4. CFETR CSMC and testing facility
● Develop magnet technology of CFETR Nb3Sn CS;
● Carry out experiments onelectromagnetism, magnetism, thermodynamics performance of magnets under fastmagnetic field environment;
● Evaluate the safe operationcharacteristics of magnets.
SystemDescription and main parameters
The CSMC magnet testing facility consists offollowing systems as shown in following layout.
Cryostat,provides the high vacuum and adiabatic operation environment for thelarge-scale magnet. The dimension of the Dewar is that the diameter is around7.7 m, and the height is greater than 11 m.
Vacuum system, is used for obtaining the high vacuum. It mainly consists of roots pumpunits and molecular pumps.
Power supplies are composed of a 50 kA/250V two-quadrant and a 50 kA/3k V four-quadrant powersupplies used separately for the DC and AC test operation including the cyclictest.
Cryogenic system, provides the cooling medium for test magnet and other cryogeniccomponents. The supercritical helium (3-7 bar, 20 g/s) is used for maintainingthe operation temperature of the magnet at 4.5 K.
Current leads and feeder system, has two pairs of high temperature superconducting(HTS) current leads with current carrying capacity of 52 kA.
Quench detection andprotection system, provides the effective quench detection and protection in conditions ofstrong magnetic coupling, high magnetic energy and strong electromagneticinterference, and the accuracy of the detection system can reach 99.99%. OPDR (Distributedoptical fiber sensing) technology should be first installed to protect the CSMC HTS lead system.
Diagnostic control system, controls all subsystems of the magnet testing platform during the test.The parameters such as temperate, pressure, mass flow, etc. will be monitored.
To demonstrate the CFETR CS coil operation scenarios whichrequest to charge the coils up to the operation current of 47kA, and themaximum magnetic field to 12T with a rump rate up to 5T/s without quench.
Explore the major properties of CFETR CSMC, e.g. the electricperformance tests, thermal hydraulics, AC losses, quench behaviors
Up to 1000-cycle operation will be carried out to verify the CFETR cs coilsdesign and manufacturing technology in the magnet and the demonstration ofCFETR cs coil operation scenarios.
New, effective, and novel quench detection andprotection technology will be developed and fully tested to meet the requirementfor CFTER CS.
The main parameters of CSMC
Inner diameter of coil: 1500 mm
Operating current: 47 kA
Operating temperature: 4.5 K
Resistance of joints: <5 nΩ
Maximumchange rate of magnetic field: 5 T/s
●High accuracy forced helium(SHe) temperature controllersystem;
●High accuracy forced helium(SHe) mass flow measurement.
●Develop novelquench detection schemes and reliable quench protection .
●HTS insert coil tests using the strong backgroundmagnetic field generated by CSMC
●To evaluate a performance degradation theNb3Sn superconducting magnets in associated with high-currentmulti-coils pulsed operation;
●To demonstrate the CFETR CS coil operationscenarios and analysis;