Nuclear Plants in South Carolina, Missouri Face the Highest Quake Risks

WASHINGTON — The U.S. nuclear power reactors facing the highest risks of a meltdown from earthquakes are not in tremor-prone California, but states including South Carolina and Missouri, an analysis of government data published on Thursday said.

The chances of an earthquake leading to meltdowns are small, but the results would be grave. A tsunami generated by a 2011 earthquake led to the meltdowns of three reactors at the Fukushima Daiichi nuclear power station in Japan, causing radiation releases and mass evacuations.

The U.S. reactor facing the highest risk is Duke Energy Corp’s H.B. Robinson near Hartsville, South Carolina, according to the analysis by the Union of Concerned Scientists.

Robinson faces a one in 7,700 chance annually that a quake would cause a meltdown, said the analysis, based on Duke’s estimates submitted to the U.S. Nuclear Regulatory Commission (NRC). That risk is five times higher than for each of PG&E Corp’s two Diablo Canyon reactors, the only ones left in California. Those reactors are scheduled to be shut in 2024 and 2025.

The three reactors at a Duke plant called Oconee in Seneca, South Carolina, face a one in 17,500 chance of a meltdown annually, according to the analysis.

All Duke nuclear plants are in compliance with NRC requirements for earthquakes, and the company has bolstered structures, systems and components, said Mary Kathryn Green, a company spokeswoman.

Ameren Corp’s Callaway reactor in Fulton, Missouri faces a one in 13,800 chance of a meltdown annually, the analysis said. Barry Cox, the site vice president at Callaway, said the plant invests millions of dollars on protections against earthquakes and other natural disasters.

Edwin Lyman, the director of nuclear power safety at the Union of Concerned Scientists, who wrote the analysis, said that the NRC should not approve license renewals for Duke’s reactors unless the company does more to guard against risks.

The NRC is satisfied that Duke has made “binding commitments” to install permanent fixes at Robinson and would assess earthquake risks in a license renewal application, said spokesman Scott Burnell.