Nebraska nuke plants 'remain safe'
The top US nuclear power regulator has said both of Nebraska's nuclear power plants have remained safe as they battle floodwaters from the bloated Missouri River.
Nuclear Regulatory Commission Chairman Gregory Jaczko visited both the Fort Calhoun and Cooper nuclear power plants in eastern Nebraska to see how the utilities that run them are coping with the flooding. Both plants sit on the river.
The Omaha Public Power District's (OPPD) Fort Calhoun is the subject of more public concern because the floodwaters have surrounded that plant and forced workers to use elevated catwalks to access the facility. Nebraska Public Power District's Cooper plant is more elevated.
Mr Jaczko's visit to Fort Calhoun on Monday came one day after an eight-foot-(2.4-metre) tall, water-filled temporary berm protecting the plant collapsed early on Sunday. OPPD plans to replace the 2,000-foot (600-metre) berm with a similar one early next month and then pump out the floodwaters to restore a dry buffer area.
Omaha Public Power District spokesman Jeff Hanson said pumps at Fort Calhoun were handling the problem and that "everything is secure and safe". The plant, about 20 miles north of Omaha, has been closed for refueling since April. Mr Hanson said the berm's collapse did not affect the shutdown or the spent fuel pool cooling.
Either floodwaters from the Missouri River or groundwater seeped into several of the peripheral buildings at Fort Calhoun, but plant manager Tim Nellenbach said all of the areas containing radioactive material or crucial safety gear remained dry.
Flooding remains a concern all along the Missouri River because of massive amounts of water the US Army Corps of Engineers has released from upstream reservoirs. The river is expected to rise as much as five to seven feet (1.5 to 2.1 metres) above flood stage in much of Nebraska and Iowa and as much as 10 feet (three metres) over flood stage in parts of Missouri.
The corps expects the river to remain high at least into August because of heavy spring rains in the upper Plains and substantial Rocky Mountain snowpack melting into the river basin.
Separately, thousands of residents have calmly fled from the town that is home to the Los Alamos nuclear laboratory, ahead of an approaching wildfire that sent up towering plumes of smoke, rained down ash and sparked a spot fire on lab property where scientists 50 years ago conducted underground tests of radioactive explosives.
Los Alamos National Laboratory officials said that the spot fire was soon contained and no contamination was released. They also assured that radioactive materials stored in various spots elsewhere on the sprawling lab were safe from flames.