Thursday, May 5, 2016


This is going to be a highly personal post, on a difficult (for me) issue, so I’ll kickstart it by resorting to a cultural icon. You probably remember the segment in the first movie of the Lord of the Rings trilogy, right after Gandalf suggests to Elrond that may be the humans could reunite under a legitimate king and be a force to be reckoned with against Mordor, when Elrond cuts him short stating that “he was present when human strength failed” (and since then, only three millennia in the past, he took humans to be a bunch of good-for-nothing pansies, talk about having long memories of relatively minor slights and grievances!)

Quick aside: one can only wonder, knowing everything that came later, if the elven king’s wisdom did not fail in a similarly epic scale that day, as all he had to do was kill Isildur, take the ring from his corpse and cast it to the fires of mount doom, ending the threat of Sauron there and then… of course he didn’t (he would have pre-emptied not just the following two films of LoTR, but the three of The Hobbit as well, but let’s not get too metanarrative here), and maybe the self-reproach for such misjudgment was (repressed, and thus causing some overcompensation) somewhat behind his cavalierly dismissal of another race’s capabilities.

But now, back to my confession, I hereby declare, in front of the whole community of the Interwebz, that I was similarly “there” the day, a bit more than five years ago, when the strength of nuclear engineering was tested and was found wanting.

I distinctly remember the 11th of march, 2011. Late afternoon that day I was talking with the president of my company when we were interrupted by one of our directors, who acts as our liaison with the CSN (Consejo de Seguridad Nuclear, Spain’s regulatory body regarding nuclear energy), to tell us that Japan had been hit by a 9.0 magnitude earthquake (the most powerful ever recorded there, and the 10th most powerful on Earth since we keep records) and some of their nuclear reactors had to be stopped. One location in particular, Fukushima, was close to the epicenter and in the coast, but the first information we received was that it had resisted the quake (a significant feat, as it was well above the “design reference”, which means the plant had been designed to sustain a significantly less powerful shaking… but the safety coefficients engineers always apply seemed to have been enough this time) and was in a “hot stop” (subcritical, controlled state). Our first reaction was of relief (just sustaining such quake, again, is an impressive engineering feat –attested by the destruction of many buildings in the same event, in one of the most seismically prepared countries of the world), but we knew that the most severe test was yet to come, as after such a violent quake near the coast a huge tidal wave (a Tsunami) was to be expected. Our president ordered all our nuclear experts to be available on call 24 hours a day for the following weeks, and to transmit the CSN that whatever support they may offer Japan’s regulators and TEPCO (the operator of the plant) would be fully backed by us.

That was not an empty offer, as our company houses a significant amount of engineers with deep knowledge of the BWR reactors manufactured by GE like the ones used in Fukushima, because they have worked in the construction and operation of a Spanish plant with the same technology (Sta. María de Garoña) and furthermore because they have been involved with GE in the development of the next generation of the same technology (the ESBWR). We soon learned that the tsunami protection wall in Fukushima was a bit above 6 meters high, and that an earthquake of that magnitude would produce a wave that would reach the coast up to 40 meters above its usual level, so things didn’t look too brilliant.

The following days would bring with them a rosary of bad news that confirmed our worst expectations. The tsunami indeed passed easily over the wall, and washed everything around the plant, including the tanks containing the fuel for the emergency diesel motors that should keep the cooling water circulating and preventing the fuel rods from melting. The wave didn’t affect the reactors themselves, safely protected by an almost impregnable contention building. But remember those reactors had been safely stopped (by the forceful injection of control rods made of boron between the fuel rods, a procedure called SCRAM that depletes the reactor core of the neutrons with the energy to keep the fission chain reaction going) so the plant was producing no energy, and had to rely on the external grid to power said cooling system. Unfortunately the external grid had been similarly washed away, and it would take months to restore the main lines. Not having the cooling system circulating the water around the fuel rods is a very bad thing, as the long fission chains within the spent fuel produce lots of heat, that in turn causes the rods to overheat, melt and produce while melting significant amounts of a highly flammable gas (the zirconium alloy that covers the fuel reacts with water to produce zirconium oxide and… hydrogen; remember the tragedy of the Hindenburg? That’s a nice illustration of what the combination of a high concentration of hydrogen and some heat can do).

