The Socio-Technical Risk Analysis (SoTeRiA) Research Laboratory in the Department of Nuclear, Plasma and Radiological Engineering (NPRE) at the University of Illinois Urbana-Champaign is developing Probabilistic Risk Assessment (PRA) technologies for advanced reactors with the International Atomic Energy Agency (IAEA) under the Coordinated Research Project (CRP) award I31030, “Methodology for Assessing Pipe Failure Rates in Advanced Water Cooled Reactors.” This research is also partially supported by the U.S. Department of Energy, Office of Nuclear Energy University Program (NEUP), Reactor Concepts Research Development and Demonstration (RCRD&D) under Award #17-12614.
This IAEA project brings together experts from academia, industry, and regulatory agencies from eight countries, including Canada, Germany, Korea, Lithuania, Malaysia, Russia, Tunisia, and the United States. In summer 2020, Associate Professor Zahra Mohaghegh, who serves as a Chief Scientific Investigator and representative of the United States in this IAEA project, and Research Assistant Professor Tatsuya Sakurahara attended the third Research Coordinated Meeting (RCM) for this CRP. Other SoTeRiA members supporting this IAEA study include: Graduate students Wen-Chi Cheng and John Beal; Research Associate Ernie Kee and Research Scientist Seyed Reihani.
The successful deployment of a new fleet of advanced reactors requires innovative techniques to estimate safety and risk metrics with consideration of uncertainties induced by new designs and lack of operational data. In this IAEA project, the SoTeRiA Research Laboratory developed an Integrated Probabilistic Physics-of-Failure (I-PPoF) methodological framework to couple the physical degradation phenomena with models of maintenance work processes (e.g., in-service inspection, leak monitoring systems, and repair and replacement). While the new risk-informed methodology, developed by SoTeRiA, can be applicable for various types of advanced reactors, this IAEA study investigated the pipe failure rate estimation for a dissimilar metal weld in the cold leg of an AP 1000 advanced water-cooled reactor that was subject to Primary Water Stress Corrosion Cracking (PWSCC).
Typically, risk assessment is performed using empirical data from operational databases or experiments, but by opening the risk assessment to deeper levels of physics of failure, the SoTeRiA laboratory is able to provide a better understanding of risk for advanced reactors. In addition to physics of failure, the SoTeRiA laboratory models the organizational issues inherent in socio-technical systems. For example, maintenance practice and management’s direction of the maintenance work often reveal the most important locations for failures of in-service equipment. These new risk-informed methodologies can help disclose failure paths in existing nuclear power plants and in new reactor designs, leading to more cost-effective risk management action.
SoTeRiA’s other ongoing research projects on advancing PRA for the deployment of new technologies, funded by the Department of Energy (DOE); on organizational risk analysis, sponsored by the National Science Foundation (NSF); and research projects on advancing fire PRA, and the risk-informed resolution of Generic Safety Issue, led by the nuclear industry, can be found on the SoTeRiA Lab website: http://soteria.npre.illinois.edu/research/