Nuclear power plant (NPP) risk assessment is broadly separated into disciplines of nuclear safety, security, and safeguards. Different analysis methods and computer models have been constructed to analyze each of these as separate disciplines. However, due to the complexity of NPP systems, there are risks that can span all these disciplines and require consideration of safety-security (2S) interactions which allows a more complete understanding of the relationship among these risks. In this work, a novel leading simulator/trailing simulator (LS/TS) method is introduced to integrate multiple generic safety and security computer models into a single, holistic 2S analysis. A case study is performed using this novel method to determine its effectiveness. The case study shows that the LS/TS method avoided introducing errors in simulation, compared to the same scenario performed without the LS/TS method. A second case study is then used to illustrate an integrated 2S analysis which shows that different levels of damage to vital equipment from sabotage at a NPP can affect accident evolution by several hours.
Risk assessment of nuclear power plants (NPPs) is commonly driven by computer modeling which tracks the evolution of NPP events over time. To capture interactions between nuclear safety and nuclear security, multiple system codes each of which specializes on one space may need to be linked with information transfer among the codes. A systems analysis based on fixed length time blocks is proposed to allow for such a linking within the ADAPT framework without needing to predetermine in which order the safety/security codes interact. A case study using two instances of the Scribe3D code demonstrates the concept and shows agreement with results from a direct solution.
This document details the development of modeling and simulations for existing plant security regimes using identified target sets to link dynamic assessment methodologies by leveraging reactor system level modeling with force-on-force modeling and 3D visualization for developing table-top scenarios. This work leverages an existing hypothetical example used for international physical security training, the Lone Pine nuclear power plant facility for target sets and modeling.
This document details the development of modeling and simulations for existing plant security regimes using identified target sets to link dynamic assessment methodologies by leveraging reactor system level modeling with force-on-force modeling and 3D visualization for developing table-top scenarios. This work leverages an existing hypothetical example used for international physical security training, the Lone Pine nuclear power plant facility for target sets and modeling.
Security at nuclear power plants (NPPs) in the United States is currently based on vital area identification (VAI)-a procedure to determine locations within a nuclear facility that need to be defended from adversaries in order to avoid damage to the facility and/or release of radionuclides to the environment. This procedure heavily leverages a Level 1 probabilistic risk assessment (PRA) which identifies combinations of events that can lead to core damage. Current approaches to VAI for NPPs, however, are determined on a “snapshot-in-time,” and therefore unable to include the time-dependent effects of safety systems within a NPP A novel “leading simulator (LS) / trailing simulator (TS)” methodology is proposed to integrate the thermal hydraulic-based safety analysis of a NPP with a physical security analytical tool to model vital area boundaries and related potential consequences. The methodology will use dynamic event trees to systematically explore the uncertainties in an adversary attack scenario at a hypothetical NPP while incorporating the timing and repair effects that are not captured using the available modeling approaches to physical security practices. Ultimately, the LS/TS methodology will enable NPPs to incorporate the full complement of safety systems and procedures when performing security analyses.
Coupling interests in small modular reactors (SMR) as efficient and effective method to meet increasing energy demands with a growing aversion to cost and schedule overruns traditionally associated with the current fleet of commercial nuclear power plants (NPP), SMRs are attractive because they offer a significant relative cost reduction to current-generation nuclear reactors-- increasing their appeal around the globe. Sandia's Global Nuclear Assurance and Security (GNAS) research perspective reframes the discussion around the "complex risk" of SMRs to address interdependencies between safety, safeguards, and security. This systems study provides technically rigorous analysis of the safety, safeguards, and security risks of SMR technologies. The aims of this research is three-fold. The first aim is to provide analytical evidence to support safety, safeguards, and security claims related to SMRs (Study Report Volume I). Second, this study aims to introduce a systems-theoretic approach for exploring interdependencies between the technical evaluations (Study Report Volume II). The third aim is to demonstrate Sandia's capability for timely, rigorous, and technical analysis to support emerging complex GNAS mission objectives. This page left blank intentionally