Nearly a month after Japan’s nuclear accident, atomic experts and politicians puzzle over a simple question: What danger does the Fukushima Daiichi nuclear plant still pose?
Some areas are still too radioactive for workers to approach. Meanwhile, Japanese reports conflict with those overseas, leading to clouded understanding.
According to the American Nuclear Regulatory Commission, nuclear fuel in the core of a reactor probably leaked from its thick steel pressure vessel. If that is true, fuel leaks will continue and high levels of radioactive releases would vastly complicate containment and cleanup.
But Japanese officials said there was no evidence of a compromised pressure vessel, and they wondered why they read about it in newspapers.
Accordingly, a senior foreign minister accused foreign media of exaggerating dangers.
Who is proved right in the scientific debate has great repercussions for how and when the nuclear crisis might be brought under control, and the potential implications if assumptions prove wrong.
From the start there have been differences, with the American authorities expressing a more pessimistic view than the Japanese.
Accordingly, senior foreign ministers accused foreign media of exaggerating power plant dangers.
Japanese officials believe that water pumped into the reactor to cool it — as opposed to the nuclear fuel itself — might have somehow leaked out. Evidence show that an explosion may have breached the primary containment structure and allowed highly radioactive water into other parts of the plant and the ocean.
For more information about the Fukushima plant, have a look at this NY Times graphic.