Re:Crash Testing (Score 1)

...Fire and multiple collisions, for example.

The engineers thought the same thing as you did, judging by the testing criteria that they developed:

(from the Nuclear Energy Institute's website)

Before approval, containers must meet rigorous engineering and safety criteria and be able to pass a series of hypothetical accident conditions that create forces greater than the containers would experience in actual accidents. The same container must, in sequence, undergo (1) a 30-foot free fall onto an unyielding surface, (2) a 40-inch fall onto a steel rod six inches in diameter, (3) a 30-minute exposure to fire at 1,475 degrees Fahrenheit that engulfs the entire container, and (4) submergence under three feet of water for eight hours. Also, by a separate test, containers are submerged under 50 feet of water for eight hours.