The majority of u. s. uranium mines and tailings piles are located in the states; most nuclear power plants are in the states.

southwestern... northeastern

Explanation:

The United States is one of the countries that has one of the most abundant mines of uranium in the world. The majority of the uranium is mined in the southwestern sates, such as Texas, Arizona, Colorado, and Utah. Despite having the majority of the uranium mined in this part of the country, the power plants that use it for production of nuclear energy are not located in close proximity. In fact, most of the power plants are located east of the Mississippi River, with the highest density of power plants being in the northeastern states. In the western part of the country there is only four power plants.