Wednesday, May 6, 2015

Flood risk to nuclear reactors raises meltdown fears

Paul Brown in the Ecologist: ...All nuclear plants need large quantities of water for cooling so all must be built close to the sea, large rivers or lakes. This makes them vulnerable to sea level rise, storm surges and to the possible collapse of large dams upstream from poor construction, floodwater or seismic activity.

Since nuclear plants are designed to operate for as long as 60 years and need around a further century to decommission, accelerating sea level rise and more intense rainfall may present serious problems. There are currently 435 operating nuclear reactors in the world, many of them potentially vulnerable to flooding because of natural disasters. Examples from the UK, Finland and the US show that the extent of the danger is not always being disclosed.

... The same fears [of flooding] were raised in the US by the Union of Concerned Scientists after a report was leaked about the danger to nuclear reactors from dams bursting. According to a report by the US Nuclear Regulatory Authority (NRC), which had been withheld, more than 30 nuclear installations were in danger from flooding. The Commission was later accused of using security concerns to mask embarrassing information.

Among many revelations in the report was the fact that the authorities had known for a decade or more that the failure of a dam upstream from the Oconee nuclear plant in South Carolina would cause floodwater to overwhelm its three reactors, possibly causing a catastrophic meltdown The odds of the dam bursting were far higher than thechances of the accident that devastated Fukushima.

Oconee is one of the largest nuclear plants in America and has been operating since 1983. Its owner, Duke Energy, remains confident that it could shut the plant down safely in an hour, before floodwaters from upstream could reach the reactors. The NRC has decided that this is sufficient safeguard....

A 1974 image of the control room at the Oconee nuclear plant in South Carolina

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