The three most feared words in the lexicon of a nuclear scientist is "breach of containment," i.e. an uncontrolled release of radiation into the environment. It appears that we may be seeing this dreaded event unfolding in Japan.
Two workers got radiation burns when exposed to radioactive water 10,000 times the normal level. The only way in which water could have been so contaminated is via exposure to uranium fuel, either in the core or in the spent fuel pond. A source told the NY Times that there is a huge vertical crack in the vessel of Unit 3. It is below the water level, so radiation is spreading directly into the water.
This represents a dangerous escalation of the crisis. Even at Three Mile Island, where 90% of the core suffered damage, the steel vessel surrounding the core was not breached. In a best case scenario, the crack will not widen, and workers can use freshwater (not corrosive salt water) to keep the fuel rods cool. This may stabilize the accident.
However, the worst case scenario is quite different. If radiation levels continue to rise, then at some point the workers may have to evacuate. (A secondary earthquake or pipe break may also aggravate the situation). If the workers abandon the ship, it means that cooling water (which is being shot into the reactors by fire hose) will begin to fall, exposing the rods, and eventually creating 3 simultaneous meltdowns. Then perhaps a steam or hydrogen gas explosion will completely rupture the containment. This will create a nightmare beyond Chernobyl.
In the meantime, I have suggested on TV that the leadership of the crisis management be replaced. The utility should be kept on as a consultant, but a top flight international team of nuclear scientists and engineers should take over, aided by access to the Japanese military. The utility is simply overwhelmed by the crisis. Only the mililtary, guided by an international team of top scientists and engineers, can tame this monster.
More updates to follow - Stay Tuned.