In which situation is external exposure to depleted uranium a major concern?

External exposure to depleted uranium (DU) is a significant concern when near DU rounds due to the physical and radiological properties of the material. Depleted uranium is denser than lead, which makes it effective in armor-piercing applications. When munitions containing DU are used, fragments and dust can be released into the environment. Proximity to these rounds increases the likelihood of receiving external radiation and also poses a risk of contamination through inhalation or ingestion if fine particles are disturbed.

While situations such as aircraft operation, maintenance of nuclear equipment, and confined spaces can involve radiation exposure, the specific concern with DU primarily stems from the nature of weaponized DU munitions. The risk from DU rounds is heightened in environments where these materials are present and can lead to meaningful external dose rates. This emphasizes the need for effective protective measures and monitoring in military and civilian sites where DU munitions are present.