Oconee flood protection improvements complete

20 June 2016

Eight years after requesting information on flood protection at the Oconee nuclear power plant, the US Nuclear Regulatory Commission (NRC) has concluded that modifications carried out by Duke Energy would adequately protect the plant from a potential failure of a nearby dam.

Oconee (Image: Duke Energy)

Oconee's three pressurized water reactors are located on the shores of Lake Keowee, South Carolina, 12 miles (19 km) downstream from the 385 feet (117 metres) high, 1750 feet (533 metres) long dam on Lake Jocasee. The dam incorporates the Jocassee Pumped Storage Hydroelectric Station, built in 1973. It is one of two pumped storage plants used by Duke Energy to provide extra energy at peak periods.

The NRC requested information from Duke about external flooding provisions at Oconee, including the potential failure of the Jocassee dam, in 2008. Duke submitted its detailed flood analysis in 2010, after which the NRC issued a confirmatory action letter documenting the commitments the company had undertaken to complete. The same year, Duke implemented some interim compensatory measures which were inspected by the NRC.

In 2012, following the March 2011 accident at Fukushima Daiichi in Japan, the NRC issued another letter to Duke requesting additional information on flooding as part of the regulator's initiative to ensure that lessons learned from the Japanese accident were applied to all US nuclear power plants. Duke accordingly submitted its flood hazard re-evaluation report in 2013 and a revised version in 2015. The NRC accepted the 2015 report as meeting the terms of the 2010 confirmatory action letter.

Modifications implemented at Oconee have included building new or enhanced flood walls and moving power lines and equipment to less flood-prone locations. In April, Duke informed the NRC that all the modifications have now been completed. The NRC has now completed its final inspections of the work.

NRC Region II Administrator Cathy Haney said that the long time taken to resolve the flooding issues at Oconee had been necessary to ensure that all the best analyses were used, that information from Fukushima was incorporated and that the plant modifications had met all requirements. "The completion of the commitments in the confirmatory action letter gives the NRC confidence that the Oconee plant is adequately protected from external floods, including scenarios involving the failure of the dam," she said.

Researched and written
by World Nuclear News