It's been a slow news day at the Fukushima meltdown site, and so nuke disaster chasers have been splitting their screens between Japan and Nebraska, where two nuclear plants on the flooded Missouri River have declared low-level emergencies. One of the plants, Fort Calhoun, 19 miles outside of Omaha, is completely surrounded by water. The river is now actually higher than the ground on which the plant sits. Apparently a six- or eight-foot-high temporary rubber wall is keeping the muddy river water out of the plant basement.

Company officials swear that the building is watertight, and that even if the rubber wall gives way or is topped, there'll be no radiation leak. The plant was shut down for a refueling in April and didn't fire back up because it was known that the floods were coming. The facility's crowded spent fuel pool, however, remains a major hazard.

The scariest thing we've read about the Fort Calhoun situation so far is that the plant is now accessible only by water, and it's expected to remain that way for quite some time. Flooding on the Missouri is expected to continue for another couple of months. If something nasty does happen, getting a proper emergency response to the reactor site could be quite a challenge. Just to give some perspective, nearby Interstate 29 is under around 10 feet of water at the moment.

Down river a ways, the Cooper reactor is continuing to operate at 100% power, even though the flood waters were at last report just 18 inches below the level at which the plant would be required by nuclear regulators to shut down entirely. The operator, a public power district, says it intends to keep running the reactor until that level is reached.

Both plants would be in deep kim chee if a dam or levee upstream should break. The reactors may be able to handle a few more feet of gradually rising river, but a wall of water several stories high could lead to Fukushima-like problems. As long as the plants have electricity to run cooling pumps, they'll probably be fine, but it's not inconceivable that a big enough flood surge could cause a blackout and thwart the backups for an extended period. That would not be good.

In other American nuke news, it's becoming increasingly clear what many critics have suspected for a long time: Nuclear power plants routinely dump radioactive liquid into groundwater and nearby bodies of water. In other words, they're killing us slowly. When something bad happens, they compare the latest dose to "background" radiation, but what they don't say, and people need to realize, is that the "background" consists in part of nuclear waste that the nuclear weapons-and-power industry has itself dumped into the environment over the past 70 years. And no level of exposure to ionizing radiation is without health risk.