Lessons I have learned from Fukushima.
On March 11, 2011, a magnitude 9.0 earthquake struck the Pacific coast of Japan and also caused a tsunami that killed nearly 20,000 people. The earthquake was the strongest every recorded to have hit Japan. The tsunami also set in motion a chain of events that destroyed 3 nuclear reactors at Fukushima Daiichi.
I could spend a lot of time telling you about the fact that no one has died from the small amount of radiation released or how the evacuation of people living around Fukushima was unnecessary, and how even now the evacuees have not returned, even though the small amount of radiation is even smaller after five years and getting smaller every day and is not harmful, but what would be the point?
This is all 99.9999999% of the people would hear if I tried to tell them why nuclear is still the best and cleanest form of energy extraction, Fukushima blah, blah , blah, blah…………
That is the first lesson I have learned from Fukushima.
The second lesson I have learned from Fukushima is to design and build a reactor that will can cool itself passively without any human intervention until it reaches a cold state. Molten salt reactors can do this.
The third lesson I have learned from Fukushima goes along with the second item; if the reactors are designed to cool passively (without any operator intervention) in the event of a station blackout, they will not be the 1000 MW colossus we are used to seeing. They will be smaller and can be buried. Think out of sight, out of mind. Bury the reactors! If the neighbors don’t even know they are there, awesome!
The fourth lesson is about evacuations. Don’t ever do them. Design and build reactors that don’t use water for the primary or secondary heat transfer loops that can turn to steam on a bad day and necessitate massive containment structures and where the blistering hot zirconium can disassociate water into hydrogen and oxygen and cause explosions that are amazingly bad PR for all things nuclear. These events are like honey to flies for the media. It doesn’t matter what the truth is about it being a chemical explosion. All Jane and Joe lunchbucket see is an explosion at a nuclear power plant.
If the fuel is thorium in a molten salt, it can’t melt down. It is already melted! The reactor runs at near ambient pressure not at 3,000 psi, like in a light water reactor. If there is a leak in the primary loop, the molten salt leaks out and solidifies! It does not flash into a gas that requires a massive containment building that has to withstand elevated pressure. A 20 x 20 foot concrete containment structure would be sufficient to permanently separate the radioactive fuel from the environment. Thus, an evacuation plan is never necessary and should not be required by regulations.
I learned some other things about Fukushima that I have not been able to turn into lessons. They are to irrational to cognitively process.
For example, there are about 200 million gallons of water that have been decontaminated and stored at Fukushima. There is no regulatory method to deal with them. The water has been filtered to remove all radioactive material except tritium, which being an isotope of hydrogen cannot be separated chemically from the rest of the water. The tritiated water is only weakly radioactive and should be dumped into the Pacific Ocean, but alas there is not a snowball’s chance of that happening.
Fear of all things radioactive and nuclear has destroyed the fishing industry in Fukushima, even though every fish caught is scanned for radioactivity and discarded if it is above a very small level. Maybe Fukushima should send all of its catch to Peru to make cebiche.