The March 2011 Japan earthquake and tsunami were an unprecedented natural catastrophe. The tsunami was brutal and lethal. Watching the video below I could barely believe my eyes. I was dumbfounded by how devastating the wall of water was. Watch it yourself. It is stunning and terrifying.
The video lasts less than 26 minutes. Just watch the speed with which the water in the inlet recedes and then returns. Imagine being there. During those brief 25+ minutes, and in the day after this devastation, roughly 20,000 people lost their lives. Mostly that was from the sheer grinding action of water and debris: as you can see, the torrent of seawater rushing inland swept up everything in its path. The vast majority of people unfortunate enough to be caught in the maelstrom would not have lived longer than about a minute before colliding with some fast-moving object. And whoever did not die from physical trauma would have perished from exposure to ice-cold seawater. Look at the clothes the people in the video are wearing. That’s what you wear when it is cold outside. Water is about the very last thing you want to come in contact with on a day like that.
That occurred 4394 days ago. Readers might recall that day: it began with news that a nuclear plant in the tsunami’s path had had its power knocked out and was in danger of melting down. This was presented in news reports as a very serious thing. I remember wondering, how serious really can it be? I remember looking up the Fukushima Daiichi nuclear plant, which up to then I had never even heard of. I learned that it is a six-unit generating station, and that all six units are boiling water reactors (BWRs) of American design.
Well, American designed BWRs feature heavy steel pressure vessels in which fuel sits immersed in water. Water is pumped in using electric pumps; if those pumps stop working then the heat from the fission reaction will boil off the water. If you own the reactor, that is a very bad thing: it means the uranium fuel will become uncovered. Without water to carry the heat away the fuel will heat up from the decay of fission products until it melts. That is called a meltdown. If a meltdown occurs, kiss your reactor goodbye. It is toast.
But how dangerous is this event to people who might be within a few kilometers of it? You may be surprised to know it is not really that dangerous at all.
It is important at this point to remember the universal Laws of Thermodynamics. Much of the popular culture lore about meltdowns comes from the 1979 Hollywood science fiction thriller The China Syndrome. In that film, a meltdown is described as an event in which nuclear fuel melts and then continues to heat up so that it melts everything in its path—first the bottom of the reactor vessel, then the containment building, then the ground underneath the reactor, then the entire planet. Eventually, according to a character in the Hollywood movie, it emerges literally on the other side of the earth.
Does The China Syndrome square with reality? Can a glob of molten uranium fuel really bore its way through the planet? Of course it cannot. (Well it can, but only in a Hollywood movie.) In the real world, such an event is forbidden by the Laws of Thermodynamics and particularly the Second Law. There is simply no substance in the universe that can spontaneously extract heat from its surroundings and then transfer that heat, and more, back to the surroundings. That immutable physical fact is embodied in Rudolf Clausius’s famous statement on the Second Law.
(The China syndrome is also impossible due to another universal law of physics: the law of gravity. Apparently, nobody thought to consider what would happen once the molten glob had reached the centre of the earth. For it to continue on out to the other side, it would have to travel upwards. Try travelling uphill some time. You can immediately feel how difficult it is. That is gravity.)
In The China Syndrome, at the point where the utility executive intones the implications of the syndrome (at about 1:40 of this Youtube video), there should have been a laugh track.
The China Syndrome was released to movie theatres in early 1979. Twelve days after it was released there actually was a meltdown at a U.S. nuclear plant: the Three Mile Island (TMI) accident. Through a series of human errors which led to misreading of reactor control instrument data, one of TMI’s reactors partially melted down. News reporters, apparently going on information from the movie, went into a frenzy. A national “crisis” ensued. The president got involved.
And the upshot? From the perspective of public and environmental health, TMI was a consequence-free event. There was no damage to the environment. Nobody died. Nobody even got sick.
The reason for this is simple. Not enough of the potentially dangerous stuff inside the reactor made its way outside the reactor. A glob of molten uranium did indeed sag to the bottom of the reactor vessel. It even started boring its way through, in the direction of the other side of the planet. It traveled less than two centimeters into the wall of the steel pressure vessel, then stopped. Why did it stop? Because it cooled, then turned back into solid material. That’s the Second Law of Thermodynamics at work.
