Final answer:
The main drawback of nuclear energy is the production and disposal of long-lived radioactive waste, which presents significant environmental and health challenges.
Step-by-step explanation:
One major drawback with nuclear energy lies in the problematic radioactive waste it produces. Nuclear fission, which powers nuclear reactors, results in the creation of highly radioactive materials with long half-lives, such as uranium-236. These substances pose significant environmental challenges due to their long-term radioactivity, raising concerns about human health, safe storage, and contamination prevention. Safe disposal solutions include storage in geologically stable locations like salt mines and mountains, but the persistent threat and need for long-term management remain central issues.