In 1859, a huge solar storm injected so much energy into the atmosphere of the Earth that it caused major damage to the early power grid and the telegraph system in the United States. Some telegraph operators were shocked by arching electricity in their equipment. Fires broke out and generating systems crashed. This was referred to as the Carrington Event. Since that time, we have built an amazing but vulnerable civilization based on electrical power.
Recently, a huge solar flare just missed the Earth. Had it happened a week before, it might have cause serious damage to our electrical infrastructure as well as the shell of satellites orbiting the earth. The sun has eleven year cycles of solar activity. There are larger fluctuations in solar output that play out over decades and centuries. Historical records suggest that Carrington Events happen about every five hundred years so we will have a new Carrington type event eventually.
If we have a Carrington Event now, it could fry the entire electrical grid including generators, transmission lines, motors, electronics, etc. Without electricity and electronics, our civilization will collapse. We need electricity for manufacture, transportation and storage of food. It is estimated that most supermarkets in most cities have about a week or two worth of food. Without restocking, the food will disappear in weeks. We need electricity to treat water and sewage so drinking water and sewage systems will fail. We do have emergency generators but they generally run on diesel fuel. Once their onsite fuel is consumed within days of the disaster, there will be no more fuel because electricity is needed to pump the fuel out of tanks. Industry needs electricity to function so there will be no way to rebuild our electrical infrastructure. With cascading failures of energy, food, water, industry, transportation, etc. it is likely that billions of people will die in the first year and the rest of the human race will become hunter gatherers living in the ruins.
We have a hundred operating nuclear power reactors in the United States. They all have spent fuel pools where old fuel rods are cooled with water for years as they become less radioactive. Most of the spent fuel pools in the United States are rapidly filling up. If there was a Carrington Event, the national grid that supplies the electricity for the pumps that circulate the cooling water in the spent fuel pools will be gone. Emergency diesel generator will kick in automatically. Within hours or days, the emergency supply of diesel fuel will fail. What little fuel remains in the cities will be used by emergency vehicles and the military fighting fires and civil disorder. The spent fuel pools will heat the remaining water and it will boil off. Radioactive steam will be released. Once exposed to the air, many of the spent fuel rods will spontaneously burst into flame. Hydrogen gas generated by the cladding on the fuel rods will explode, blowing up the buildings housing the spent fuel pools. Smoke, steam and radioactive particles will spew out across the landscape. The Chernobyl disaster in Ukraine in 1986 irradiated an area the size of Alabama. One hundred burning spent fuel pools would likely cover the whole United States with radioactive fallout.
So, in addition to the destruction of our civilization by a Carrington Event, there will be a cloud of radioactive particles falling on the survivors in the ruins and shortening their already wretched lives. Unlike other problems that can arise at particular nuclear power plants, this disaster will be universal. There is no way that we can prevent a Carrington Event which could happen at any time. And, given the guaranteed destruction of human civilization, the burning spent fuel pools will only be adding insult to injury for the few survivors. We may be able to harden our electrical grid and our electronics to the point where they could survive a Carrington Event if we have enough time but only time will tell.
