Another danger

It’s a little surprising to read in the New York Times that it’s not only the Japanese reactors which are the source of danger, but the cooling pools around them too:

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.

By late Tuesday, the water meant to cool spent fuel rods in the No. 4 reactor was boiling, Japan’s nuclear watchdog said. If the water evaporates and the rods run dry, they could overheat and catch fire, potentially spreading radioactive materials in dangerous clouds. …

The pools are a worry at the stricken reactors at the Fukushima Daiichi plant because at least two of the reactors 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 do 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.”