Operated from 1972 to 1996 and produced 119 billion kilowatt hours of energy
Dry cask storage is a method for safely storing spent nuclear fuel after it has cooled for several years in water pools. Once the fuel rods are no longer producing extreme heat, they are sealed inside massive steel and concrete casks that provide both radiation shielding and passive cooling through natural air circulation—no water is needed. Each cask can weigh over 100 tons and is engineered to resist earthquakes, floods, fire, and even missile strikes. This makes it a robust interim solution until permanent deep geological repositories are available. The casks are expected to last 50–100 years, though the fuel inside remains radioactive for thousands. Dry cask storage reduces reliance on crowded spent fuel pools, provides a secure above-ground option, and buys time for nations to develop long-term disposal strategies. In essence, it’s a durable, self-contained “vault” for nuclear waste
You're thinking abandoned mines. Closed mines are different, and the difference is big. With closed mines the objective is to return the land to its preexisting land use or one that supports something else equally as valuable.
To do that, wastes are managed in a variety of ways. Usually the biggest issues are related to water quality and preventing contamination. Landscapes are re-established and reclaimed. It's not just dust your hands and walk away like it used to be.