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So far, so good for ITER neutral beam design work | 01/05/2013
One of CCFE's design projects for ITER passed a key review with flying colours earlier this month.
A team of five engineers from Culham went to Cadarache for the Preliminary Design Review of the ITER neutral beam system's Beam Line Vessel and Beam Source Vessel. These components will be welded together to form a large steel case housing the tokamak's neutral beam heating system. This is a lot more complicated than it sounds – and designers have to make sure that the vessels adhere to French nuclear regulations, as well as passing stringent stress analysis, including seismic analysis to show they can cope with ‘worst case scenarios' like earthquakes.
CCFE is working on the Beam Line Vessel and several other components of the ITER neutral beam line. The Spanish fusion association Ciemat is also involved as a third party, designing magnetic shielding components for the neutral beam system. Three years in, the projects are nearing completion and the Preliminary Design Review is a major milestone confirming that they are on track. This just leaves the Final Design Review in a year's time as the last hurdle to be negotiated before the procurement of components can begin.
“We were pleased with how the review went – the outcome was positive for CCFE,” says Robin Stafford-Allen, one of the project team. “The number of design comments was small and the panel expressed satisfaction with the work that CCFE and Ciemat have done.”
CCFE is involved in a number of consortia that have been awarded contracts to develop ITER systems by the European domestic agency Fusion for Energy. Other areas covered include neutronics (the study of how fast fusion neutrons affect surrounding materials), ion cyclotron resonance heating, and studies for magnetic diagnostics.
In the case of the neutral beam vessel design, the Culham team have been able to use experience from JET systems – a JET neutral beam injector is pictured left – although everything is a lot bigger on ITER.
“We're scaling up to something more than twice as big as JET and dealing with one million volts instead of 130,000 volts,“ explains Robin. “Also, the neutral beam will inject negative ions, whereas JET uses positive ones, a big difference in itself. So while similarities exist, there is a lot to get your teeth into as a design engineer.”
Although the two-day review panel left little time for viewing the ITER construction site, Robin got an impression of the strong activity happening at Cadarache:
“The civil engineering is moving ahead and is well beyond the ‘hole in the ground’ stage. And opening an autonomous ITER site at Cadarache, including the headquarters building, has brought benefits. The whole project is a mammoth undertaking but our team is glad to be playing a small part in bringing the ITER machine to life.”