What if high-level radioactive waste had been aboard?! -- Arizona train derailment and fire described as 'a scene from hell'

Arizona train derailment and fire described as 'a scene from hell'

as reported by CNN.

Depending on the temperature and duration of a fire, high-level radioactive waste shipping containers could be breached. The design criteria for such containers is for a 1,475 degree Fahrenheit fire, burning for only 30 minutes. Many real world fires burn hotter, and longer, than that. A breach of a container, and the release of even a small fraction of the volatile contents of a cask (such as Cesium-137), would cause a disastrous or even catastrophic release of hazardous radioactivity into the environment.

And if a train bridge collapses above water, the underwater submersion of a high-level radioactive waste shipping container could cause a breach, depending on the depth of the water, and the duration of the submersion. As a Public Citizen backgrounder documents, design criteria for shipping containers only account for a 3 foot submersion, for a damaged container; the design criteria for undamaged casks is for a depth of 656 feet, for one hour. But many bodies of surface water are deeper than 3 feet. And the containers weighing as much as 180 tons, or more, these days, it would require a special crane to lift them -- something that would take much longer than an hour to bring in, set up, and activate. A breach and release could cause catastrophic hazardous radioactive contamination of drinkinging water supplies, fisheries, etc.

In addition, infiltrating water could spark an inadvertent nuclear chain reaction, if a critical mass of fissile material (U-235, Pu-239) forms inside the irradiated nuclear fuel container. This would potentially make emergency response a suicide mission, given the fatal doses of gamma and neutron radiation emitted by a chain reaction. But doing nothing could mean catastrophic releases of hazardous radioactivity into the surface water. See this backgrounder, for more information about such risks.