What exotic materials? Molten salts and steel is most of it. These reactors have essentially 0% chance to have airborn escape of radiation. An fusion reactors

What exotic materials? Molten salts and steel is most of it. These reactors have essentially 0% chance to have airborn escape of radiation. An fusion reactors don't actually run on basic elements. The require a fuel that is specially breed. And when they operate they have radioactive materials that can go airborn.