Optimization of Reliability in ACP100 Automatic Depressurization System Squib Valve Control System

To address the issue of excessively high probability of failure on demand (PFD) in the squib valve control system of the ACP100 automatic depressurization system, which arises from the inability to effectively identify failures in the latching module constructed using relays and hardware threshold comparison modules, an analysis of the squib valve control system's functionality was conducted. Based on reliability modeling, a sensitivity analysis of PFD was performed to identify the components that have the most significant impact on the PFD of the squib valve control function. Optimization strategies were proposed from a system-wide perspective, aimed at reducing the undiagnosable dangerous failure rate of the latching module or mitigating its effects. Three reliability enhancement approaches were investigated: shortening the periodic test interval, implementing redundant latching modules, and incorporating diagnostic latching logic. The optimized schemes result in a reduction of the PFD average (PFDavg) to less than 1/60 of the original design at most. Notably, the optimization scheme of latching logic diagnosis based on software implementation does not add additional hardware equipment, system design complexity and maintenance complexity.