[en] This article provides radiological safety professionals at nuclear power plants with information on the prevention, mitigation, and control of discrete radioactive particles (DRP). In 1990, a health physicist from the ALARA Center at Brookhaven National Laboratory searched the literature, communicated with nine health physicists involved with DRP protection, and visited Southern California Edison Company's San Onofre Nuclear Station, and Arizona Public Service Company's Palo Verde Generating Station to collect data and information on DRPs. A root cause analysis then was performed on how discrete radioactive particles escape from the reactor and coolant system and either irradiate the skin of workers or get inadvertently released off-site. This article organizes the root causes and corrective actions into four categories: discrete radioactive particle production; work environment; worker; and off-site environment. A bibliography of related papers and reports is also included