Overview of deuterium-tritium nuclear operations at JET

Two unique high-performance Deuterium-Tritium (DT) campaigns were performed at JET in 2021 and 2023 producing more than 1.5·1021 14.1 MeV neutrons. These campaigns not only achieved breakthroughs in fusion energy but also provided unique opportunities for integrated testing of a nuclear tokamak operation in DT. An outstanding amount of nuclear fusion-related data has been collected through EUROfusion technological exploitation of JET DT operations. Started within the JET3 project and continuing in the 'Preparation of ITER Operations' (PrIO) work-package, the experiments aimed to enhance nuclear technology understanding, validate codes and data, and optimize nuclear operations at ITER. Neutronics experiments explored activation of real ITER materials, damage to functional materials, water activation in a tokamak cooling loop, and effects on electronics. Benchmark experiments validated computational tools and nuclear data for ITER nuclear analyses. The acquired experience is crucial for ITER nuclear phase, safety demonstrations, and DT-2 licensing, making the JET DT results highly valuable for ITER program advancement. The paper provides a comprehensive overview of activities, emphasizing key findings, achievements, lessons learned so far, issues, and outcomes for the ITER program, licensing, and nuclear operations.