I never said it was. But a device that needs multiple square feet of high tensile steel to hold together will have immense costs because it also includes gigantic superconducting magnets, vats of cryo-coolant and myriad of custom, unique parts made of exotic materials for exorbitant money.

The billion price tags of tokamak experiments is not a scientific oddity, it's a fundamental economic issue with the approach that will carry on to any production plant, that as far as we can conjuncture will need to be even larger and more expensive.