PII’s Integrated Vulnerability Analysis (IVA) is conducted by PII’s qualified experts in the fields of human errors, procedural errors, process failures, and equipment failures. The IVA starts with the definition of disasters, based upon the significance level of abnormal events. Once the potential disaster events are defined, existing design barriers that confine the consequences are examined. Then, various scenarios with multiple human errors, procedural errors, process failures, and equipment failures able to penetrate the barriers are examined. Errors and failures that can easily induce disasters are identified and corrected. Finally, improvements in design barriers and consequence mitigation will be recommended.