Dr. Tatsuya Sakurahara Presents at the NPRE 596 Graduate Seminar

NPRE 596 Graduate Seminar

Tuesday, December 11, 2018
4:00 – 4:50 pm – Graduate Seminar – 103 Talbot Laboratory

Tatsuya Sakurahara
Postdoctoral Research Associate
Department of Nuclear, Plasma, and Radiological Engineering
University of Illinois at Urbana-Champaign

Integrated Probabilistic Risk Assessment (I-PRA) Methodology and Computational Platform for Fire PRA of Nuclear Power Plants

Abstract: In resolving emergent safety concerns of Nuclear Power Plants (NPPs), such as the ones created in the aftermath of the Fukushima-Daiichi accident, the existing classical Probabilistic Risk Assessments (PRAs) of NPPs were found to have limitations in generating the required realism for plant risk estimations. Socio-Technical Risk Analysis (SoTeRiA) Laboratory ( at University of Illinois Urbana-Champaign has developed an Integrated PRA (I-PRA) methodological framework that explicitly incorporates the underlying science of accident causation into plant risk scenarios and provides a feasible solution for adding realism to the plant risk estimations. I-PRA provides a unified, multi-level probabilistic integration, starting with the underlying physical and social failure mechanisms, connecting them to the component-level failures, and the system-level risk scenarios in the plant PRA model. While the I-PRA framework is applicable for various safety challenges of concern of NPPs, this presentation provides an overview of the I-PRA methodology and computational platform developed for assessing the plant risk induced by internal fires of NPPs. The Fire I-PRA framework integrates a Computational Fluid Dynamics (CFD)-based fire model with classical PRA through a probabilistic interface, equipped with advanced uncertainty quantification, dependency modeling, and Bayesian updating. In Fire I-PRA, the interactions between physics of fire progression and manual fire suppression are explicitly modeled based on the key timings associated with the fire brigade human performance. The Fire I-PRA has been applied to a realistic fire scenario at an NPP, showing that this new methodology reduces the core damage frequency estimate by 50% compared to the current Fire PRA methodology (NUREG/CR-6850). Improving the realism of PRA can provide NPPs with more design alternatives that can satisfy the risk acceptance criteria.

Graduate Fellowships in NPRE: Apply in Risk Analysis/Power

SoTeRiA Lab encourages graduate students to apply for Graduate Scholarships and Fellowships under the Power area, with a focus on Risk Analysis. NPRE has several opportunities for scholarships and fellowships:

If you are interested in this path, contact us at


Mohaghegh is Chief Scientific Investigator and a representative of the United States in the coordinated research project, “Methodology for Assessing Pipe Failure Rates in Advanced Water Cooled Reactors.” The International Atomic Energy Agency (IAEA), which assists research for peaceful uses of nuclear energy and the development of practical applications throughout the world, is sponsoring the project.

This IAEA team brings together experts from academia, industry, and regulatory agencies from eight countries, including Canada, Germany, Korea, Lithuania, Malaysia, Russia, Tunisia, and the United States. The four-year project’s objective is to develop new methodologies to estimate pipe failure rates in advanced water cooled reactors for improved safety designs.

Mohaghegh and Justin Pence, an NPRE graduate research assistant, recently attended the project’s first meeting held June 12-14, 2018, in Vienna, Austria. Mohaghegh and Pence introduced SoTeRiA Laboratory’s proposed methodology on the prediction of pipe failure rates, discussed future plans for the projects, and helped to establish a unified plan for the four-year scope of the project.

Read the full story here:



Originally Published here:

By Doris Dahl & Justin Pence.  Published on November 28, 2017

The disaster at the Fukushima Daiichi Power Plant in Japan and the catastrophic Macondo oil spill in the Gulf of Mexico are bitter reminders of the critical need to create innovative scientific solutions for risk management, risk-informed decision making, and regulation. Zahra Mohaghegh, an assistant professor of nuclear, plasma, and radiological engineering (NPRE) and a member of the Organizational Intelligence and Computational Social Science Group, is helping position Illinois to become a global leader in socio-technical risk analysis.

Mohaghegh’s goal is clear. “At Illinois, we want to develop the research and educational infrastructure that will help solve the most challenging risk and safety issues of industries,” Mohaghegh said. To meet this goal, she is advancing probabilistic risk assessment (PRA).

PRA is the leading methodology for estimating the systematic risk for high-consequence industries and is a constantly changing technology that can meet the demands and challenges of complex socio-technical systems and processes. “Next-generation leaders must begin to think differently, using risk-informed solutions to initiate safe, resilient, sustainable, and socially responsible technological advancements to usher in an era void of technological accidents,” Mohaghegh said.

