NRC Watching Isaac — Weekend Update

As Tropical Storm Isaac develops off the Gulf coast, one only hopes that it will lessen in force and simply bring much needed rains. But the reality is that NRC staff prepares for adverse conditions — to include hurricane force winds in excess of 75 mph — and takes action before the storm even hits the ground.

As recently as yesterday, when nuclear power plants were busy taking severe weather precautions, such as tying down loose equipment, removing debris that could become projectiles, and topping off water and fuel tanks, the NRC ramped up staff to assist the resident inspectors at three plants.

Currently, Waterford and River Bend in Louisiana, and Grand Gulf in Mississippi have an additional six NRC inspectors who will ride out the storm inside the plant alongside the plants’ emergency and operations personnel. Additional staff are ready and waiting to relieve this group, and will be monitoring plant activities to ensure safe operations on a 24/7 basis.

As news agencies report on Isaac’s projected path, the NRC Region IV incident response team in Arlington, Texas, monitors the National Weather Service and uses specially created software to monitor wind speeds at the plants. This team went to work at noon today and will provide continuous coverage throughout the night as it stays in touch with the resident inspectors, FEMA, state and other federal partners.

We will keep you posted about the plants’ status after the eye of the storm makes landfall.

Weekend Update: After FEMA assessed the status of emergency services in the area and the NRC reviewed the plant’s onsite emergency preparedness program and infrastructure, the NRC has determined Waterford 3 can resume power operations.

Thursday Update: While the NRC’s Region IV incident response team will continue to watch the storm’s path and additional NRC inspectors will stay at the plants through the duration of the storm, the region has exited our first level of response mode of operations known as “monitoring mode.” Currently, Waterford remains powered down and the NRC will have to approve restart. Additionally, FEMA will have to determine that the evacuation routes in the area are passable. Once the storm has passed, NRC inspectors will independently verify that key plant systems and structures are undamaged and able to support plant operations.

Wednesday Update: The NRC’s Region IV Office in Arlington, Texas, activated it Incident Response Center Tuesday night to track Hurricane Isaac and monitor the activities of the nuclear plants in the storm’s projected path. Yesterday afternoon, the Waterford site in Louisiana began a controlled plant shutdown due to the possibility of adverse conditions generated by the storm. Both the River Bend plant, in Louisiana, and the Grand Gulf plant in Mississippi remain at full power.

Lara Uselding
Public Affairs Officer
Region IV

Keeping Cool: Record Temperatures and Nuclear Safety

The unusually hot summer across much of the country has not only taken a toll on our lawns and plants, it’s also slowly raised the temperature of some of our lakes and rivers. Many nuclear power plants rely on lakes or rivers for water to cool the plant. So, what is the effect of slowly-rising water temperatures?

If the temperature of the water used to cool the plant rises too high, a plant may have to reduce the amount of electricity it generates. Reducing electrical output reduces the heat generated by the plant, so that the plant can be safely cooled even with higher-than-normal temperatures of intake water.

The NRC requires that intake water temperature be continuously monitored to make sure that appropriate action is taken before any safety limits are exceeded. This year, a few plants have had to either reduce power or seek special NRC approval in order to temporarily operate with higher-than-normal cooling water temperatures. Unit 2 of the Millstone plant in Connecticut has had to temporarily shut down because of warm water temperatures.

What about water that is discharged from a plant after it has been used to for cooling? If the temperature of that water is too high, it can harm aquatic life or have other impacts on water quality. So, a plant may need to reduce electrical output to keep the discharged water sufficiently cool, or request special permission to exceed permissible temperature limits, which are set by other federal and state regulators with responsibility for water quality.

With autumn approaching, the temperatures will fall. Even after the summer heat passes, the NRC will continue to ensure plants closely monitor the temperature of their cooling systems. Whatever the season, safety remains the agency’s top priority.

Jared K. Heck
Regional Counsel
NRC Region III