[en] The JET deuterium-tritium experiments in 1997 (DTE1) utilised 20 grams of tritium, produced more than 2.3 x 10²⁰ D-T neutrons, and generated peak fusion powers of 16 MW. Significant health physics input was required to measure and quantify the radiological consequences of high yield neutron and gamma production, and of processing large tritium quantities. This paper summarises the results of radiological protection monitoring carried out during the campaign. Figures are presented of neutron and gamma doses and tritium levels in occupied areas during the D-T operations. Results are given of aerial discharges of tritium and the levels found in the local environment. There has also been potential for measurable tritium exposure in torus operational areas during maintenance and repair activities. Operational health physics knowledge has been gained during work on tritium contaminated systems, and descriptions are given of the initial radiological protection experience of work in areas with high levels of surface and airborne tritium. Initial experience at JET shows that tritium exposure controls have been very effective, giving very low operator doses. JET results also show that the environmental impact of processing 0.1 kg of tritium is not significant. (authors)