There are some big challenges that still need to be met, such as how to breed tritium in the blanket, how to make the reactor realistically serviceable, materia

There are some big challenges that still need to be met, such as how to breed tritium in the blanket, how to make the reactor realistically serviceable, materials resistant to sputtering, etc. Nearer-term are solutions to problems of how the diverter effects plasma flow, but even that is a long way out.