Explosion at Damaged Japanese Nuclear Power Plant [Updated]

A damaged nuclear power plant in northern Japan was rocked by a massive explosion on Saturday, destroying the roof and releasing an unknown amount of radiation. Officials widened the evacuation zone to 12 miles around the Fukushima Daiichi Nuclear Power Station, where backup diesel generators failed in the wake of Friday’s earthquake.

Officials said that the steel container that holds the power plant’s nuclear fuel was still intact, but Ryohei Shiomi of Japan’s nuclear safety commission told the AP that a meltdown is possible.

Here’s a video of the explosion, via the English-language channel Russia Today:

Nuclear fuel rods require a constant stream of water to avoid overheating. The quake knocked out electricity that fed the water pumps, and backup diesel generators failed to come online, forcing the plant to rely on battery-powered pumps that were only capable of running on their own for several hours.

The lack of power for emergency cooling system had been steadily increasing pressure inside one of the plant’s reactors, which could have led to the explosion. The Times reported that radiation levels in the plant’s control room were 1,000 times above normal.

U.S. Secretary of State Hillary Clinton said on Friday that U.S. armed forces were bringing “coolant” to the damaged reactor. Technology writer Robert Cringely, who worked as a government investigator on the Three Mile Island accident some 32 years ago, speculated that coolant could be sodium polyborate, which would shut down any nuclear fission reactions but would also render the multi-billion plant inoperable for good. “Sodium polyborate, by the way, is something you might use around the house, since it is the active ingredient in most flea and tick treatments,” Cringely said on his blog.

The BBC’s Richard Black said “the detection of caesium isotopes outside the power station buildings could imply that the core has been exposed to the air … Although Japan has a long and largely successful nuclear power programme, officials have been less than honest about some incidents in the past, meaning that official reassurances are unlikely to convince everyone this time round.”

In addition to a series of powerful aftershocks, the country’s meteorological agency is reporting separate earthquake in the Nagano and Niigata prefectures. The U.S. Geological Survey says this latest event is a 6.2-magnitude quake. Nagano police have not yet had any reports of major damage. In the Niigata prefecture, police said the earthquake caused landslides and avalanches, but again no casualties. According to The Wall Street Journal some Japanese citizens are a little skeptical of government reporting of casualty statistics, considering that Kyoto was “extremely slow to release information in the wake of the Kobe earthquake in 1995, when more than 6,000 people were killed.”

The U.S., on other hand, has evaded any major damage from tsunamis. Crescent City in California appeared be hit the hardest, with 35 boats and most docks in the harbor destroyed. It’s the same place that lost eleven residents to a tsunami in 1964. Four people were rescued from the water in Oregon. But Coast Guard helicopters are still searching for a North California man who was taking photographs of the tsunami near the mouth of the Klamath River in Del Norte County and was swept out to sea. For the rest of the day, how about everyone practice safety first?

Explosion Rocks Japan Nuclear Plant After Quake [NYT]
Huge blast at Japan nuclear power plant [BBC]
Japan says meltdown possible at nuclear plan [AP via Guardian]
Flea powder may be saving lives in Japan [I, Cringely]
Tsunami sweeps 5 to sea, rips out Calif. docks [AP]
Related: Biggest-Ever Japanese Earthquake Prompts Tsunami Warnings Throughout Pacific

This post has been updated with additional information.

Explosion at Damaged Japanese Nuclear Power Plant [Updated]