Dr. Nathan Siu was appointed to the U.S. Nuclear Waste Technical Review Board by President Joseph Biden on October 25, 2022. He served as Chair of the Board through September 16, 2024.
Nathan Siu is an independent risk assessment consultant. He retired from the U.S. Nuclear Regulatory Commission (NRC)in 2021, where he was a Senior Technical Adviser for Probabilistic Risk Assessment (PRA) in NRC's Office of Nuclear Regulatory Research. His responsibilities included advising management on PRA issues; developing PRA research programs to address key issues; providing PRA-related advice and support to technical staff; supporting PRA-related cooperative research activities with U.S. and international organizations; and supporting technology transfer to other technical communities. Prior to joining NRC in 1997, he was an Engineering Fellow at the Idaho National Engineering Laboratory, an Associate Professor of Nuclear Engineering at the Massachusetts Institute of Technology, and an Associate Consultant at Picard, Lowe, and Garrick, Inc.
Dr. Siu is internationally recognized for his expertise in risk assessment for nuclear facilities. He is a past Chair of the Working Group on Risk Assessment for the Organization for Economic Cooperation ad Development's Nuclear Energy Agency and served as a consultant on an International Atomic Energy Agency project on advanced PRA methods. He has chaired the NRC's Technical Advisory Group on NRC Level 3 PRA and served as a Chair of the NRC's Risk Management Team. He is a past member of the Editorial Board of Reliability Engineering and System Safety and the Board of Directors for the International Association for Probabilistic Safety Assessment and Management and has served in technical leadership positions in numerous technical meetings and conferences. Dr. Siu is a Fellow of the American Nuclear Society and has authored or co-authored over 180 technical papers and reports focusing on risk assessment methods and applications but also addressing such topics as risk metrics, risk communication, enterprise risk management, and risk-related knowledge engineering.