Fukushima: What I Know and What I Think

For the last week, I have been glued to a computer trying to find some accurate information on the Fukushima reactors.  Believe me, it is extremely difficult to come by for even someone who knows what they are looking for.  I really don't know how any normal person could sit down and try and figure out what is going on there.

Today has been kind of a fork in the road it seems for the media.  It seems that those news outlets that are intent on fear mongering and predicting the worst are getting worse.  They are hyping up their rhetoric and calling this an apocalypse, even though the situation has changed little since yesterday.  I can't say this wasn't to be expected though and I know that it will continue.  Fortunately it seems that a lot of the media is starting to take the time to learn what all this means.  They are asking questions like "what does a nuclear meltdown mean?" and "how much radiation is bad for us?" and these seem to really be changing the attitude among rational thinkers.

Today I just wanted to share what I have been able to make of the news coming out of Japan right now.  There is a lot of the mainstream television media that seems to be predicting the worst and using exercises of caution to prove that something is going to happen.  They are claiming that the reactors are out of water and that the meltdown is imminent.  I have to admit that they have the world watching.  Fortunately for the rest of us, I think what we see will only disappoint our natural desire to watch disaster.

The last official report that I can find came out yesterday afternoon.  As of then, it seems that reactor No. 3 had the lowest water levels, which was leaving about 1.9 meters of the core above the water line.  This is roughly six feet of the core for those of you that don't like dealing in metric units.  The other reactors are in better condition than this, most of them significantly better. 

Reactor No. 3 was also causing concern about its containment vessel being breached after being rocked by several hydrogen explosions.  As of the official report yesterday from the plant, the workers state that the possibility of the containment vessel being breached was extremely low.  The pressures in the reactors are also under control, much more so than the days right after the earthquake.

Being that the water levels are low around the reactor cores, I am sure that the cores have experienced some melting.  This just means that the uranium inside the fuel rods gets hot enough that it melts.  Prior to this happening though, the cladding containing the fuel pellets will melt first, which will cause the fuel pellets to fall into the water.  This was also designed to happen in case of low water levels. 

What does the melting mean as far as risk?  Well, not that much.  I must again point out how strong the containment vessels around the reactors are.  In case of a full meltdown, it is highly unlikely that containment vessel could be breached.  The plants were built to contain any core disaster inside that vessel, and that is what we are seeing so far.

Many people think that helicopter crews are making last ditch efforts to dump water into the reactor by dowsing the reactor as they fly over.  Well, this is just simple misinformation.  Again, the reactors are sealed and closed.  We can't get to them to simply dump water into them, which is a good thing as far as risk from the core goes.  The media seems scared of images of helicopters flying over the sight dowsing the sight with water because this is what was seen at Chernobyl.  There, the reactor had no containment vessel and blew its lid off when it flash boiled the water inside.  This made it open to the atmosphere and helicopter crews were used to drop neutron absorbing materials into the blaze to try and stop the reaction.  Such is simply not the case here.

What people are seeing with the helicopters are efforts to keep the stored fuel closed.  At the Fukushima reactors, the spent fuel rods are stored in pools directly above the reactors.  Due to limited space in Japan, the fuel is stored perhaps in too tight of quarters, meaning that when the water level gets low, the fuels can begin to heat up.  Because of this, the water level in the pools must be maintained, which is what the helicopters are trying to do by dumping water into the pools.  Unfortunately, the pools are large enough that their efforts are kind of like spitting in the lake.  I have seen estimates that it would take more than sixty helicopter drops to raise the water level in one of the pools by one meters.  Instead, ground crews are now working using large hoses and pumps to move water in the ponds.  The water temperatures in the ponds are not yet to boiling and efforts are trying to keep the situation this way.  Incidentally, most of the radiation release so far from the sight has been from water evaporating from these pools.  This is only low level radiation though, not considered dangerous to the public's health.

As far as bringing an end to the situation, there does seem to be light at the end of the tunnel.  Crews have been working to establish a new direct power line to the Fukushima reactors.  It is not said when the line is to be completed, but I read that the line is near completion and will be tried as soon as possible.  The new power lines will then be able to run the cooling pumps that should have maintained the reactor in the first place.  Once reliable cooling has been established, any fears of further mass release of radiation will be over.  We just hope that the pumps work when the power is restored.  This would be one of the few strokes of luck that workers have had though since the earthquake occurred.

As far as the radiation currently escaping from the plant, I know little.  It seems that the maximum dose rate measured at the front gate of the Fukushima facility was 1,530 micro sieverts per hour.  This seems like a large number, but it really is not.  Doing a little more research shows that a single chest CT scan yields a dose of about 6,900 micro sieverts (h/t to Rod Adams at Atomic Insights).  We are not talking about dangerous levels here, and this is at the sight itself.  As for now, it seems a little ridiculous to even talk about evacuating Tokyo, but the news makes sure to present this as a possibility.

I want to be honest here and say that we don't know for sure what will play out at Fukushima.  I can't predict the future.  There is a chance that some of the public is exposed to low level radiation.  There is a smaller chance that there might be a larger release of radiation that could make people sick.  There is even a chance of a catastrophic failure there that could kill many, but this same chance exists every day.  As a scientist, I can't ever say that there is never this chance, but I can say the risk is extremely small.  This is what the public doesn't always understand about the way scientists speak.  There is always a finite chance there is disaster, but how small of chance allows for the disaster to materialize?  That is often up for debate, but I just want to you realize a little about how scientists and engineers talk.

As for me, I still believe that the public will be exposed to only low levels of radiation, and most of the public near Fukushima will not even see that.  I know that some of the core has probably started to melt and I can see more of this happening in the next couple days.  The industry has planned for this though as required by international guidelines.  We have learned from mistakes of the past and we chose not to repeat them in the future.  This is why there has not been a significant release of radiation yet at Fukushima.

I want to leave you with a little bit of material for you to think about and perhaps motivate what you think about the situation down the road.  Mankind has always been an engineering society.  We build bridges that fall down and then we learn why they failed and build them again.  We build the Titanics of the world, but we don't stop building boats because of a failure.  We learn to put lifeboats on board and then we move on.  Our ancestors did not stop progressing because of their failures, and I think just as much as it is our duty to hand our children a better world, we need to hand our children our progress to build off of.  If we don't do that, we have failed.  Let's build an understanding from the situation and not let fear shut us down.  There is a reason we are the superior race on the planet.