NRC discusses Duane Arnold license

Potential impacts of low-river flows and archaeological sites at the Duane Arnold Energy Center are the only red flags in a preliminary supplemental environmental impact statement discussed by the Nuclear Regulatory Commission here Wednesday.

The preliminary document found the potential impacts only “small to moderate.” It advises that the agency finds them “not so great that preserving the option of license renewal for energy planning decision-makers would be unreasonable.”

No members of the general public attended or commented Wednesday afternoon at a public meeting on the findings at Hiawatha City Hall. A second session was scheduled Wednesday night.

The document identified “small to moderate” potential environmental impacts on aquatic habitat and human uses of the Cedar River from water withdrawal by the plant during drought periods when the river's flow is greatly reduced, NRC project manager Charles Eccleston said. It also identified a lack of plans and procedures in place by NextEra Energy, the plant's operator and majority owner, to ensure that no archaeological resources would be impacted by future construction on the plant site.

The plant obtains water from four wells and the adjacent Cedar River. Under normal operating conditions its water removal would be only about 0.6 percent of the average river flow, but during periods when the river's flow is down to 13 percent of normal, it would be 5 percent of flow.

NextEra Energy hasn't proposed construction of any buildings or transmission lines in the 20-year extension period, which would begin in 2014. It has prepared a plan for the NRC that would ensure that archaeological sites are identified before any construction is undertaken, company officials said.

Past archaeological surveys have identified four archaeological sites, mainly the remains of past farmsteads, some of which could be eligible for historic protection.

A NRC decision on the license is expected by the end of the year.