Abstract
Steam Generator Tube Rupture (SGTR) is a fault that leads to loss of integrity of primary circuit and bypasses the containment. Its radiological consequence is challenging because of the direct release to the environment and SGTR is one of the most challenging design basis fault for Pressurized Water Reactors (PWR). In addition, only with automatic protections, controlled state cannot be reached. Multiple operator actions are requested following SGTR and it is important to detect and diagnose this fault to reduce operators’ loads.
For the third generation pressurized water reactor, a design target is to maintain the reactor safety within 30 minutes after accident without intervention. Due to the complex operator actions to mitigate SGTR, the action completion time may violate the common assumption in safety analysis. To optimize the mitigation strategy, both transient progress and human factors are taken into account. Based on the mitigation characteristics and human factor analysis for a typical pressurized water reactor, the influence of operator actions on SGTR mitigation is studied. The analyses show that isolation of affected SG is crucial to mitigate this fault and earlier isolation can alleviate the radiological consequence. Optioneering is performed following the analyses performed, and a strategy is proposed to solve potential difficulties in consistence between safety analysis and human factors.
