A key area of the Small Modular Reactor (SMR) Probabilistic Risk Assessment (PRA) use is in the development of methodologies and tools that will be used to predict the safety, security, safeguards, performance, and deployment viability of SMR systems starting in the design process through the operation phase. Recently, the Idaho National Laboratory (INL) set out to develop quantitative methods and tools and the associated analysis framework for assessing a variety of SMR risks. Development and implementation of SMR-focused safety assessment methods may require new analytic methods or adaptation of traditional methods to the advanced design and operational features of SMRs. The development of SMR-specific safety models for margin determination will provide a safety case that describes potential accidents, design options (including postulated controls), and supports licensing activities by providing a technical basis for the safety envelope. INL has proposed an approach to expand and advance the state-of-the-practice in PRA. Specifically we will develop a framework for applying modern computational tools to create advanced risk-based methods for identifying design vulnerabilities in SMRs. This framework will require the fusion of state-of-the-art PRA methods, advanced 3D visualization methods, and highperformance optimization. The approach has several defining attributes focused within three general areas:
1. Models – A single 3D representation of all key systems, structures, and components (SSCs) will be defined for a particular facility. We will be able to simulate — by understanding how each SSC interacts with other parts of the facility — the hazard-induced susceptibilities of each SSC.
2. Phenomena – An approach to effectively representing hazards and their effect on physical behavior at a facility will need to be determined. In many cases, multiple models of a specific phenomenon may be available, but this ensemble of models will need to be intelligently managed.
3. Integration – Any advanced risk-informed decision support approach will rely on a variety of probabilistic and mechanistic information. The safety, security, and economic drivers will need to be integrated in order to determine the effectiveness of proposed mitigation strategies. We will need to be able to manage all (important) hazards for all (important) scenarios all of the time the facility is in operation.
The focus of the paper will be on discussing the features of the proposed advanced SMR PRA Framework and providing an status update of the development activities.