When the Fukashima Dai-Ichi nuclear plant started its slow meltdown a little over a month ago, it took a while for the investment community to figure out exactly what it meant for the future of nuclear power. Nuclear-related stocks have been pummeled on fears that the industry has reached its half-life, but we haven't really known what the real future of nuclear power would be.

But last week's news that NRG (NYSE: NRG) was writing off its investment in a nuclear plant development may tell you everything you need to know about where nuclear power is headed. The South Texas Nuclear Development Project (STP 3&4), which was suspended last month, is leading NRG to take a $481 million pre-tax hit in the first quarter to write-off assets related to the development.

The potential development isn't the only one in the U.S., with the Watts Bar Nuclear Plant's Unit 2 set to come online next year. But NRG's writedown may tell us everything we need to know about the future of nuclear for companies in the sector, like General Electric (NYSE: GE), Toshiba, and Siemens (NYSE: SI). Siemens is at the very least uneasy about its nuclear ambitions, and it might be fighting for a smaller pie even if it decides to stay in the game.

I have to agree with fellow Fool David Lee Smith that opportunities are arising in nuclear if you stick with uranium suppliers. New plants may be in question, but the nuclear plants that are already operating aren't going to be shutting down any time soon. Exelon (NYSE: EXC), Cameco (NYSE: CCJ), Uranium Energy (NYSE: UEC), and Uranerz Energy (NYSE: URZ) will have demand for their services for years to come. Demand may not be as strong as they hoped, but unlike the builders of nuclear plants, their entire business hasn't come into question yet.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.