So with all that hydrogen concentrating freely within the reactor buildings (the operators didn’t want to ventilate them, and thus lower the dangerous concentration, because at that stage the hydrogen was full of suspended radioactive particles in the form of aerosols, that would have been carried outside, and every nuclear plant operator in the world has been trained to absolutely, by any means, come what may, avoid letting any extra dose of radioactivity reach the public) it was just a matter of time since a loose spark, or the simple contact with some overheated surface, made all that hydrogen to explode in a stupendous conflagration that blew up part of the contention building, effectively freeing highly radioactive particles to be carried by the wind to the unsuspecting public (well, not so unsuspecting, as the reluctant authorities were aware of the dangers and had initiated the evacuation of the closest population).

The rest, as they usually say, is history, but I want to dwell a bit more in the moment when the main reactor was exposed (knowing that its integrity had been breached and that part of the melting core was, for all practical purposes, burning at the open air). We nuclear engineers pride ourselves of the soundness of our design principles, and the robustness of the results we have reached with them. The iconic accidents in nuclear power history have been either inconsequential for the public (Three Mile Island) or due to a mixture of bad design and foolish operation (Chernobil) that we disregarded as an aberration and a clear violation of our code of practice. Between those principles two occupy pride of place: defense in depth (having multiple layers of protection –the fuel rod cladding, the reactor vessel, the reactor building lining- to ensure no radioactive particle can escape to the open atmosphere) and avoidance of any “single point of failure” (identifying any event that may cause such uncontrolled release of radioactive particles to the atmosphere, and making that event not just unlikely, but ludicrously so, by adding redundancies and safeguards that prevent it from ever happening or, if happening, causing the adverse effects). The image that we had all been trained to prevent, the state of the world we explicitly tried to avoid, the stuff our nightmares are made of is precisely what I remember distinctly seeing in Fukushima then: an exposed core of burnt fuel (the most poisonous product of our trade), polluting the environment with its deadly fumes for days (and then weeks) until it could be brought under control again (it is questionable to what extent it is controlled even as of today, as the “lava-like fuel containing material”, LFCM, also known as corium, probably has melted not only the vessel but most likely the concrete slab under it, and only God knows what depth under the plant’s soil it may have reached, making the management of the underwater currents used to cool it pretty complex). I guess like an urbanist confronted with Mexico DF Shantytowns, like a Keynesian economist confronted with the ECB monetary policy, like a neurosurgeon confronted with a XIX century lobotomy, I felt like what I held more dear had been spoiled horribly and laid in its rotten state to die in front of all the world who could only contemplate aghast such ugly agony and pontificate how such a monstrosity could have come to be, and what to do to ensure it never again happened (without much in the way of understanding).

What, indeed, to do? Some normally sensible commentators (I remember Anne Applebaum in the WaPo, but there were many more) advocated for the wholesale rejection of nuclear energy. If the methodical and meticulous and careful and attentive Japanese could not be trusted to operate their reactors safely, who could?  It makes you shudder to think there are nuclear power stations in Mexico (Laguna Verde), Brazil (Angra dos Reis), Argentina (Atucha)… I don’t like to resort to stereotypes, and you can find everywhere (including, of course, the three mentioned before as negative examples) extraordinary professionals that can successfully compare with the best of the world, but let us say the regulatory environment, the independence of the people tasked with the verification of the compliance with such regulations and the average safety standards I’ve seen widely extended and tolerated in such societies (I’ve lived in the three countries) do not help to assuage my concerns about the risks that such complex installations may end up causing in their laxly regulated communities. But what is the alternative, then? For most of the years that such plants have been operating the only real possibility for producing the amounts of energy demanded by their economies (that aspired to grow as much, if not more, than anybody else’s) would have required burning vast amounts of fossil fuels, as wind and solar where costly toys with an extravagant price tag, and hydro was already being used to the hilt (and had its own environmental problems). Even today, when the price of (especially) solar has decreased very substantially, given the problems associated with its intermittence and lack of scalable means of storage in the right price bracket it is not feasible to just shut them down and hope the economy will keep on chugging along (economies, in most cases, heavily dependent on the export sector in cutthroat competition markets, which can not afford the luxury of seeing their energy costs go up a 20-30% as the Germans did after cavalierly closing eight of their seventeen nuclear plants –you know, the risk of a Tsunami going from the Baltic coast to Neckar-Westheim or Biblis, only more than 500 km inland in a seismically stable location, was just too big). But that was the old me thinking, the one that still believed that all our efforts could be enough, that the risks were indeed as low as our calculations showed them to be.