Since its inception at the Massachusetts Institute of Technology, PRA is now one of the key pillars of the risk-informed regulatory framework for the Nuclear Regulatory Commission. Other government agencies, including the Department of Energy (DOE), the Federal Aviation Administration, the National Aeronautics and Space Administration, the Department of Defense, the Environmental Protection Agency, the Food and Drug Administration, and the Department of Transportation, also have begun to adopt PRA for decision making and policy setting.

A concurrent trend is the expansion of PRA research and educational programs at an increasing number of universities in the U.S. and abroad.

After completing her postdoctoral research appointment in 2011 at the Center for Risk and Reliability at the University of Maryland, Mohaghegh created a risk management consulting company in Boston. She made the move to academia in 2013 to fulfill her desire to teach and to interact with students through research.

“Although building a new area has its challenges, the criticality of the topic in high-consequence industries and the societal benefits of its applications will enable Illinois students with highly competitive skillsets to fill the growing demand for risk analysts,” Mohaghegh said. “I believe that the collaborative research environment of  Illinois will give me the opportunity to make this university a global leader in socio-technical risk analysis.”

She has diligently worked toward this goal—establishing the Socio-Technical Risk Analysis (SoTeRiA) Laboratory, where a multidisciplinary team of students, researchers, and industry professionals are advancing PRA with scientific innovations in two key areas: spatio-temporal causal modeling of social and physical failure mechanisms in PRA, and the fusion of big data analytics with PRA.

When Mohaghegh joined the NPRE faculty, she transferred a large-scale industry research project sponsored by the South Texas Project Nuclear Operating Company to Illinois. During the last four years, Mohaghegh and her graduate students have been developing an integrated risk methodology for the resolution of a 20-year longstanding safety issue in the nuclear industry, the Generic Safety Issue 191, which is related to the performance of the emergency core cooling system following a loss of coolant accident.

Mohaghegh became affiliated with the Beckman Institute in 2014, and the collaborative environment has helped her further her research in the field. As a Beckman faculty member, Mohaghegh has initiated collaborations with other Beckman groups, proposing new areas of discovery on the topics such as fire PRA, risk-informed emergency response, health care risk analysis, and monetary value of risk analysis, which assists companies and organizations to make decisions that not only promote safety but also helps their profitability.

In 2015, Mohaghegh became the principal investigator (PI) of a five-year National Science Foundation (NSF) grant to quantify organizational factors using big data analytics in PRA, and in 2017, she became the PI for a three-year DOE grant for enterprise risk management to promote the sustainability of the U.S. nuclear fleet.

With recent support from the College of Engineering, Mohaghegh is establishing the SoTeRiA Industry Affiliates Program (IAP), the first program in academia that works with industry for risk analysis and offers the latest research methods for real-time risk detection, monitoring, mitigation, and risk management with big data applications, while providing risk-analysis training. The SoTeRiA Laboratory has initiated collaborations with national and international research institutions and plans to expand risk analysis collaborations through the program to develop tailor-made solutions for high-risk operations around the world. Industry members will work with the SoTeRiA IAP team to build specialized tools for solving their most challenging problems, while developing training series that fit their business needs.

“Risk analysis will be advanced by creative, scientific, and multidisciplinary students who have the interest and support to explore and study courses among diverse engineering and non-engineering departments,” Mohaghegh said. “The Beckman Institute embodies this model and it is through this style that a university can enable the nonlinear cross-
disciplinary thinking needed to analyze the risks emerging at the interface of social and technical systems.”




Mohaghegh Awarded DOE NEUP Grant to Investigate Systematic Enterprise Risk Management

Read Original Article HERE

Envision a future in which nuclear power companies use intelligent decision-making support systems to estimate scenarios of system failure or revenue loss. Managing physical and social failure mechanisms, these systems would provide key importance measures on how to mitigate potential undesirable consequences.

In such a future, the nuclear industry could enter a new era void of catastrophic accidents, making nuclear energy cleaner, more profitable, and more sustainable.

The Department of Energy (DOE) Nuclear Energy University Program (NEUP) has awarded Assistant Professor Zahra Mohaghegh and her research team, the Socio-Technical Risk Analysis (SoTeRiA) Laboratory, a three-year, $800,000 grant to pursue this vision.

Entitled “Systematic Enterprise Risk Management by Integrating the RISMC Toolkit and Cost-Benefit Analysis,” the project will promote U.S. nuclear fleet sustainability by developing a systematic scenario-based Enterprise Risk Management (ERM) technology. The SoTeRiA group’s undertaking will satisfy short- and long-term regulatory design standards, improve safety, create cost savings and avoid production losses.

