EPRI Reactor Theory Practice Exam

The main idea here is how effectively containment and safety systems kept radioactive material from reaching the environment. Even though Three Mile Island involved a partial core meltdown, the design of the plant’s containment meant that most of the fission products stayed inside the closed system. Any release that did occur was extremely small and did not lead to measurable environmental doses or health effects in the surrounding population. Environmental monitoring around the site showed radiation levels near background levels after the event, and regulatory analyses concluded that public exposure remained far below safety limits. So, the best answer is that radiation did not escape into the environment in any meaningful way because the containment did its job.