INTRODUCTION OF A SATURATED BATH IN VINCENTA MODELS: APPLICATION TO THE CRYOGENIC SYSTEM FOR JT-60SA TOKAMAK

The CEA is involved in large helium refrigeration applied to the future experimental fusion reactors (e.g. ITER or JT‐60SA). Pulsed operation of such machines results in heat load variations which the refrigerators have to cope with. One solution to smooth pulsed loads is to use a large thermal buffer, and in the case of JT‐60SA cryogenic system, a saturated thermal bath is one of the investigated solutions. A 1D thermo hydraulic model describing the cooling loop associated with TF (Toroidal Field) coils and TF casing has been developed using Vincenta code to calculate the heat load arriving to the buffer (saturated bath). However, the liquid helium buffer itself and its coupling with the primary loop was not modelized. This paper shows results obtained using the existing functionalities in Vincenta code to model a saturated bath. For very large bath volumes, bath temperature remains almost steady and the power removed is equal to those previously calculated. On the other side, for smaller buffer volumes (e.g. JT‐60SA scheme), it has been found that the increase of temperature fluctuations does not vary proportionally with the decrease of the buffer volume.The CEA is involved in large helium refrigeration applied to the future experimental fusion reactors (e.g. ITER or JT‐60SA). Pulsed operation of such machines results in heat load variations which the refrigerators have to cope with. One solution to smooth pulsed loads is to use a large thermal buffer, and in the case of JT‐60SA cryogenic system, a saturated thermal bath is one of the investigated solutions. A 1D thermo hydraulic model describing the cooling loop associated with TF (Toroidal Field) coils and TF casing has been developed using Vincenta code to calculate the heat load arriving to the buffer (saturated bath). However, the liquid helium buffer itself and its coupling with the primary loop was not modelized. This paper shows results obtained using the existing functionalities in Vincenta code to model a saturated bath. For very large bath volumes, bath temperature remains almost steady and the power removed is equal to those previously calculated. On the other side, for smaller buffer volumes ...