Before revision: Currently the European Spallation Source in Lund, Sweden is under construction to become the world's strongest intermediate duration pulsed neutron source.
After revision: As of 2022, the most powerful neutron source in the world is the Spallation Neutron Source in Oak Ridge, Tennessee, with the European Spallation Source in Lund, Sweden under construction to become the world's strongest intermediate duration pulsed neutron source.