Reactor Vessel Hazard Assessment Case Study

Abstract

Operation of a multi-tubular reactor vessel includes some inherent risks and potential hazards. Multi-tubular reactors tend to be large vessels that contain hydrocarbons under pressure. Some potential hazards that may ensue from potential vessel failure include fragments (i.e., debris), blast loads, and heat. This paper involves the discussion of a case study of a multi-tubular reactor vessel that sustained corrosion cracks on full penetration groove welds near the top and bottom heads. A hazard analysis is conducted that considered various potential scenarios associated with an accidental head failure. The structural response of the vessel is determined using mechanics of materials-based finite element analysis (FEA) models. Blast loads emanating from the vessel as the pressurized water/steam escaped the vessel through a failed opening are estimated. Projectile trajectories for fragments of weldment launched from the failed circumferential weld are also calculated. The results of the models lead to recommended safe standoff distances and potential mitigation options.