WI AB657

Creates a sales and use tax exemption for equipment, materials, and technology used exclusively for qualified nuclear fusion technology projects certified by the Wisconsin Economic Development Corporation (WEDC)

Defines "qualified nuclear fusion technology project" as a project undertaking controlled fusion of atomic nuclei or related research, including energy generation, propulsion systems, medical isotope production, and plasma physics research

Exempts 73 categories of items from sales tax, including superconductors, electromagnets (0.1 tesla or more), high-voltage power supplies (1,000+ volts), vacuum systems, tritium and deuterium fuel, cryogenic systems, and specialized construction materials

Extends the exemption to contractors who purchase qualifying items that become components of a certified fusion project

Takes effect on the first day of the third month after publication