Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of USEC (NYSE: USU) fell 10% today after the tsunami and earthquakes in Japan affected two reactors there.

So what: Three reactors in Japan are experiencing problems, and with recent explosions and the possibility of more issues, it isn't surprising to see nuclear stocks down today. USEC CEO John Welch released a statement today that said in part "USEC stands ready to assist."

Now what: If we take a step back from the human impact of these nuclear plants and put our investor hats on again, I just don't see this dip as a buying opportunity. Operations at USEC may not be dramatically affected, but a cloud will hang over any stock with ties to the nuclear industry for the foreseeable future. I'm selling today's move and will wait for calmer days in Japan before looking for discounts in nuclear stocks.

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