Manufacturing for the world's largest single-platform cryogenic plant is progressing, with a series of factory acceptance milestones successfully passed (or imminent) and the first completed components expected on site next month.
The LN2 plant (blue, under the responsibility of Europe) will produce liquid nitrogen at a temperature of minus 196 °C to be used as a ''pre-cooler'' in the LHe plant (yellow, procured by the ITER Organization). Nearly 25 tonnes of liquid helium at minus 269 °C will circulate through a five-kilometre network of pipes, pumps and valves procured by India (the first part of the network is shown in green) in order to cool the superconducting magnets, the thermal shield, vacuum cryopumps, and certain diagnostics.
Three parties are sharing responsibility for the procurement of the ITER cryoplant—the ITER Organization, responsible for the liquid helium plant; Europe, in charge of the liquid nitrogen plant and auxiliary systems; and India, whose contractors are procuring the cryolines, the warm lines and cryodistribution components.
Europe is also building the 5,400-m² facility that will house the cryoplant on the ITER site.
Within the frame of industrial contracts signed for the procurement of each package, hundreds of components are currently in late-stage design or fabrication phases. Beginning next month, deliveries will be converging on ITER from factories in Turkey, India, China, Sweden, Czech Republic, Finland, Italy, Japan, and various points in France ... some 450 shipments in all.
The Cryogenic Project Team
expects fully 90 percent of plant components on site by the end of the year, to be stored until the building and technical areas become available for the start of installation activities.
Among recent fabrication milestones, the European Domestic Agency has reported successful factory acceptance tests (FAT) for 85-tonne nitrogen compressors
and a series of turbines
, while two out of the three cold boxes
for the liquid helium plant under ITER Organization procurement are fully equipped and ready for transport. All three of the 137-tonne liquid helium plant cold boxes are expected on site in November.
The cryoplant is composed of helium and nitrogen refrigerators combined with a 80 K helium loop. Storage and recovery of the helium inventory (25 tonnes) is provided in warm and cold (4 K and 80 K) gaseous helium tanks. Three helium refrigerators supply the required cooling power via an interconnection box providing the interface to the cryodistribution system. Two nitrogen refrigerators provide cooling power for the thermal shields and the 80 K pre-cooling of the helium refrigerators. The ITER cryogenic system will be capable of providing cooling power at three different temperature levels: 4 K, 50K and 80K.
A number of unique features will guarantee stable and flexible operation despite unprecedented dynamic heat loads caused by magnetic field variations and fusion neutrons. The plant is also designed to operate over a wide range of ITER plasma scenarios, from short plasma pulses (a few hundred seconds) with 700 MW of fusion power to long plasma pulses of 3,000 seconds with 365 MW of fusion power.
In the build up to the machine's First Plasma, the cryoplant will provide the gradual cooldown and fill of the magnets and thermal shields and the cooldown of the cryopumps that are used to achieve vacuum in the cryostat and vacuum vessel.
Scroll through the gallery below to see images of cryoplant manufacturing. (Photos courtesy of Eric Dupasquier, Air Liquide, unless otherwise indicated.)
Expected at ITER in November
Two of the three liquid helium "cold boxes" are packed for transport to ITER. These vacuum vessels house key components such heat exchangers and turbo-expanders for the process of cooling helium.
Cold boxes: providing insulation for key components
Each 4.2 x 21 metre cold box will weigh about 137 tonnes once all internal components are integrated. Three identical helium plants will store and circulate liquid helium (at a temperature of 4 K or minus 269 °C) throughout the installation.
Last checks on third cold box
In an Air Liquide factory near Grenoble, France, the third and final cold box for the liquid helium (LHe) plant undergoes testing.
Components from all over the world ...
Three parties are involved in the procurement of the ITER cryoplant. Beginning next month, deliveries will be arriving from factories in Turkey, India, China, Sweden, Czech Republic, Finland, Italy, Japan, and various points in France ... some 450 shipments in all. (Pictured: the "warm panels" of the liquid helium cold boxes.)
... Soon to converge on ITER
In a factory in the northeast of France, near Metz, compressor parts for the liquid helium plant are assembled on the shop floor.
4,500 components, all told
The ITER cryogenic system: 50 cold boxes, 3 kilometres of cryolines, and 4,500 components. Ninety percent of components are expected on site before the end of the year.(Pictured: heat recovery skids for the liquid helium plant.)
Construction progresses on 5,400-m² facility at ITER
The site of the ITER cryoplant facility, under construction now by the European Domestic Agency. © EJF Riche (July 2016)
Liquid nitrogen plant components pass factory acceptance tests
Four turbines produced for ITER's liquid nitrogen (LN2) cryogenic plant have successfully passed factory acceptance testing. Photo: F4E
Turbines ... galore
These turbines are destined for the liquid helium plant cold boxes. The liquid helium and liquid nitrogen plants will be housed on a single platform at ITER: a 5,400-m² facility that is under construction now.
Latest good news on liquid nitrogen plant
In a recent milestone, two nitrogen compressors for ITER's liquid nitrogen plant successfully complete factory testing in Europe. Photo: F4E
Before assembly into a larger vessel
European contractors carry out leak tests on 500 metres of linear welds on this 190 m³ inner tank. Photo: F4E
35-metre storage tanks for liquid helium
These quench tanks, procured by Europe, will store liquid helium in the event of a magnet quench—an exceptional event during which magnets lose their superconductivity. Photo: F4E