A Perfect Storm of Planetary Proportions
Hundreds of Fukushimas?
In a massive geomagnetic storm that could trigger a long-term power outage across large portions of the globe, the world's 400-some nuclear plants would be particularly vulnerable to catastrophic failure, for two reasons.
First, as events in Japan last March made clear, nuclear power plants often have inadequate backup power on-site. At the Fukushima Dai-ichi complex, even if the diesel generators had not been flooded, they had only enough fuel for seven days, the industry norm.
To sustain emergency operations beyond a week, all nuclear plants require a functioning connection to the grid. That's because even after nuclear fission ceases, fuel rods in the reactor cores and spent fuel pools continue to generate decay heat for years, requiring cooling with water circulation pumps. It can take several megawatts of power to operate that equipment. So when both on-site and outside power supplies suffer a long-term outage, as they did at Fukushima, the result is a core meltdown. Even worse would be a fire in a spent fuel pool, which can hold 10 times as much fuel as the core but has no containment structure.
Nuclear plants are also vulnerable because they're so big. To feed a gigawatt of electricity from a nuclear plant into the grid requires many high-voltage transformers and transmission lines, and each connection is an entry point for geomagnetically induced currents. In a comparison I did of nuclear plants versus other types of power plants and substations, there were 50 percent more GICs at nuclear plants than at other facilities.
So a massive solar storm that knocks out nuclear power plants' ability to transmit power and destroys their backup power systems could very well trigger dozens or even hundreds of meltdowns.