Sitting here in Tokyo, I find myself cautiously optimistic about the potential for TEPCO to get the reactors at the Fukushima Dai-ichi plant under control. Things have not gone well up there, and the folks running the show have done an amazing job of reacting to circumstances for which the plants simply weren’t designed to handle. My hat goes off to them.
So far, it’s unknown whether there’s been a core meltdown, partial or otherwise, in either of the reactors. One hope that there hasn’t been such an event, as a meltdown definitely complicates subsequent cleanup. And despite the apparent containment of any significant radiation, we’re not out of the woods yet with regard to significant aftershocks.
The reactors in question are some 40 years old and were within 10 years of their end-of-life. I use the past tense there because the use of sea water and boron to cool the reactors was an act of desperation that effectively removed the reactors from any hope of future use. The combination of boron and salt water is highly corrosive, so these two cores will be forever silent.
So, yes, I’m cautiously optimistic. I’m not, however, blind to the risks and reality of our situation here.
With the old age of the reactors comes the fact that they’ve lived through a lot of temblors in their day. They were also never designed to handle an earthquake of magnitude 8.9 or tsunami of 7 metres. As such, the risk really does remain that a few really significant aftershocks or another sizable tsunami or two could compromise containment. I don’t expect this, but it is a possibility.
Adding to the complications is the issue of MOX fuel. Dai-ichi #3 uses MOX (mixed oxide) nuclear fuel that is a blend of recycled plutonium and uranium oxides. MOX fuel complicates cooling because it tends to run hotter than a conventional uranium reactor.
Dai-ichi #3 has had the problem of the fuel rods being partially exposed, even with the efforts of operators to fill the core with sea water. Due to the issue of exposure, the hotter rods are more prone to experiencing meltdown. Meltdown is a problem that I hope they’re able to avoid.
If the #3 reactor containment fails, the MOX fuel dispersal will create an extremely dirty environment that is potentially more hazardous than that of a conventional reactor. So, keep your fingers crossed and your hopes up. The more we expect the best, the better the chances of the best transpiring.
My heartfelt best wishes to those on the front lines in helping keep the rest of us safe. Godspeed.