Tritium particle balance and retention during DT discharges in JET

The tritium balance based on pressure measurements in the divertor was performed for the DTE1 campaign carried out at JET in 1997. This is a complementary analysis to the integrated tritium inventory already reported for a full day of experiments. The particle balance shows that the T flux retention is about 1.26 × 1021 T s−1 during a plasma pulse (∼65% of the injected flux). Outgasing between pulses reduces this T inventory to about 30% of the injected fluence. This detailed gas balance also shows that the retention of hydrogen species depends on the plasma isotopic ratio. However, during the D clean-up pulses, the amount of T removed by isotopic exchange is shown to be limited to about 2 × 1023 T. Finally, the total particle balance (D + T) is shown to be independent of the plasma isotopic ratio.