China’s Xinhua news agency is claiming (via AllVoices.com) that radioactive cesium has been detected in the atmosphere from the Fukushima I plant. However, the AllVoices.com post is pretty garbled, and leads one to believe there could be a complete meltdown (which is very unlikely). A partial meltdown (which seems, pretty obviously, like it’s already happened, though no one’s admitting it) is bad enough.
The BBC confirms that cesium (aka “caesium”) and iodine has been detected near the number 1 reactor, though it doesn’t say whether it was within the structure or not. The concrete building has been destroyed by the explosion, but the steel containment vessel is said to be intact.
However, the AllVoices post is incoherent enough that I’m not sure whether to trust the Chinese cesium-in-the-atmosphere report. Fukushima uses mixed-oxide (MOX) fuel. Civilian nuclear plants tend to use one or several of three substances for fuel — uranium, plutonium, or cesium thorium.*
Mixed-oxide fuel is a mix of oxides of more than one fissile material, but the term usually refers to a mix of uranium and plutonium. Plutonium is the most toxic substance known, even apart from its radiation. Decay of the fuel inside the reactor produces americium, thorium and curium, plus lots of cesium. Because of the nature of nuclear plants, it’s not like most waste products are put out of an exhaust pipe; I would think the generated cesium is integral to the core.
If that’s true, it seems possible (though I don’t know for sure) that a cesium release would indicate that part of the core has been exposed. Just a guess. However, the Wikipedia article on cesium says that it’s part of nuclear plant “emissions,” which doesn’t sound like it’s a direct decay product within the fuel rods. That’s somewhat comforting.
As of this writing (11:26 am Pacific Time), Al Jazeera leads its English site with the above story about the Fukushima plant, but CNN does not. What CNN does do is show a story title on the front page: “Pump system caused nuclear blast.” That’s now at least the fourth front-page teaser I’ve seen on CNN calling it a “nuclear blast.”
This was not a nuclear blast. It was a blast in a nuclear plant. A “nuclear blast” is a chain reaction caused by weapons-grade fissionable material reaching critical mass rapidly enough to cause a sustained explosive chain reaction instead of merely a chain reaction (all nuclear plants reach criticality, and sustain chain reactions). On the other hand, a blast in a nuclear plant could be a lot of different things. None of them good; none of them good at all. But none of them a “Nuclear blast.”
Does the distinction not seem important? Well, it’s damned important, particularly in Japan. It’s the difference is between Three Mile Island and Hiroshima, and I’d appreciate it if CNN would get it straight. Failure to make that distinction is unfair to the potential victims of what is happening.
In this case, what the explosion is reported to indicate was the failure of a pumping system, which “buckled the walls of a concrete building that surrounded one of the plant’s nuclear reactors, but did not damage the reactor itself,” says CNN. At least three workers have gotten radiation exposure. Here’s the really scary part from CNN:
On Saturday night, three patients at a hospital tested positive for radiation exposure, according to the Japanese public broadcasting station NHK, citing a statement from Fukushima Prefecture.
The three were randomly selected from a group of 90 hospital workers and patients who were already at the medical facility — about three kilometers from the Daiichi plant — before Friday’s massive quake. The patients were outside of the hospital awaiting evacuation at the time of the explosion.
However, Al Jazeera’s report says “However, local media reported that three workers have suffered radiation exposure.” That sounds like those are three different people, and if there was a release of radiation, a lot more workers than three will have suffered radiation exposure once the info goes out. But if random members of the populace are showing radiation exposure, that obviously isn’t good.
More from CNN:
Japanese authorities appeared to be preparing for the possibility of a nuclear release. Japan public broadcaster NHK reported the country’s defense ministry had sent a unit that specializes in dealing with radioactive contamination to a command post near one of the stricken plants.
The government was also preparing to distribute iodine tablets to residents, the IAEA said. Iodine is commonly prescribed to help prevent the thyroid gland from taking in too much radioactivity, according to the U.S. Environmental Protection Agency website.
Iodine tablets are designed to prevent people from taking in radioactive iodine from the environment; iodine takes on radiation in the case of exposure, so in the absence of iodine tablets, radioactive iodine can travel to the thyroid and cause cancer.
*UPDATED 8:51PM Saturday, Pacific Time: I wrote earlier today that the three possible fuels for nuclear reactors were uranium, plutonium, and cesium — MOX being a mixture of oxides of plutonium and uranium. I meant, of course (of course!!) thorium, not cesium. Cesium is a by-product of reactors — one of many; thorium is another — and an indicator that partially consumed nuclear fuel has been exposed. Thorium is a potential alternative fuel to uranium, plutonium, and MOX, but it is not in wide use. I’m not sure whether to be pleased with myself that I noticed that flub without anyone reminding me, or disturbed that I made it in the first place. Whatever. Thorium. Thorium. Thorium. KThxbai.