After more than a two-year hiatus, the U.S. Nuclear Regulatory Commission is once again renewing licenses for aging nuclear power plants.

The independent federal agency gave a 20-year license renewal on Oct. 20 to Limerick Generating Station Units 1 and 2 near Philadelphia and is now reviewing renewal applications for 17 additional reactors, including Indian Point Unit 2 that’s located on the Hudson River about 24 miles north of New York City.

The NRC, which licenses commercial nuclear power plants for a period of 40 years, has granted 20-year extensions to 74 of the 100 operating reactors in the United States, many of which were nearing the end of their licenses. No reactor has yet sought a second license extension. These  commercial