Weakened concrete found at nuke plant

Jun 2 - McClatchy-Tribune Regional News - Dave Rogers The Daily News of Newburyport, Mass.

Groundwater has weakened concrete surrounding an electric tunnel at Seabrook Station nuclear power plant, according to a report recently released by the federal agency that oversees the nation's civilian nuclear energy facilities.

Inspections of the plant also found instances of corroded steel supports, anchor bolts, base plates and piping.

The weakened concrete was recorded in a Nuclear Regulatory Commission inspection of the nuclear power plant that was conducted as NextEra Energy, the company that oversees the facility, seeks a 20-year renewal of its operating license. The current license expires in 2030.

According to the report, groundwater over a period of more than 10 years has saturated a small section of concrete, weakening it by 22 percent since that section was last tested in 1979.

Groundwater infiltrated concrete through a series of small cracks to form pools of water 2 inches deep in some areas, but it did not pose a safety problem for the electrical cables that are several feet off the ground. That caused deposits of calcium oxide/carbonate to form along locations on the walls and looser deposits of calcium salts at other crack locations. The most distressed area of concrete was found in the B-Electrical Tunnel.

NextEra Energy spokesman Al Griffith said the weakened concrete was first discovered during an internal inspection last summer and then reported to the NRC as part of its renewal application.

Griffith said there have been no other reported areas of concrete degradation.

"All of our buildings meet safety requirements; they exceed safety requirements," Griffith said.

Griffith said NextEra Energy will be removing groundwater using a process he called "de-watering" and then conduct further tests to make sure no other areas of concrete have been affected.

The affected tunnel is part of an underground labyrinth of buildings and other structures, which comprise a safety system used to cool the reactor following a shutdown.

Word of the weakened concrete comes at a sensitive time for nuclear power plant operators, as countries across the globe are reassessing safety issues following the nuclear crisis at the Fukushima Daiichi power plant in Japan.

In response to the nuclear accident, legislators on Beacon Hill appointed a Nuclear Oversight Committee and in early April conducted a daylong hearing on the safety of the region's nuclear power plants. During more than five hours of testimony, the committee questioned officials from the three nearest nuclear power plants -- NextEra Energy Seabrook as well as Pilgrim Nuclear Power Plant in Plymouth and Vermont Yankee Nuclear Power Plant in Vernon, Vt. -- about the safety of their plants.

During their time before legislators, NextEra Energy officials did not mention the weakened concrete.

Asked why it was not brought up during the hearing, Griffith said, "Because there's no safety impact."

Built in 1970, the Seabrook nuclear power plant generates 1,230 megawatts and powers 1.4 million homes and businesses. Six Massachusetts communities -- Amesbury, Merrimac, Salisbury, Newburyport, Newbury and West Newbury -- are within a 10-mile radius of the plant and are considered part of the Seabrook emergency planning zone.