Shares of Centrus Energy (LEU -3.38%), a specialist in enriching uranium for use as fuel in nuclear reactors, tumbled 4.7% through 12:50 p.m. ET Wednesday after one of its partners announced some disconcerting news.

Nuclear power plant start-up Oklo, which had previously signed a memorandum of understanding agreeing to accept high-assay low-enriched uranium (HALEU) supplies from Centrus once its reactors are running, is now teaming up with two other nuclear start-ups. Privately held Hexium and privately held and Bill Gates backed TerraPower, will, along with Oklo, "leverage advanced laser enrichment technology to build a scalable U.S. nuclear fuel supply for advanced reactors."

Image source: Getty Images.

Et tu, Oklo?

Oklo's desire to team up with a heavyweight like TerraPower is understandable. For a cash-strapped nuclear start-up, it may pay to be on the same team as a company with a backer as well heeled as Gates. Also, Hexium's new technology for enriching uranium may hold advantages over Centrus'.

That being said, Oklo's joining a new team does have the potential to leave Centrus in the lurch. We don't know at this time whether Hexium's tech will pan out nor, if it does, whether Oklo will still proceed to buy HALEU uranium from Centrus as well as from Hexium.

But if it doesn't then this could mean Centrus has just lost a customer that it was counting on keeping.

Is Centrus stock now a sell?

Don't be too quick to pull the sell trigger on Centrus, though. Just because Oklo thinks Hexium will work out as a partner doesn't mean it's right. Centrus is at least a known quantity and an established enriching company already.

It's also profitable, earning more than $100 million over the last 12 months, generating positive free cash flow, free of net debt -- and potentially, a buy.