The research problem was an examination of the vulnerability of U.S. nuclear power plants to unmanned aerial system attacks. The purpose of this study was to examine the vulnerability of U.S. nuclear power plants against attack by UAS via the perceptions and experiences of twenty current and former managers, scientists, and contractors employed by the federal government and nuclear industry. The qualitative phenomenological research methodology was chosen because it was well-matched to collecting information regarding one's attitudes, the ability to examine complexities, gather an abundance of data, and identify patterns. The theoretical framework examined was that of national security. Themes identified were (1) the threat of UAS attack against U.S. nuclear power plants was real, and a present-day one; (2) there is an intentional effort for the secrecy of UAS incidents by the Nuclear Regulatory Commission; (3) it was imperative to understand what the goal of the attack would be, i.e., soft facility targets would be likely targeted and damaged by bad actors and damaged while hardened ones would not. Finding security vulnerabilities and immediately closing those security gaps must be done per the theory of national security. Per the Nuclear Regulatory Commission data, there have been 57 UAS incursions over 24 U.S. nuclear power plants in the past five years. Nuclear power plants as a vital component of the nation’s sixteen critical infrastructure sectors are vulnerable, and it is highly likely that all other sectors with fixed sites and well-advertised locations are equally vulnerable to attack by UAS and will remain so until Congress acts.