New Hampshire: Nuclear plant faces questions from NRC

SEABROOK — The U.S. Nuclear Regulatory Commission is asking Seabrook Station for more information regarding long-term operability concerns raised in an inspection completed early this year.

Seabrook Station, which is seeking a 20-year extension of its operating license slated to expire in 2030, received a letter this week asking it to respond to concerns raised at an April 23 meeting at NRC headquarters in Rockville, Md.

NextEra Energy, which owns the plant, received a letter from Christopher G. Miller, director of nuclear reactor safety with the NRC. Miller said the recent inspection focused on NextEra's work regarding alkali-silica reactions that are affecting concrete structures.

Alkali-silica reaction refers to the impact of groundwater on concrete. The NRC first raised the issue of deterioration of the concrete in below-ground-level structures at Seabrook in a May 2011 report. Inspectors at that time discovered potentially problematic conditions, including a large amount of groundwater infiltration and calcium carbonate deposits, corroded steel supports, base plates and piping, corroded anchor bolts, pooling of water, and cracking and spalling of concrete.

In his letter this week, Miller wrote, "inspectors concluded that these structures can currently perform their safety-related functions despite the observed degradation ... however, the NRC still has concerns associated with long-term operability."

Miller has asked NextEra to provide information at the April meeting including how various characteristics of the concrete may be affected by alkali-silica reaction and the related effects on other elements of the structures, such as rebar.

Alan Griffith, a spokesman for NextEra, said the company is confident that plant operators can manage the concrete degradation issue.

"We're pleased that, once again, the NRC has made clear that it has no immediate safety concerns at Seabrook Station," he said Tuesday. "We have a comprehensive strategy in place to effectively manage (alkali-silica reaction) that includes augmented monitoring, improved analysis techniques and potential ASR mitigation actions if ever needed.

"Most importantly, ASR has not and will not impact our ability to operate our plant safely."

LINK