HOUSTON, May 6 (Reuters) - Nuclear power-plant operators are monitoring forecasts for the rising waters of the Mississippi River and preparing to shut plants later in the month if flooding threatens access to sites or operation of plant safety systems, a regulator said on Friday.
High water is not expected to disrupt operations at nuclear plants located along rivers in the Midwest, but Entergy Corp (ETR.N) officials are preparing for high water at three reactor sites along the Mississippi River from near Vicksburg, Mississippi, to New Orleans, a company spokesman said.
Entergy's 1,268-megawatt Grand Gulf nuclear station in Claiborne County, Mississippi, may be the most vulnerable, officials said, based on government forecasts for the river to reach a high of 57.5 feet (17.5 meters) on May 20, some 14 feet above flood stage.
"We do not expect the plant to shut down if the flooding is not above current projections," said Victor Dricks, a spokesman for the U.S. Nuclear Regulatory Commission's regional office near Dallas.
However, high water could cut off access on the main road to the plant, forcing emergency vehicles to take a longer route, he said.
If river conditions are forecast to worsen, reactors will be shut ahead of time, Dricks said.
Operators are making plans to shut the plants, if necessary, and preparing back-up diesel generators and batteries used to keep emergency cooling systems running in the event of a loss of off-site power.
The Mississippi River is forecast to crest near Entergy's 978-MW River Bend nuclear plant in West Feliciana Parish, Louisiana, on May 23, the National Weather Service says.
Entergy's 1,176-MW Waterford nuclear plant in St. Charles Parish, Louisiana, is expected to complete a month-long refueling outage in the next week or so, before Mississippi River floodwaters peak on May 24. Waterford is located behind a 29-foot seawall.
The U.S. Army Corps of Engineers plans to open on Monday the Bonnet Carre Spillway not far from the Waterford site to allow Mississippi River water to flow to Lake Pontchartrain.
Dricks said the NRC was also monitoring water levels on Missouri and Arkansas rivers, but saw no flooding at Entergy's 1,838-MW Arkansas Nuclear One station in Pope County, Arkansas; the Nebraska Public Power District's 770-MW Cooper station in Nemaha, Nebraska; or the 478-MW Fort Calhoun nuclear station in Washington County, Nebraska.
A spokeswoman for the NRC's regional office in Illinois said regulators were monitoring the situation but did not expect any impact from the rising Mississippi River on Midwest nuclear sites operated by Exelon Corp (EXC.N) and others. (Reporting by Eileen O'Grady; Editing by Dale Hudson)