I was aware of all this on the morning of March 11 2011, 4394 days ago. So when a CBC reporter called asking for my opinion on the implications of a meltdown at the Japanese reactor whose power had been knocked out by a tsunami, I told her I expected no human casualties from such a meltdown. Other people who know nuclear technology better than me said and wrote the same thing at about the same time. On the Sunday following the tsunami, I wrote in to a CBC talk show reiterating this point; Rex Murphy read my note out to a live audience. And I have made this point at every opportunity in the 4394 days since.
And we have been proven right. Nobody has died from radiation at the Fukushima plant. Likely nobody will.
Unfortunately, my small voice and the voices of others who know what they are talking about did not prevent a manufactured tsunami of hysterical media coverage of the Fukushima situation from drowning out coverage of the real tsunami, which was the real catastrophe. Fukushima coverage appears to still draw from information from The China Syndrome, a Hollywood science fiction thriller.
Look at the tsunami video again. That was the real catastrophe. What a pity the world media can’t tell a real tsunami from a manufactured one.
Excellent feature that the media will never have the gonads to carry!
One issue which has seemingly gone under the radar of ardent environmentalists and news media is in that boiling torrent of water plowing inland through coastal towns and smalls cities is a toxic brew dredged up from pulverized homes to factories composed of household and industrial chemicals, gasoline, agricultural insecticides, raw sewage, cemetery remains, storm drain jetsam, garbage, lab and hospital biological agents and lord knows what else, the majority of which toxic cocktail of slime and sludge not washing back out to sea but remaining beached deep inland to ooze and percolate into the earth and water tables in a far far vaster region than a trickle of radiative water in Fukushima could ever do. Call this Love Canal cubed every square mile. What is the water table contamination potential here — and why isn’t it being played up at least a tenth that of Fukushima’s leak? There should be SOME story or research on this — the media HOWLS over a farmer’s misuse of insecticide on oranges, but not a peep about an infinitely more pernicious issue as this? But the silence is way more disturbing than anything Fukushima’s stirred up.
Just had to repost over this video whom SO many need a reality check with over being frightened witless over a phantom disaster at Fukushima vs the real thing happening here before your eyes with real people and buildings under attack, crimbling and drowning and dying, and not by imagined nuke Doomsday nightmares. If Japan had any proirity to address, it ought be making their coasts and infrastructure more tsunami resistant. And anti-nukes and media need to see this and get some hard down-to-earth perspective over what’s a catastrophe and what’s not.
“Well, American designed BWRs feature heavy steel pressure vessels in which fuel sits immersed in water. Water is pumped in using electric pumps; if those pumps stop working then the heat from the fission reaction will boil off the water. ” Not so. The energy causing meltdowns comes from from radioactivity of the brew of fission products in the fuel elements, see http://mitnse.com/2011/03/16/what-is-decay-heat/.
The fission of U235 is ineffective in the shut down reactor because too many neutrons are captured by the control rods. Paradoxically the absence of water in the melted corium insures that the fission reaction can’t be restarted. A moderator is required to slow the neutrons to increase the capture cross section.
The last that I read it was undetermined whether corium from the reactor cores had actually penetrated the Fukushima reactor vessels. There was no penetration of the TMI vessel. I don’t know if anyone has modeled what would happen if no cooling water was ever supplied to a melting reactor core, but the Doomsday scenario is a fantasy.
Northcoast, thanks — but I don’t think I’m incorrect in saying that the fission heat will boil off the water if the coolant pumps stop working. Fission heat boils the water in the first place, doesn’t it? I mean, if decay energy were sufficient to boil that mass of water then freshly discharged spent fuel could turn turbines instead of just warming water.
Of course, once the water is boiled off there is no fission reaction; as you say, slow (in the case of a BWR, water-slowed) neutrons are needed to maintain a critical reaction in the fuel. So yes, decay energy causes the actual meltdown.
In the case of a feed pump/recirc pump stoppage, the fission reaction would almost entirely stop due to moderator temperature/voiding. In the case of Fukushima, the rods inserted within seconds of the earthquake. All of the water which boiled off was phase changed with decay heat.
Decay heat has more than enough energy to boil off massive quantities of water. 1% of 3400 MW is still roughly the power used to drive the Titanic through the water. Additionally, spent fuel decay heat can and does drive a turbine. That’s exactly the principle that the Turbine-driven Aux Feed Pump (PWR) and RCIC pump (BWR) uses.
Maybe it depends on how we parse the words. I think there is an advanced reactor design that would use decay heat to drive coolant pumps in an emergency.