This is probably a good time to recap what we know about the risks nuclear energy, now that the serious problems caused by the nuclear accident at the plant Fukishima in Japan are about to go into the background. Not because the problems in Japan are no longer serious, but because sound the drums of war for Libya and the whole focus of our attention has shifted there - Spain, who care a 13.4% of its vital oil consumption in this country and not find it anywhere, was quick to join the military effort of this campaign. In addition, advocates nuclear energy option were suffering too much punishment these days attempt to justify their position and it is quite fitting that we forget a little bit of Japan and the disaster. With the restoration, at least in part, the power plant in Fukushima cooling pumps return to work unless they are severely damaged, and in a few days the situation will be "under control" (although some vessels damaged reactor and have released and released some radioactive material). Time seems to play now in favor of a resolution with limited damage, and therefore the time of the debate in the media on the nuclear option is complete. However, this sudden debate will have a strong influence on the development of the Oil Crash : many countries have lengthened or deadlines for implementation of new plants and some old ones have closed, in addition, Japan needs to urgently desperately to recover electrical power. All this means increasing global consumption of oil, gas and coal, but as we know, oil peaked in 2006, the coal in 2011 and gas arrive in 2025, while in Europe will be felt from 2015, if not accelerated by increasing their consumption and that despite the "good news" of shale gas, which these days is haunting Europe . Although uranium is not much better, with a likely peak in 2015 ... We are at a transition point in regard to our viability as a society that needs to consume many resources to continue: we are about to embark on the first war of the resources of a new era of energy scarcity, but the accumulated contradictions above and the difficult balance between various factors, unstabilized food riots in many countries in the world and catastrophic events such as Japan that just having a global impact and can accelerate the degradation process. We are dominated by nonlinear effects, where a small change can be amplified greatly, and the only security we have is that the decrease of right side of the Hubbert curve be steeper than predicted by theory .
I am in favor of discussing the risks of nuclear power from the serenity and cool analysis, and that society, with all the data in hand, decide if it worth taking that risk or not, knowing well what it means to abandon nuclear energy. To clarify these issues will outline all the risks of nuclear energy, I am not an expert and topics that I will require a very deep discussion which I think corresponds to other face it honestly and without focus to defend their interests shortsighted.
The first thing to understand is that when it comes to risk are two factors that according to game theory it up. The first is the probability of adverse event and the second is the impact of this event. In discussions of these days, lawyers for the nuclear energy much affect on the first factor (it is highly unlikely a serious accident, nuclear plants are planned to monitor everything that is expected) while opponents emphasize the severity of impact (A serious accident contaminated means leaving a large expanse of land and turn it into dead land where no one can live for millennia). The street people tilts between two feelings: first that of the unpredictability of something to happen, and on the other the fear that if that "something" happens to be the end. But given the benefits that plants provide us (if you look coldly just other power source) the public opts for inaction and leave the matter in the hands of experts in charge. And these experts, whose salary depends on the continuity of this business, they have the right incentives to be objective.
Needless to say that the analysis I shall now I focus on technology we are applying to commercial scale today, which is based on uranium, on those famous reactors operating with plutonium and thorium (which although it seems that just discovered 50 years ago that is experienced with them) and maybe we'll talk another day, clearly in another context (that of its viability, as already discussed for the case of nuclear fusion ). Finally, in what follows, I will discuss briefly the various stages of the process necessary to operate nuclear power and give a subjective assessment of the two parameters of the problem: impact of the most serious accident that may occur and probability that such accidents can occur on the scale of a human life.
- Mining: The natural uranium extraction activities have a significant environmental impact. Most of the uranium mineral deposits in the world have a concentration very low, since the distribution of the wealth of ore (usable mineral percentage in relation to the rock where it is) follows a log-normal distribution , which most uranium stocks have a low concentration ( estimated that the concentration limit to be energetically profitable to extract the uranium is 0.02% for hard rock and 0.01% for soft, but details The Lean Guide to Nuclear Energy ). This implies that to obtain uranium in most places you have to do for leaching (leaching English) technique which consists in filtering acid through the rock to go removing the oxides in its path, including uranium oxide. There are two ways of applying the leaching uranium, or taken out of the rock, make a stack and applies the acid (leaching of cell), or acid leaks on the ground and collecting the resulting fluid in a pipe at the bottom (in situ leaching). Leaching stack is supported only in countries with lax environmental regulation as it involves creating large pools of waste residues (similar to the infamous Boliden in Spain ). These rafts are highly polluting due to the presence of heavy metals and character very acidic, and contain traces of radioactivity of uranium extracted. In addition, these ponds are rarely treated, and would require a lot of money and add much energy, and the activity would become meaningless, usually they are left to dry in the sun for years and are covering it with mud to prevent dust heavy metals is carried by the wind. As for the in situ leaching can only be done if the substrate is porous and also implies a risk of seepage into the aquifer. U.S. the in situ leaching is the only technique currently permitted for mining of uranium, according to the Geological and Mining Service of that country. It must be said that due to exhaustion of the richest mines, most metals mining continues today these techniques, so that the risks of uranium mining are not unique to it.
- Impact: Medium to high . The toxic ponds can cause serious accidents such as a few months ago in Hungary (which was not uranium mining should clarify) and its influence is very harmful to the environment and people in the neighborhood (not just workers; affected a few kilometers around the facility), by the dragging of heavy metals by the wind.
- Chance: 100%. Rafts stranded (as is the usual practice) slowly pollute the environment, and sometimes heavy rainfall events and erosion create catastrophic events.
