Modelling of plasma tritium concentration and wall tritium inventory at JET

In this paper a method for the calculation of the wall particle inventory i n a Tokamak is proposed and applied for a series of discharges carried out during the recent Joint European Torus (JET) D-T experiments, These results are subsequently used to validate a new model for the calculation and pred iction of the wall particle inventory on the pulse by pulse time scale. Thi s model, known as the 'Wall Retention' model, includes the effect of codepo sition and is able to reproduce both the total and the tritium wall invento ry if it is assumed that between 0.8% to 2% of the ion flux to the divertor is codeposited. It is demonstrated that the Wall Retention model can be us ed predictively while maintaining good agreement with the experiments. Extr apolations to ITER give a tritium retention per pulse of 54 g. (C) 1999 Els evier Science B.V. All rights reserved.