Engineering Design of 1 MJ HTS SMES System With kA-Level Current Capacity for NICA Accelerator

The high-quality power supply is crucial for the stable operation of the Nuclotron-based Ion Collider fAсility (NICA), which could experience frequent energy fluctuations (1–2.6 MJ). The superconducting magnetic energy storage system (SMES), characterized by high power density and fast response, holds significant advantages. Placing it between the power supply system and the main ring of accelerator can suppress power oscillations and facilitate the controlled energy release of the superconducting magnets in accelerator under fault conditions. Meanwhile, superconducting coils wound with conductors on round core (CORC) cable exhibit low inductance and high current density, making them well-suited for SMES magnet. Therefore, this paper introduces the SMES system manufactured using CORC cables. Eight solenoid coils are coaxially assembled to manufacture the HTS magnet. The critical current of the HTS CORC coils is 12 kA. For the forced-flow cooling, each coil has its own channel to avoid the drop pressure in single channel. For excitation, the coils are connected in series, reducing the power supply requirements. Following the manufacture of CORC prototype coil, the results from the experiments in liquid nitrogen indicate that the critical current has reached the expected value. This implies that the HTS magnet wound with CORC cables can meet the operational requirements of the SMES system.