29th Symposium on Fusion Technology (SOFT 2016)

P3.088 On optimization of air cooling system of FDR dissipating energy from ITER magnet coils

7 Sep 2016, 11:00

1h 20m

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

Board: 88

Poster E. Magnets and Power Supplies P3 Poster session

Speaker

Victor Tanchuk (JSC "NIIEFA")

Description

The Fast Discharge Resistors (FDR) under development at NIIEFA are intended together with switching equipment to dissipate energy released in case of quench of the ITER superconducting coils, thereby protecting them against failure. FDRs are made of sections consisting of resistive elements enclosed in boxes. Two-four sections stacked vertically form a separate module. During energy release the resistive elements are heated to 250-300⁰С practically adiabatically. The resistors should be cooled to their initial temperature within 4-6 hours. For this purpose the air cooling system based on the use of natural air circulation in the system of channels formed by supply and return pipes, vertical modules and chimneys has been developed. The numerical simulation of the cooling process revealed that distribution of the air flow in the parallel channels formed by the vertical modules is considerably non-uniform, which essentially increases the module cooling time. Contrary to the expectations the proposed measures on optimizing the air cooling system, while mitigating the negative effect of air flow non-uniformity in the FDR modules, did not provide the specified 4-6 hours for cooling of the resistors. Therefore, despite evident advantages of the natural air circulation used for cooling of the resistors (saving of equipment, space and energy) the authors were compelled to consider the resistor cooling system based on the forced air circulation produced by blowers. The reported analysis continues previously performed studies of the FDR cooling system. The idea to apply the forced air circulation in the resistor cooling system and to install diaphragms in each module to equalize air flow in the cooled-in-parallel modules made it possible to reduce the time for their cooling to the specified values without a considerable reconfiguration of the air cooling system.