The best weld is no weld, says the welder
"The best weld is no weld. But you have to be a welding engineer to say so," Tommi Jokinen, the ITER welding engineer, comments with a smile.
Tommi Jokinen was born in Nokia (yes, that Nokia), Finland.
After his graduation as mechanical engineer in 1995, Tommi worked for the aviation industry. Later he changed to VTT, the Technical Research Centre of Finland where he also did his PhD in laser welding and qualified first as European and later as International Welding Engineer. In 2006, Tommi and his family moved to Garching in Germany to work as VTT contractor for the European Fusion Programme EFDA. His responsibility there was to follow tasks relating to welding mock-ups and the welding process development projects mainly concerning the ITER Vacuum Vessel.
"The main problem with welding thick stainless steel structures up to 60 mm thickness are the distortions," Tommi explains. "In many cases in the ITER machine it will only be possible to access and weld those thick sections from one side. The so-called balance welding, which needs both side access, is thus impossible. This leads to greater distortions. But there are some methods to reduce distortions, for example using narrow gap techniques, which means less material to be melted and thus less distortions. Still, whenever you melt steel by welding you'll get distortions."
His experience in welding of ITER components finally brought Tommi to France, to work for ITER itself. Here he is currently finalizing the welding specifications for the divertor components. Tommi will be working in Cadarache for just one year, nevertheless his family has moved with him. The Jokinens are now living in Pierrevert, the two oldest of their three children (aged 2, 5 and 7) go to the International School in Manosque at the moment and the youngest one will start there in September. "The two years in Germany and now the experience here in France working for the ITER project has been a unique opportunity for me. And for the family it has been great chance to learn new languages and new cultures. We like it here!"
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