The fusion reaction releases neutrons, the energy of which will be used in future power stations to heat water to heat drive the power plant. The neutrons would be quite dangerous to humans, but when the plant is turned off the production of neutrons ceases within milliseconds.
The neutron bombardment also affects the vessel itself, and so once the plant is decommissioned the site will be radioactive. However the radioactive products are short lived (50-100 years) compared to the waste from a fission powerplant (which lasts for thousands of years). Also, the radioactivity in a fusion powerplant will be confined to the powerplant itself.