Visualizing primary cooling system risks with bowtie diagram for RSG GAS operator guidance

Abstract

The G.A. Siwabessy Multipurpose Reactor (RSG GAS) is a pool‐type research reactor. When the reactor operates, the heat released in the core is removed by the primary cooling system. It is necessary to evaluate this system, because failure can cause worst events such as the melting of reactor fuel and the release of radioactivity to the environment. Due to the possibility of radioactive material releases, safety issues are important to be evaluated. Several studies using event tree analysis (ETA), fuzzy fault tree analysis (FFTA) describe the results quantitatively. The varied educations of operators will provide various responses to quantitative results, and a need to create qualitative results that are simple and easy to understand using bowtie analysis that visualizes the risk scenario. Failure of this system causes loss of coolant accident (LOCA) and loss of flow accident (LOFA). The results show that the relationship between the consequences and causes of the risk occurrence LOCA and LOFA, and the controls used to prevent and reduce the hazard based on safety and emergency system at RSG GAS, can be depicted in a bowtie diagram. The bowtie diagram is simple and easy for an RSG GAS operator to carry out their duties and increase awareness regarding the safety of reactor operations.