When a train arrives on time or when a power grid stays online during a storm, most people see reliability. Italian scientist Enrico Zio, however, sees a carefully balanced equation of risk, resilience and human judgment.

As a leading engineer and researcher in the safety and reliability of complex systems, Zio has spent over three decades asking deceptively simple questions: How do things fail, and how can we prevent them from failing? And if they fail, how can we minimize the damage and recover from the failure? His work focuses on the intersection of system engineering, probabilistic modeling, AI and human behaviour—especially concerning systems where failure is not an option, from nuclear reactors and aerospace missions, to smart cities and interdependent critical infrastructures.

In a recent interview with Science and Technology Daily (S&T Daily), he shared insights from his decades of research, his deep collaboration with Chinese institutions, and his vision for the future of science in an increasingly interconnected world.

Making sense of risk

At its core, Zio’s work is about understanding failure, not to dwell on it, but to prevent it and manage it.“This means trying to characterize the wrong behavior of a complex system,” he explained.

A complex system is made up of physical parts, digital components and human beings, all working together to produce and deliver services such as transportation, energy or communication. But when one piece fails, the entire system can be disrupted, he noted.

“Studying risk and resilience means looking inside the system, its components, their connections, the physics of the mechanisms of their failure, the way they are operated and maintained,” he said.“What can go wrong? What are the consequences? Is there danger to people or the environment? To the system itself? How much? And how often might these failures occur?”

The answers to these questions guide real-world decisions on design, operation and maintenance: for example, how to maintain the infrastructure, how to respond to emergencies in case of failure, and how to recover quickly to be resilient.

“The research benefits coming from searching answers to these questions, solutions to these problems are very tangible,” Zio emphasized. For example, when he looks at autonomous cars, he sees beautiful technological advancements, but his job is to ensure there’s no risk of accidents caused by system failures, errors in the digital communication, or inaccurate output from the AI used. In all safety-critical contexts, like space exploration or nuclear energy, where public safety and national investment are at stake, rigorous risk analysis is essential.

Witness to China's sci-tech development

Having visited China regularly for over 20 years, Zio has witnessed the country evolve from a growing technological player into a global leader.

When asked to describe China’s scientific advancement in just three words, he didn’t hesitate.“[Firstly], amazing,” he said,“because I’ve seen the change in the efficiency and effectiveness of managing such a complex system, a nation with the largest population, huge distances and immense demands of products and services, of wellbeing for all.” From high-speed rail networks running with near-perfect punctuality, to breakthroughs in electric and autonomous vehicles, to effective realization of nuclear power plants, Zio finds China’s ability to execute large-scale technological projects nothing short of extraordinary.

“[Secondly] stimulating,” he continued,“because the solutions China has implemented in such a complex environment challenge us in the West to reconsider our own systems and solutions. If China can solve these large-scale problems, why can’t we?”

“[Thirdly] reassuring,” he said, adding that,“China’s successful models in the sci-tech field offer hope for tackling global challenges like climate change, energy security and sustainable development.”

'Collaboration is fundamental'

Zio has collaborated extensively with Chinese universities, including Beihang University, where he serves as Advisory Professor; the Harbin Institute of Technology and Harbin Engineering University, where he serves as Guest Professor and Chair Professor, respectively. He applauded his Chinese peers for their kindness, respect for collaboration, and depth of knowledge.

Over the years, Professor Zio has made remarkable contributions to these Chinese universities' research and talent cultivation, mentoring more than 10 joint PhD students and guiding them in research projects, academic writing, and methodological development in Milan. His insights and participation have provided significant academic and technical support to these universities' numerous research programs.

During the International Month 2025 held by the China Association for Science and Technology, he participated in high-level discussions with Chinese scientists, reinforcing the importance of international cooperation.“Collaboration is fundamental,” Zio said.“The world has too many complex problems for any one country to solve [all the challenges] alone. We need to share perspectives, experiences and knowledge.”

He pointed to China’s progress in nuclear energy as a prime example.“I’ve been lucky to witness China’s journey in nuclear power—not just building plants, but developing safer, more efficient future designs. This isn’t just about technology. It’s about skill education, safety culture, regulation, and long-term planning.” Zio added that China is achieving all this at the speed of light.

Mentoring the future

Reflecting on his own journey from studying nuclear engineering at Politecnico di Milano, UCLA and MIT, to pioneering work in AI and risk assessment, first under the guidance of his supervisors and then with the contribution of his collaborators and students, Zio offered heartfelt advice to young scientists and engineers: Focus on the work, not the rewards (these come as a consequence). And love what you do.

“Young researchers’ goal should be to do the work well, to be passionate, motivated, and deeply engaged in solving real difficult problems,” Zio said.

He admitted that research is a rollercoaster that is,“terribly frustrating and terribly exciting,” but emphasized that the breakthroughs, when they come, are worth the struggle.

When asked about the most rewarding aspect of his career, Zio spoke of his students.“The development of young researchers who have become great scientists—that gives me the most satisfaction.”

Finally, his thoughts on AI indicate that he sees it as a powerful tool but it needs to be treated with caution against relying on it to replace curiosity and critical thinking.“If AI finds the solution itself, it means the problem was easy. [And it was too easy], why [are you] doing research?” he asked. Certainly, points to ponder.