Fukushima 1: third explosion takes place, officials fear damage to suppression pool

A third explosion occurred at the stricken Fukushima 1 nuclear power plant at around 06:20 local time today. The explosion took place at the 2nd reactor and initial reports have suggested that there may have been some damage to the suppression pool of the containment vessel, which if true, would mean a higher risk of a significant release of radioactive material. According to the IAEA, a fire at a spent fuel storage pond near the plant’s fourth reactor has been put out. The fire had been causing radioactivity to be released directly into the atmosphere. Currently only around 50 workers remain on site with the rest of the plant’s 800 strong workforce having been evacuated. TEPCO officials believe that all three of the reactors suffering from cooling failures may have experienced partial meltdowns. A leak at unit 3 is making it difficult to keep the reactor core covered with seawater, according to Dr Michio Kaku, a physicist, with reports that up to 90% of the core may have been uncovered.

This morning, radiation levels of 400milliSieverts an hour were recorded at the site’s third reactor. To put this in perspective, an accumulative exposure of 1000milliSeverts is estimated to result in fatal cancer many years later in 5% of exposed individuals. This morning, the Japan Times has reported that radiation in Tokyo is 20 times above normal, but is still posing no risk to human health.

TEPCO’s website is reporting that all four reactors have stable water levels, with offsite power available, no refrigerant leaks in the reactor containment vessels and workers are maintaining average water temperatures of 100˚C in the pressure restraints.