Tritium contamination studies involving test materials and JET remote handling tools

To determine the potential contamination of remote cutting and welding tools to be used in the Joint European Torus (JET) torus after the introduction of tritium, experiments were performed using these tools on Inconel pipe specimens which were exposed to elemental tritium (HT) at a concentration of 4.6×10¹⁰ Bq/m³. A maximum tritium release of ~15600 Bq was measured during welding, resulting in a 0.5-Bq/cm² surface contamination of the tool. A second series of tests was performed in order to determine the degree of surface contamination of various materials when exposed to HTO as a function of the exposure time and the relative efficacy of different decontamination techniques. Stainless steel, aluminum alloy, and rigid PVC were exposed to HTO (liquid) at a concentration of 4.4×10¹⁰ Bq/l for 1, 24, and 120 h, and then decontaminated. The decontamination techniques used included leaching in water, baking at 1000°C, hot air stream, and weathering. The maximum levels of tritium surface contamination measured during the test were ~12 Bq/cm² for stainless steel, ~5 Bq/cm² for aluminum alloy, and ~1700 Bq/cm² for PVC. A decontamination factor of about 80% (as measured by smears) was achieved using a hot air stream at 125°C for stainless steel and aluminum alloy, and baking at 100°C for PVC