I grew up in the shadow of 1964 Alaska earthquake, the second largest in recorded history. The quake of ’64 registered a magnitude 9.2, and the Tohoku earthquake that precipitated the fukushima nuclear disaster registered a 9.0. I remember seeing photos all through my childhood of buildings cut in two, of sections of paved street that were torn, one side suddenly ten feet higher than the other. When I was living in Anchorage, there were stretches of ghost forests; areas where the land had subsided in the ’64 quake and filled in with seawater, becoming salt marshes. Even the hardy and scraggly sitka spruce couldn’t survive in those black marshes, and with the land too low to drain, to wet to build on and too salty to grow anything on, the ghost forests remained.
Children in Alaska go through earthquake drills all through their childhoods. I remember one earthquake that lasted only a second or less… in the time it took me to take three hurried steps to the door of my bedroom, it was already over, but it was so intense that it felt like a truck had hit the house. I remember hearing that it was something around a magnitude 5. It was probably around two in the morning, and I stood in a long nightgown, feet spread and arms holding on to the door jamb, and I heard my father’s voice from the darkened house ask, “is everyone okay?” When people talked about “the big one,” it was always about earthquakes.
I know we’ve gotten used to hearing reports of these Japanese earthquakes in recent days, but just think about it. I’ve lived in earthquake zones for most of my life, and I cannot imagine living somewhere where there are three to four strong earthquakes a year. I can only guess that earthquakes would dominate almost every waking moment, be it subtly or blatantly. As strange as this seems, it is completely expected for a large earthquake. After the 1964 earthquake in Alaska, ten aftershocks of magnitude six or greater were recorded in the first day, and the aftershocks continued for more than a year.
The Tohoku earthquake has spawned thousands of aftershocks, with more than eighty registering a magnitude six or greater, and just a little over a week ago, an aftershock with a magnitude of 7.1 hit the region. The release of tension in the subduction fault has created a lot more seismic movement in the area, and it’s not over.
With each aftershock and earthquake experienced in the area, the urgency for emptying the spent fuel pool at the Fukushima nuclear plant increases. The fuel pond of concern is perched high up in the reactor 4 building… four storeys high. The height allowed fuel to be transferred to and from the reactor vessel safely. During the meltdowns n reactors 1, 2, and 3, building four (not subject to a meltdown as the reactor had been defueled for maintenance) was badly damaged by hydrogen explosions. The building has since been reinforced, but is now sinking into the soil and tilting. The structure has to hold up not just its own weight, but also the fuel pool, which at forty feet deep holds a lot of water, and the 400 tons of nuclear fuel. The spent fuel pool at reactor building four contains 783 spent fuel assemblies, a reactor load of 548 that had been removed for maintenance when the quake struck, and originally contained 204 fresh fuel assemblies (two of these have since been removed and checked for damage). Each fuel assembly contains 60 rods (all stored fuel is LEU, though a small number of MOX assemblies were/are in reactor 3) and the fuel rods themselves are long, slender, and heavy, measuring four meters long but only a centimeter across. The Earthquake Research Institute says that the 2011 quake increased the likelihood of large earthquakes in the region. If there is an earthquake during the fuel removal operation, it could cause rods to snap and release uranium pellets. In the event of the structural failure of the pool, sufficient rods piling up in the rubble (with the new or active rods) could be sufficient to create an accidental criticality, which could result in an explosion, or a nuclear fire.
So, things get murky here. I’m not a nuclear engineer, and I can’t possibly know what’s actually going on over there. Some far left websites claim that the apocalypse is near… in fact I saw an article today from FireDogLake claiming that the fuel assemblies were already burning. This seems exceptionally unlikely to me considering that we knew that Chernobyl had happened before the head of the Soviet party did. Industry folks say that accidental criticality is impossible due to the fact that the fuel is spent, but we know that at least half the fuel was either active or brand new, and those are certainly capable of fission. So the truth is probably somewhere in the middle. A chain reaction, well, that depends on the circumstances, but let’s call it a worst-case scenario.
An exposed nuclear fire was part of what made Chernobyl such a wide-spread disaster… the uranium and graphite blob left burning for days lofted fission byproducts and contaminated particulates high into the atmosphere and spread them all around the northern hemisphere. Now, the defueling process for the pool is complicated by the damage that the building has sustained. The pool used to have a rig above it designed to lift and move fuel assemblies, and it was guided by a computer that knew exactly where each assembly was. Since that rig is now destroyed, TEPCO has had to construct a crane over the top of the building for removing the assemblies, including a support structure, using many times the quantity of steel in the Statue of Liberty. The crane will be operated by a person who will be moving the assemblies by sight. It’s thrilling, really, to think of this, a technical feat unlike any in our history, being done by a guy with a crane. It’s like something out of a movie.
As for me, I’m just a child born of earthquakes in the late cold war era, watching all of this progress with a fascination that some might consider morbid. I don’t think of it that way… I just think that this has been a story almost as dramatic as the tale of Chernobyl’s liquidators, and I can’t look away.