Safety in the ARIES tokamak design study

The ARIES-I (Advanced Reactor Innovation and Evaluation Study-I), the first of three in a series of potential tokamak reactors, will use He at 5 MPa as a blanket coolant, and SiC/composite ceramic for the first wall and blanket materials. The coolant and the structural material were chosen for their low activation, both in the short term after accidents and for long term waste management. The breeder Li₄ SiO₄ (with LiAlO₂ as a backup choice) was also chosen for low activation. Contemporary plasma physics and aggressive technology are used in ARIES-I, resulting in very high (24-T maximum at the coil) toroidal fields (TF). The stored TF energy will be about 130 GJ. Safely discharging the stored energy under electrical fault conditions and preventing a failure in the magnet set from propagating into systems containing radioactive inventories are central concerns. The TF coil system consists of 16 coils, each containing two separate windings powered by two independent power supplies. Arcs and shorts between the two power supply systems and across individual windings have been modeled. Delay or failure in circuit breaker opening has been modeled. The safety impacts of LOCA (loss-of-coolant accident). LOFA (loss of flow), and disruptive events have also been evaluated