Question

which issue poses the greatest long - term challenge in the development of new nuclear power plants?
controlling carbon dioxide emissions
storage of radioactive waste
controlling fission reactions
mining of uranium

Explanation:

Nuclear power plants generate radioactive waste that remains hazardous for thousands of years. Storing it safely is a long - term challenge. Carbon dioxide emissions are not a major issue for nuclear power as it is a low - carbon energy source. Controlling fission reactions is a well - studied and managed aspect in existing plants. Uranium mining, while having environmental impacts, is not as long - term a challenge as radioactive waste storage.

Answer:

storage of radioactive waste