By William J. Broad and Hiroko Tabuchi, New York Times, March 14, 2011
Even as workers race to prevent the radioactive cores of the damaged nuclear reactors in Japan from melting down, concerns are growing that nearby pools holding spent fuel rods could pose an even greater danger.
The pools, which sit on the top level of the reactor buildings and keep spent fuel submerged in water, have lost their cooling systems and the Japanese have been unable to take emergency steps because of the multiplying crises.
Experts now fear that the pool containing those rods from the fourth reactor has run dry, allowing the rods to overheat and catch fire. That could spread radioactive materials far and wide in dangerous clouds.
The pools are a worry at the stricken reactors at the Fukushima Daiichi plant because at least two of the three have lost their roofs in explosions, exposing the spent fuel pools to the atmosphere. By contrast, reactors have strong containment vessels that stand a better chance of bottling up radiation from a meltdown of the fuel in the reactor core.
If any of the spent fuel rods in the pools did indeed catch fire, nuclear experts say, the high heat would loft the radiation in clouds that would spread the radioactivity.
“It’s worse than a meltdown,” said David A. Lochbaum, a nuclear engineer at the Union of Concerned Scientists who worked as an instructor on the kinds of General Electric reactors used in Japan. “The reactor is inside thick walls, and the spent fuel of Reactors 1 and 3 is out in the open.”
A spokesman for the Japanese company that runs the stricken reactors said in an interview on Monday that the spent fuel at the Fukushima Daiichi and Daini plants had been left uncooled since shortly after the quake.
This story, like so many others, seems to keep jumping out at us from multiple directions and sources, getting worse by the hour. We were, and still are, very concerned about the exposure of the nuclear core reactors, that could meltdown, and now there is a real danger from the spent nuclear rods, sitting in pools on the top of the reactor buildings, also without appropriate cooling, leaving them vulnerable to their own fire and the resulting radioactive comtamination.