You could think of such a power plant as something like a thermonuclear internal combustion engine with laser spark plugs. Actually I wonder if giant pistons similar to the huge diesels built by Wartsila and others for container ships could work. Put some water in there with the fuel pellet and the water would be flash vaporized by the fusion yield. You'd be talking about a pretty massive engine bore, probably much larger than those monster diesels. Might be worth doing for sheer awesomeness. :)
I don't know the numbers but my guess is that lasers would have to be dramatically more efficient than they are today for this to be a practical and economical way of generating power.