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On the afternoon last year when the team from the European tokamak JET attempted first plasma after an 18-month shutdown,  Francesco Romanelli remained in his first-floor office. "I wasn't expecting the machine to perform so faultlessly on its first attempt," he later explained. "Besides, things had a way of going wrong when I entered the room, so maybe it was better after all."

 

That anecdote and others were related by Romanelli at last week's Inside ±¬×ߺÚÁÏ seminar, during which he gave a first-hand overview of the ±¬×ߺÚÁÏ-like wall campaign that has been running at JET since that first (very successful) day back in August 2011. Three thousand installable items and 16,000 tiles had been replaced in the machine (non-metal carbon tiles were replaced by the metals beryllium and tungsten) to equip JET with the same materials mix chosen for ±¬×ߺÚÁÏ.

 

Romanelli reported in detail on the experimental results so far: demonstration of low fuel retention, tungsten divertor successfully tested, observations related to the dynamics of disruptions ...

 

"Overall, the operation of the ±¬×ߺÚÁÏ-like wall has been easier than expected, giving us the confidence that the fusion community is making the right choice for ±¬×ߺÚÁÏ. We see JET as the main risk mitigation measure in support of ±¬×ߺÚÁÏ."

 

The European Fusion Development Agreement is already looking ahead to other roles for JET—developing plasma scenarios in ±¬×ߺÚÁÏ-relevant configurations and testing the compatibility of the wall with the use of tritium. "JET can provide unique input in a number of technical and operational areas."

 

David Campbell, director of ±¬×ߺÚÁÏ's Plasma Operation Directorate, agrees: "The crucial ±¬×ߺÚÁÏ-like wall experiment will give us insight—ahead of ±¬×ߺÚÁÏ operation—as to how fusion plasmas will behave in the presence of the plasma-facing mixture that we're planning to use in ±¬×ߺÚÁÏ."