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 nuclear services specialist EnergySolutions (NYSE: ES) plummeted more than 15% on Thursday after its quarterly results and full-year guidance failed to meet Wall Street expectations.

So what: According to the company, business activity was in line with expectations, but a change in accounting treatment for its Zion decommissioning project led to a fourth-quarter loss of $22 million, or $0.25 per share. Even when you exclude that one-time item, however, EnergySolutions' adjusted income of $10.5 million, or $0.12 per share, came in well below the average analyst estimate of $0.19 per share.

Now what: I'd look into this near-20% plunge as a possible long-term entry point. While EnergySolutions' full-year EBITDA guidance of $130 million to $140 million also disappointed Wall Street, the company seems to be building a solid foundation with the expected ramp-up of Zion, as well as a generally more focused growth strategy. The shares had been recovering nicely from its recent nuclear-fear-induced beating, but today's plunge might be giving investors yet another chance to pounce.

Interested in more info on EnergySolutions? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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