In this project, Probabilistic Risk Assessment (PRA), integrated with the Idaho National Laboratory (INL) Risk-Informed Safety Margin Characterization (RISMC) Toolkit, will be used to quantify uncertainty nodes. The SoTeRiA team will work with INL risk experts to conduct a first-of-its-kind physics-social hybrid framework for quantifying long-term nuclear power plant enterprise risk scenarios.

As the Principal Investigator (PI) of this project, Mohaghegh will work with collaborators from the College of Law at Illinois, the South Texas Project Nuclear Operating Company (STPNOC), ABS Consulting, and Texas A&M University. The project continues a line of research called “Monetary Value of PRA” that the PI, in collaboration with Co-PIs Arden Rowell, professor of Law at Illinois, and NPRE scientist Ernie Kee, began for analyzing the business value of risk-informed decision making for nuclear power plants and other complex systems.

Building a risk analysis ecosystem at Illinois, the SoTeRiA Laboratory has initiated projects in several other areas of PRA to meet demands faced by industry, including:

Tatsuya Sakurahara Receives Illinois Student Government’s Teaching Excellence Award

Congratulations to our very own Tatsuya Sakurahara for being an Excellent Teaching Assistant in the Field of PRA. See the Full Article HERE.

Sakurahara has been recognized for his dedication as a teaching assistant in two NPRE courses on Probabilistic Risk Assessment (PRA), NPRE 461 (Probabilistic Risk Assessment) and NPRE 498/598 (Advanced Risk Analysis), which Mohaghegh instructs. The ISG awards five Teaching Excellence Awards each year to recognize excellence in teaching and to show appreciation for outstanding University of Illinois instructors.

Tatsuya is an integral part of our laboratory, and we are so proud to see him recognized for his teaching excellence.

See the Full Article HERE.

Dr. George Apostolakis on Risk-Informed Regulatory Decision-Making: March 7th at UIUC

Probabilistic Risk Assessment (PRA) is a key pillar in the Risk-Informed Regulatory Decision-Making framework of the Nuclear Regulatory Commission (NRC). A growing number of other U.S. government agencies are evaluating the use of PRA for decision making and policy setting. Dr. George Apostolakis, former Commissioner of the NRC has had a distinguished career as a professor, an engineer, and risk analyst. During his time at the NRC, he headed the Risk Management Task Force, whose purpose was to “develop a strategic vision and options for adopting a more comprehensive, holistic, risk-informed, performance based regulatory approach” (Apostolakis, Cunningham, Lui, Pangburn, & Reckley, 2012). In the taskforce’s seminal work, NUREG-2150, a vision for the evolution of PRA in Regulatory Decision-Making is laid out, and a Risk Management Regulatory Framework for improving safety and security in high-consequence industry applications is proposed.

As a research team dedicated to advancing PRA, the Socio-Technical Risk Analysis (SoTeRiA) Laboratory contributes to the vision put forth in NUREG-2150, to develop risk models that provide “credible accident sequences by considering the facility or operation as a “system of systems” consisting of structures, systems, components, and personnel” (Apostolakis et al., 2012). Due to the socio-technical nature of risk in complex systems, SoTeRiA Laboratory has initiated several areas of research to meet demands faced by industry, including; risk-informed emergency preparedness, planning and response modeling for severe accidents, fire PRA, location-specific Loss-Of-Coolant Accident (LOCA) frequency estimations, global risk importance measures, modeling the effects of human and organizational influences on technical system failure, estimating the monetary value of PRA, , and developing a risk-informed resolution of Generic Safety Issue 191, a long-standing issue for commercial nuclear power plants and the NRC. In a time where over-standardization in regulations is an important topic in the public narrative, risk-informed approaches can have significant impacts on safety improvements, cost-reductions and sustainability of high-consequence industries.

The Honorable George Apostolakis will present at the University of Illinois Urbana-Champaign Grainger Lecture Series on March 7th, at 12:00 p.m. in Talbot Laboratory Room 103. Please see the flier below for more information.


Later in the day on March 7th, at 3:00 PM in Beckman Institute 2269-2nd Floor Tower Room, there will be an Informal Student Discussion with Dr. Apostolakis where students are encouraged to bring questions and discuss their multidisciplinary research.

See Flier Here



Apostolakis, G., Cunningham, M., Lui, C., Pangburn, G., & Reckley, W. (2012). A Proposed Risk Management Regulatory Framework. NUREG-2150, US Nuclear Regulatory Commission, April.