- Enrichment To use natural uranium at a nuclear plant, it is necessary to increase the relative concentration of isotope atomic mass 235 (U-235), more rarely, on the dominant mass atom 238 (U-238). To do so is subjected to a repeated series of processes that will increase the proportion of U-235 from the 0.7% found in nature to the 4-5% used in reactors. There are various techniques to achieve this enrichment, but the most used today (because of its better energy efficiency) is the spin of a gaseous compound of uranium, uranium hexafluoride (UF6). After separating the enriched sample, there are large amounts of residual uranium hexafluoride, depleted, which also have nuclear waste category because they are still radioactive. The great problem of uranium hexafluoride, except that is toxic and corrosive, it is very unstable and reacts explosively with water, even if the ambient humidity is high. The UF6 accidents are frequent , And storage is a serious problem because it is difficult to ensure its containment indefinitely.
- Impact: Alto. Although leaks are usually self UF6 (a product of decomposition is a solid that tends to plug the hole), a string of small explosions could break the container, causing a large explosion, spreading over a wide area of \u200b\u200bmaterial toxic and radioactive. Underground storage of this waste is counterproductive, since even the salt mines, which should be free of water leaks are important, as evidenced by the fiasco of Yucca Mountain nuclear storage in the U.S. or the Asse II in Germany (which is a real bomb), and the waste could seep into the aquifer and contaminate the water supply of large areas.
- Probability: Very high .
- Central Nuclear This is the only issue that was discussed during these days, which has focused all discussions. According to nuclear engineers, the risks are minimal for the low probability of catastrophic events, and when they occur is by the negligence of those operating these plants. This dissociation between the technical factor (on paper, in practice things do not go as planned) and the human factor is a little child: you have to consider the real-world problems with real constraints, and often designs are no worse than projected for the inability of the technicians but by the need to save costs, as Yuri Andreyev complaint in a recent interview La Vanguardia, the need to reduce costs for nuclear plants are economically viable leads a reduction, possibly intolerable security. In any case, the major problem is that the impact of a catastrophic event is extremely high: in the worst case scenario, the reactor core would melt and all the contentions would break, which would be exposed to the environment enormous quantities of highly radioactive material that the wind and rain disperse and would establish quickly. The radiation level near the exposed area would be so high that it makes it impossible for anyone near, so to clean the molten core and / or repair the crack should use robots, which implies a slower in the work and greater dispersion of heavy radioactive contaminants. It should be noted that trace amounts of heavy elements (the famous "radioactive particles") can cause serious health damage of the people who absorb, with the highest incidence of cancers and other health problems during their lifetime, these particles can travel hundreds of miles, even thousands, driven by wind. For this reason, if the damage to the containment of any of the core is too large Japanese reactors may be opting to build a concrete sarcophagus of Chernobyl-style "to prevent the rapid spread of the particles, and that endorse as a serious problem to future generations, when the concrete structure weakens in a couple of centuries, they will be faced with fewer resources and energy available.
- Impact: Very high with damage that takes thousands of years removed and unprecedented lethality.
- Chance: the words of the proponents of this energy, very low. If I judge by my own life (40 years) I lived three: the Three Mile Island that of Chernobyl and the Fukushima, although the impact of the first was small, the second was high and on the third yet to be determined. The logical probability grows with the number of reactors in service and their age, and that number has increased rapidly worldwide since TMI so far.
- Proliferation: devices uranium enrichment can be used to enrich the material to the concentration of U-235 atomic bomb itself (80%) have there-at least theoretically, the risk that Iran has uranium enrichment plants. However, states are less likely to use this material in a war over principle Mutually Assured Destruction (MAD in English, like crazy). One difference is that extremist and radical groups decide to use material they can get in the market black, or even nuclear waste from a cemetery to make a dirty bomb , even home.
- Impact: Very high .
- Chance: very high, in my view: we are in a world that walks into the Oil Crash preparation and energy descent, where the many injustices foster the desire for revenge of the disinherited land.
- waste storage: This point was discussed in a previous post, " Cemeteries nuclear and other .
- Impact: Very high . Some authors argue that the inability of management of cemeteries nuclear exterminate life on Earth in the coming centuries.
- Chance: 100%. There are many cemeteries and countless nuclear waste stored at nuclear power facilities, and at least some will end up being exposed, especially if one considers that require maintenance energy and expertise and both are scarce.
- depletion of uranium: We have already discussed in a post above, "Peak uranium ." In the coming years (25 at most, and 5 in the worst case) reach the zenith of uranium mining, and from that moment miss uranium for power plants, and growing.
- Impact: High . What about plants? Decommissioning costs are prohibitive, and our confidence in this source of energy puts us in a situation of social and economic vulnerability (although that is no different with respect to our dependence oil, gas and coal).
- Chance: 100%.
I have not discussed here other risky activity, the reprocessing, because I have almost no data on it, but all indications are that it is very dangerous.
For conclude, if you look at the list of risks of all nuclear activity, considering not only the observed or expected probability (which is not so low after all) but the impacts, taking into account not only its spatial extent but temporary, the obvious conclusion is that the risks of energy nuclear is not far from negligible. Indeed, the best way to combat these risks (except the last) is to invest money and efforts to mitigate extreme acceptable, although this implies a cost overrun on the already discussed economic capacity of this energy. The big question is how we will meet these expenses if, despite we nourish the bodies of those who fall , more will be poorer because this economic crisis will never end ...
Salu2,
AMT
P. Data: During the next week I'll be out of Spain, so I can not follow the blog. Since the blogger spam filter blocks somewhat randomly Some comments not be alarmed if your comments are disappearing, and I manually publish it as soon as possible, not repeating the same message several times because it reaffirms the filter ...
cleave but not killed.
Addenda (April 13, 2011): An interesting French documentary on nuclear waste in RTVE to the letter. essential
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