His doctoral research focused on studies in nuclear reactor dynamics, specifically on the accuracy of point kinetics and the effect of delayed neutrons on the spectrum of the group diffusion operator.

[2] Apostolakis began his academic career at the University of California, Los Angeles in 1974 and later moved to the Massachusetts Institute of Technology in 1995, where he became a professor in the Department of Nuclear Science and Engineering.

He also played a role in the NRC's response to the Fukushima Daiichi nuclear disaster, advocating for enhanced safety measures and risk assessments.

[1] After completing his term at the NRC, Apostolakis continued to work in the field of risk sciences through his involvement with various organizations and academic institutions.

[2] Apostolakis's work has impacted the field of nuclear engineering and risk assessment, contributing to the development of modern safety protocols and regulatory practices.