction costs, while the other six members to the venture (China, India, Japan, South Korea, Russia and the US), will contribute equally to the rest. The total cost of the project has been estimated at 15 billion euros (about 20 billion US dollars).
