29th Symposium on Fusion Technology (SOFT 2016)

P2.087 Thermohydraulic and Quench Behaviour of the JT-60SA Toroidal Field Coil in Cold Tests Facility

6 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 87

Poster E. Magnets and Power Supplies P2 Poster session

Speaker

Sylvie Nicollet (IRFM)

Description

The Toroidal Field system of the JT-60SA tokamak comprises 18 NbTi superconducting coils. In each TF coil (TFC), 6 Cable-In-Conduit Conductor (CICC) lengths are wound in 6 double-pancakes (DP) and carry a nominal current of 25.7 kA at a temperature of 5 K. These coils are tested in the Cold Test Facility (CTF, CEA Saclay), the test program including a quench for each of the first coils of the two series (ASG and GE). In order to ensure the tested magnet safety, a regular quench detection system is based on compensated voltages. A SuperMagnet (CryoSoft) model has been developed, each of the 12 Pancakes being modelled by THEA (Thermal, Hydraulic and Electric Analysis) with its own friction factor, heat exchange coefficient, magnetic field and heat input. The cryogenic circuit is modelled with the FLOWER code (Hydraulic Network Simulation) comprising the pump, heat exchanger, heater, relief valves, and quench tank. The experimental quench performed on C10 coil has been simulated, representing the increase of inlet helium temperature up to 7.46 K and the quench on side pancake DP6, followed by the safety current discharge. The calculation results are compared with the tests measurements signals: the helium temperature, pressure and mass flow at the extremities of the conductors and coil. The additional calculated parameters are presented: the conductor temperature, the current sharing temperature, the normal length, the resistance and the resistive voltage. Results regarding the external cryogenic loop are also detailed. Particular attention is paid to mass flow, pressure and temperature signals to assess the feasibility of a possible secondary quench detection of thermo-hydraulic nature in the JT-60SA Tokamak. Theses experiments and simulations can also help validating similar models used for ITER magnets quench studies and safe operation.