Application of HAZOP and LOPA in the risk assessment of TPS LHe system at the NSRRC

The storage ring of Taiwan Photon Source (TPS) at the National Synchrotron Radiation Research Center (NSRRC) will utilize up to four cryogenic supercon-ducting radio frequency (SRF) cavities. These cavities require significant liquid helium cooling to maintain their superconducting state at approximately 4.5 K. Thus, the TPS Liquid Helium Manufacturing System (TPS LHe system) is crucial for providing the necessary cooling and stable pressure. We used Hazard and Oper-ability Studies (HAZOP) and a Layer of Protection Analysis (LOPA) to confirm the safety of the detailed design and the adequacy of risk control measures. The scope of this assessment encompassed the tanks, sys-tems, and pipelines associated with the TPS LHe sys-tem. We analyzed eight nodes corresponding to Piping and Instrumentation Diagrams (P&ID). This analysis resulted in HAZOP worksheets, LOPA worksheets, and a safety instrumented system integrity requirements summary (SIL Level List). Based on the evaluation results, we formulated improvement recommendations to address high-severity potential hazards by modifying internal designs or enhancing protective measures.