Nuclear-power stocks slumped on Monday after US regulators barred a plant from supplying extra power to an Amazon data center. The Federal Energy Regulatory Commission rejected the deal between Amazon and Talen Energy late last week.

The Federal Energy Regulatory Commission (FERC) rejected an effort Friday to allow an Amazon data center to tap into additional power from a nearby Pennsylvania nuclear plant. The decision could throw a wrench in efforts by large technology companies to secure so-called “behind the meter” power from nuclear plants as they seek to meet

U.S. energy regulators rejected an amended interconnection agreement for an Amazon data center connected directly to a nuclear power plant in Pennsylvania, a filing showed on Friday.