Nuclear energy stocks are seeing a lot of interest lately with the sector ETF up 65% over the last year. While startups like Oklo and Nano Nuclear are getting attention, the article suggests they are high-risk investments. Both companies are pre-revenue and don't expect to have operational reactors until 2027 or the 2030s. Constellation Energy is highlighted as a more stable alternative. They are the largest nuclear operator in the U.S. and have existing generation capacity. The company recently secured 20-year power deals with Microsoft and Meta, along with a $1 billion government contract. The main argument is that Constellation offers exposure to the nuclear trend with reliable assets and cash flow today, unlike the speculative timeline of the startups.