skip to main content

NPRE News

Mohaghegh Brings Socio-Technical Risk Analysis Perspectives to Nuclear Power Safety

Mohaghegh Brings Socio-Technical Risk Analysis Perspectives to Nuclear Power Safety

11/19/2012 2:10:00 PM Susan Mumm

Scientists need to consider how social and technological elements interact when searching for ways to ensure nuclear power safety, said new NPRE Assistant Prof. Zahra Mohaghegh.

Beginning in January 2013, Mohaghegh will join NPRE with “a desire to enhance safety of nuclear power plants and, to benefit society by reducing the probability of accidents and incidents in complex, high-risk engineered systems.” She hopes "to make scientific contributions to the fields of risk and reliability, in general, and more specifically, to develop advanced methodologies and techniques for Probabilistic Risk Analysis (PRA)."

Zahra Mohaghegh, left, receiving the George Apostolakis Fellowship Award from the International Association of Probabilistic Safety Assessment and Management (PSAM).
Zahra Mohaghegh, left, receiving the George Apostolakis Fellowship Award from the International Association of Probabilistic Safety Assessment and Management (PSAM).
The genesis of PRA was the landmark Reactor Safety Study (RSS) published in 1975. “Since then, PRA has grown into an accepted technical discipline with a wide range of applications,” she says. “PRA can provide input for risk-informed decision making for the design, operation, and regulatory oversight of complex systems.”

According to Mohaghegh, risk-informed activities include new reactor licensing, life extension and power upgrade decisions for the current generation of plants, operational decisions regarding maintenance, system upgrades, inspections, and assessment of operational events (Significant Determination Process, and Event Assessment Program). Mohaghegh adds that even the traditionally deterministic disciplines, such as Thermal Hydraulic (TH) and accident phenomenology modeling, have found value in incorporating probabilistic thinking (examples include TH code uncertainty evaluation and fire phenomenology uncertainty).

Despite significant methodological advancements, new methods for PRA are needed, Mohaghegh said. “If we want to preclude catastrophes, we need to more formally and comprehensively integrate the interactions of social and technical systems in risk assessment. We need to incorporate the underlying failure mechanisms of both physical and social elements of risk scenarios into a socio-technical risk analysis framework.”

Mohaghegh’s background in Mechanical and Reliability Engineering and her expertise in social sciences provide her with the necessary foundations to advance the state of the art in socio-technical risk analysis of complex systems, with an emphasis on nuclear power safety. Through new research, she intends to “bridge the gap between engineers and social scientists to more realistically model risk.”

As an example of socio-technical issues, Mohagehgh argues that “we have witnessed the gaps in safety culture as significant risk contributors to many major accidents such as Three Mile Island and Chernobyl and, the recent disasters at Fukushima and the Gulf of Mexico. However, there has not yet been any consensus among industry, academia, and regulatory organizations regarding the best approaches to assess safety culture and how to model its impact on technical systems risk.”

“Socio-technical risk analysis is very challenging, but vital if we are to proactively reduce the possibility of rare, but catastrophic accidents,” Mohaghegh notes. Because of the multidisciplinary and complex nature of this topic, she mentions that this type of research will need “(1) a cross-disciplinary team of experts from academia and industry for expansion of the modeling boundaries, (2) more effective use of computational power and simulation, and (3) improvement in information-sharing technology for large-scale collaborative modeling and analysis.” Her short-term research objective is to “provide some of the key building blocks of socio-technical risk analysis.”

Mohaghegh obtained her B.Sc. in Mechanical Engineering from Sharif University of Technology in Tehran. Her undergraduate thesis was on the evaluation of effective parameters for the efficiency of combined cycle power plants. After graduation from Sharif, she worked as a research engineer in the largest power plant research institute in Tehran, and came to understand the extent of influence of organizational factors on the performance of complex technological systems. This experience motivated her to pursue graduate studies (master’s and Ph.D.) in the United States at the University of Maryland in Reliability Engineering, during which she also completed graduate courses in Industrial & Organizational Psychology, Business, and Public Policy.

The focus of her doctoral research was on the extension of PRA in order to include the effects of human and organizational factors. She developed a “multi-level framework, called SoTeRiA (Socio-Technical Risk Analysis), as a theoretical foundation for the integration of technical system PRA models with both the social features (e.g., safety culture) and the structural aspects (e.g., safety practices) of the organization operating the system.”

Mohaghegh argues that “because of the multidisciplinary nature of socio-technical risk frameworks, using a single modeling technique is insufficient.” She pioneered the integration of Bayesian Belief Network, (a probabilistic tool), and System Dynamics, (a deterministic method), with the classical PRA techniques as an example of the SoTeRiA framework. The originality and practicality of her doctoral research was recognized by the Zonta International Amelia Earhart Award.

During her post-doctoral work at the Center for Risk and Reliability at the University of Maryland, she worked on “another building block for a socio-technical risk analysis: incorporation of underlying physical failure mechanisms into PRA.” Her research shed light on the critical aspects of the “interactions of physical failure mechanisms (e.g., fatigue and wear) and their impacts on modeling Common Cause Failures (CCFs) in PRA frameworks.”

In 2010, Mohaghegh founded Soteria Consultants, a risk management consulting enterprise that supports proactive decisions involving complex systems. One of her current projects, funded by the South Texas Project Nuclear Operating Company (STPNOC), focuses on the risk-informed resolution of the Nuclear Regulatory Commission’s Generic Safety Issue 191 (GSI-191).

Earlier this year, the International Association of Probabilistic Safety Assessment and Management (IAPSAM) chose Mohaghegh for the George Apostolakis Fellowship, presented to an “early career” professional active in the field of Risk Assessment.

Mohaghegh will establish a Socio-Technical Risk Analysis (SoTeRiA) research lab in NPRE and, with her students, will continue this line of research. “I welcome students who are passionate about multidisciplinary research. I look forward to collaborating with faculty in NPRE, with other departments at Illinois, and with other universities. NPRE has been a most welcoming nuclear engineering department regarding multidisciplinary research,” says Mohaghegh who published a book, Socio-Technical Risk Analysis, and has written many journal and conference papers on the subject.

She would like to design courses in three different categories: “(1) Methods of Probabilistic Risk Assessment and Management of Complex Systems (e.g., accident sequence precursors, uncertainty analysis, Bayesian analysis, risk-informed decision making) (2) Hardware Reliability (e.g., system and component reliability, probabilistic physics-of-failure), and (3) Human Reliability and Organizational Safety (e.g., human error modeling, management & organizational factors, and safety culture).”

Mohaghegh’s hope is to promote risk/reliability analysis as an area of concentration in NPRE. “In addition to enhancing the current curriculum for graduate students in general, a selective set of these courses can create a potential for risk analysis certificates for those students in this department or other engineering departments who want to join the industry as risk or reliability analysts.” says Mohaghegh, who serves as the Technical Program Chair for the 2013 American Nuclear Society Risk Management Topical Meeting. She is a member of the Society for Risk Analysis, American Nuclear Society, Society of Women Engineers, and American Society of Mechanical Engineers.