However, the new me, the one that had seen the concatenation of unlikely events unfold (and, a posteriori, reveal themselves to be not only not that unlikely to begin with, but all too predictable) to finally result in the unthinkable turning into the unavoidable, was not so sure. If there is an existential risk to sizable chunks of the population, no economic gain can justify subjecting those chunks to it. Of course, the lessons of Fukushima were learned, and promptly applied. Our older 2nd generation reactors (designed in the 50’s, let’s not forget!) have been made safer, with diesel fuel deposits moved to higher locations, non subject to flooding; new fast coupling connections have been installed so the safety-critical systems can be fed with batteries even in the (now even more unlikely) event of lack of fuel, and adequate arrays of batteries have been safely stocked; new contention filtered ventilation systems are still being installed, that would allow to reduce a potentially dangerous build up in pressure within contention by relieving that pressure through HEPA filters (that would retain the radioactive particles, avoiding dumping them in the atmosphere), thus making a succession of events like the one that ended in the explosions (and breach of all the defense barriers) all but impossible. Of course, with all those design modifications, imposed by the regulators in all the countries where BWR reactors still function, the price tag of nuclear energy has kept creeping up (for critical minds, skyrocketing offers a better description of the phenomenon than the milder “creeping up”), which makes the whole proposition even more dubious (no kidding the British are having second thoughts about Hinkley Point and their other chosen locations).         

I really don’t know, and part of the purpose of this long confessional was to clarify my own position (something I’m afraid I’ve failed miserably at). I still tend towards seeing a strong role for conventional (i.e. fission) nuclear energy in humanity’s energy mix. As a species we need to master not only “environmentally friendly” sources (solar, wind, hydro, tides, geothermal, although much could be said about how environmentally friendly some of them really are, and how their true costs keep being whitewashed by the media and the clueless “ecological” movements that tirelessly promote them), but some “dense”, “hot” and yes, potentially dirty, sources as well. As only half-jokingly I once said to a friend, our descendants, sooner or later, will leave this lump of rock and claim their place between the stars. And sure as hell it is not going to be solar and wind which propel them there. Who knows, may be they even find some other civilization in their never ending quest (which is the natural continuation of our own never ending quest, btw), and when that happens, I hope it is our descendants the ones that can deploy the hottest, densest (and yes again, probably dirtier) energy to stand their ground. I just think we have to be more humble about it, and to better understand the very real, very valid concerns of those that don’t have such lofty aspirations for humanity. And keep working hard, each one of us in the station he has been assigned (or the one he has chosen), to assuage those concerns and make sure, as much as it is within our reach, that the particular type of energy we have devoted so much of our professional lives to further is indeed as safe and as clean as our equations and our models purport it to be.  

As a side note, I think our collective failure to achieve perfect safety (even in the face of one of the most destructive earthquakes history has ever recorded) in spite of the enormous amounts of effort devoted to it (in terms both of time of very skilled, very competent, and very expensively trained professionals, and of material safeguards that also come at considerable expense) also has something to teach us about why technology seems to have stagnated. We are so conscious of the risks, we understand so deeply everything that can go wrong, we have developed such comprehensive models, that allow us to forecast in such minute detail everything that can happen in response to the most minimal perturbation that we literally drown in documentation, become victims of the dreaded “paralysis by analysis” and lose sight of the forest for the trees. And in the end I’m not even sure we don’t end up missing the real risks (in this case, a much higher tsunami than what we had prepared for) being lulled in a false security by all the too-distant, highly unlikely ones that we have identified and mitigated…
But pursuing that line of thought (the negative impact of over regulation and a culture of quality “assurance” that puts impossibly high burdens in the development of any true innovation) would take us too far from the modest goals I had set to myself in this confessional, and would thus need to wait for a separate post.

No comments:

Post a Comment