One of Nebraska's two nuclear power plants - Fort Calhoun Station north of Omaha - is surrounded by the Missouri River.
The Fort Calhoun plant is about 75 miles east of Columbus.
The other - Cooper Nuclear Station near Brownville - is close to shutting down because the Missouri River is rising to critical levels and pushing water over levees.
People are understandably nervous. They worry about a nuclear disaster like the one that occurred in Japan after an earthquake and tsunami in March.
And inaccurate information and rumors floating on the Internet are fueling the fear.
For example, there's a report that a Russian nuclear agency has accused President Barack Obama of covering up a nuclear near-meltdown on June 7 at Fort Calhoun.
In fact, said the U.S. Nuclear Regulatory Commission and the Omaha Public Power District, there was a fire in an electrical switchgear room that day, but the spent-fuel pool was in no imminent danger and a fire-suppression system extinguished it quickly.
The plant temporarily lost power to a pump that cools the spent-fuel pool, but power was switched to a backup pump, said OPPD, which runs Fort Calhoun. During the 90-minute interruption, the temperature of the pool increased a few degrees, but the pool was not in danger of boiling, the utility said.
The reactor and spent-fuel pool are in a normal, stable condition and are protected from flooding, OPPD said. The plant was shut down for refueling in April and will remain shut down until floodwaters recede.
Another Internet rumor claims there's a no-fly zone around Fort Calhoun Station because of a radiation leak.
"Rumors about a radiation release at the site - that never happened," said Victor Dricks, spokesman for the NRC Region IV office in Arlington, Texas.
Dricks said a no-fly zone put in place around all U.S. nuclear power plants after Sept. 11, 2001, has been relaxed, but planes are not supposed to fly or loiter near them.
OPPD spokesman Jeff Hanson said air space around Fort Calhoun is restricted by the Federal Aviation Administration to a two-mile radius below 3,500 feet because OPPD was concerned small planes would get tangled in high power lines.
A third rumor concerns a Level 4 emergency at Fort Calhoun Nuclear Station.
Said Dricks: "There isn't a Level 4 emergency at the plant. It is a misnomer."
OPPD declared a notification of an unusual event on June 6 because of expected high river levels, he said, and someone said it was a Level 4 nuclear emergency based on the International Nuclear and Radiological Event Scale. Level 4 means "accident with local consequences." The NRC uses a different system.
Dricks said six NRC employees are working at Fort Calhoun instead of the normal two because of the possibility of flooding.
"Both plants are taking appropriate action to protect vital equipment," Dricks said of Fort Calhoun and Cooper, which is operated by the Nebraska Public Power District.
David Lochbaum, director of the nuclear safety project for the Union of Concerned Scientists, said both plants have had time to prepare for Missouri River flooding. Headquartered in Cambridge, Mass., the group generally is critical of nuclear reactor safety.