Nuclear stocks are trading lower across the board on Monday after regulators rejected Talen Energy Corp's (NASDAQ:TLN) plans to increase power for an Amazon.com Inc (NASDAQ:AMZN) data center.

What Happened: The Federal Energy Regulatory Commission (FERC) on Friday rejected Talen Energy's request to increase how much power its Susquehanna nuclear plant in Pennsylvania can provide to Amazon Web Services.

According to a CNBC report, Talen Energy sold a data center campus to Amazon in March for $650 million. The company had filed a request to increase the power dispatched to the facility from 300 megawatts to 480 megawatts, but FERC shot it down, saying the arrangement could have "huge ramifications" on grid reliability and consumer costs.

Talen issued a statement in response to the order rejecting its amended plans, saying it believes FERC "erred" in its decision. The company noted that it's evaluating its options with a focus on commercial solutions.

"We believe this ISA amendment is just and reasonable and in the best interest of consumers. FERC's decision will have a chilling effect on economic development in states such as Pennsylvania, Ohio, and New Jersey," the company said in the statement.

Talen noted that the existing agreement allows for 300 MW of co-located load at Susquehanna. Despite the rejected amendment, Talen said it can still proceed with development of the first phases of the Amazon Web Services data center campus using the 300 MW while it continues to pursue approval of an amended agreement.

Several nuclear stocks are falling Monday after rallying over the past month. Constellation Energy Corp (NASDAQ:CEG) and Vistra Corp (NYSE:VST) were down 10.5% and 2.2%, respectively, in sympathy with Talen.

Oklo Inc (NYSE:OKLO), which is chaired by OpenAI's Sam Altman, has been one of the most popular nuclear plays in recent weeks. It was down 6.65% at $20.22 at the time of writing.

Other small modular reactor (SMR) companies like NuScale Power Corp (NYSE:SMR) and Nano Nuclear Energy Inc (NASDAQ:NNE), were also trading lower, down 2.5% and 10.2%, respectively.

Nuclear fuel names have also seen increased attention in recent weeks. Shares of uranium fuel producer Cameco Corp (NYSE:CCJ) were down more than 2% at the time of writing. Shares of Lightbridge Corp (NASDAQ:LTBR), a nuclear fuel technology company, were down 1.93% at last check.

Shares of ASP Isotopes Inc (NASDAQ:ASPI), which signed a deal with Bill Gates-backed TerraPower last week and has seen increased attention across social platforms in recent weeks, were down about 14% at the time of writing.

The VanEck Uranium And Nuclear ETF (NYSE:NLR) was down 3.22% and the Global X Uranium ETF (NYSE:URA) was down 2.37% in afternoon trading Monday.

Despite Monday's pullback, nuclear stocks are still up significantly over the past month driven by an increased focus on nuclear from hyperscalers aiming to keep up with the rising energy demands of data centers related to the AI boom.

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