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Description
The reliability of the helium cryogenic plant is critical to ensuring the operational availability of the Sirius particle accelerator, as it supplies liquid helium to the superconducting cavities. Commissioned in March 2024, the plant operates at 4.5 K and has a cooling capacity of 816 W. This paper presents an analysis of the main failure events observed during plant operation, as well as their impacts on the superconducting cavities and the storage ring. The analyzed events include failures in the supply of compressed air and electrical power, interruptions in the cooling system, communication failures within the control system, and performance degradation associated with helium contamination. These events resulted in plant shutdowns, cavity interlock activations, helium losses, and extended recovery times, directly affecting Sirius's availability. The analysis enabled the identification of subsystem dependencies and vulnerabilities and supported the development of an improvement plan based on utility redundancy, uninterruptible power supply for critical equipment, continuous helium purification, revision of recovery procedures, and staff training. The results demonstrate how systematic failure analysis can transform operational experience into engineering and maintenance actions to reduce failure recurrence and shorten recovery times, thereby increasing the overall availability and reliability of the accelerator.