Anytime tritium or deuterium is introduced into a magnetic bottle, the wall materials will become radioactive due to neutron bombardment. It will be impossible for humans to go inside the machine or even come close to it. Robots will be used to replace parts such as blanket modules, to fix leaks and make other repairs, and to examine the interior of the chamber during shutdowns. The robotic equipment itself will be exposed to neutrons. Such remote handling has been used successfully in

the TFTR machine at Princeton (Fig. 8.3) and the JET in England (Fig. 8.4), both of which have used DT fuel. Robots can weld joints by remote control. The first experiments in ITER will use hydrogen or helium, which produce no radioactivity. Later, deuterium experiments will give a small amount of radioactivity. In the next stage, tritium will be used; and the machine will become very “hot.” ITER is much larger than TFTR or JET, and the components to be moved will be large and heavy. Remote handling is expensive and inconvenient, but it does not seem to be a technological barrier.