1.   Company officials said installing liners in the steam tubes made the most sense.

2.   Cracks in steam generator tubes have been a chronic problem for the industry, requiring virtually every pressurized water reactor to plug some of the tubes to prevent leakage.

3.   Cracking steam tubes also represent a major cost to the industry, forcing reactors to shut down for repairs or even permanently reduce power output.

4.   Somebody with a steam tube the size of a railroad tunnel and a couple of well-trained elephants might actually have done it.

5.   The robots were dropped into steam generator tubes.

6.   The robots, which are several inches long and resemble thin cylinders, were dropped into steam generator tubes.