wonder in amazement how a chernobyl or fukushima isn't happening every year.
Comparing Fukushima and Chernobyl is like comparing apples and turds. The debacle at Fukushima had nothing to do with the reactor design; it was due to the braindead siting of the backup diesel generators and their switchgear behind a seawall that got overrun by the tsunami. The reactor design itself was fine, and in fact has withstood loss of coolant conditions that, by any reasonable prior expectation, should have caused much more radiation release than they did.
Chernobyl, on the other hand, had:
* No secondary containment;
* A Soviet-run staff that thought running badly controlled experiments at high power levels was just dandy;
* A graphite moderator that ignited when exposed to air.
Fukushima is not even in the same league from that perspective.
That type of nuclear power generation really is that terrible.
This is a serious overstatement. Many reactors designed along the same general lines have delivered decades of power with no problems. (Not to mention that the US Navy has run reactors of similar design on its ships for decades with no problems.) I'm all for improving reactor designs, but I also think there are existing designs that could have gotten plenty more use without significant added risk. The fact that we haven't done that is a bug, not a feature.
Yeah but the notion that you can have a power plant which requires outside power in order to not melt-down is -- frankly -- retarded.
Imagine a coal plant that burns down 100,000 acres around it if the primary coal containment system (made up) loses power. Would anyone like that in their backyard?
Or a hydro plant that if power isn't continuously supplied to, not only could the dam breach and flood downhill but also somehow miraculously uphill too (not realistic but comparative to nukes).
That's what a nuclear power plant that can't slowly coast to a stop is like. I don't care how many backups and backups of backups you have, if physics isn't on your side if/when the plant loses power it's a horrible design.
the notion that you can have a power plant which requires outside power in order to not melt-down is -- frankly -- retarded
You're right that this is an additional risk factor, which would be eliminated in a design that required only passive cooling after shutdown (and newer designs have this feature).
But "retarded" is too strong. Just having the backup generators not come on for a short time period isn't enough; they have to be unavailable for days or weeks, as the Fukushima ones were. Also, the switchgear has to be such that portable generators can't be brought in and hooked up. I was extremely surprised to find that all of those design decisions were apparently made wrong in the Fukushima plant.
And even then, when put in proper perspective, the negative consequences of nuclear power are less severe, when averaged over all the kilowatt-hours of power produced by nuclear plants, than the negative consequences of other forms of energy. Coal causes far more mortality and morbidity per unit of energy generated, for example. It's not "retarded" to choose a power source that has less severe side effects all things considered.
Again, that's not to say that reactor designs should not be improved. But by any reasonable standard, nuclear power even with existing designs is safer, all things considered, than other major forms of energy. The only reason the public does not understand that is that "radiation" is a buzz word, whereas "respiratory failure due to coal dust", for example, is not. (And even "radiation" is not used fairly; coal ash has higher levels of radioactivity than many forms of nuclear waste. But the public isn't exhorted to protest about radiation from coal ash.)
I agree that average over the kilowatt-hours nuclear might be safer than coal. But the problem is that the risk is HIGHLY concentrated.
I can self-insure my computers because if one ever fails I have the cash to handle it. It's not a financial crisis. I don't self insure my car (for collision/comprehensive) because it's too big of an expense for me to absorb at any one time without severe hardship.
Nuclear reactors (as they stand today) are more like cars than computers. They tend to rob a few people of their whole lives and really eff up the ones that don't die. Coal plants have the "advantage" of robbing many people of a portion of their lives in a more subtle way.
LFTR reactors have physics on their side in that if containment is lost, so is criticality. Boiling water reactors, pressurized boiling water reactors, etc in my mind can't be made safe because they require power to stay safe, even if they're not generating power.
You've suggested that so long as the generators and whatnot arrive eventually, things will be fine. The problem is that you've made the assumption that somehow, some way the generators will arrive and the reactor can be made safe again over the course of some weeks or months. Nuclear reactors are one of the few pieces of infrastructure that can't simply be abandoned if something bad happens, or else the problem gets worse and worse and worse. This is a positive feedback cycle rather than a negative one. Positive feedback often "blows up" (a term we use in electrical engineering) or grows without bound. Nearly everything else in modern society functions with negative feedback and that kind of intrinsic safety is what most people want.
That's not to say that ALL nuclear reactors are by definition unsafe; just all the ones that are currently operating commercially because it's such a nightmare to permit new designs and the existing manufacturers have no interest in inviting competitors into their market.
LFTR reactors have physics on their side in that if containment is lost, so is criticality.
But loss of criticality isn't sufficient for the reactor to be "safe". Even with the reactor no longer critical, there are still a lot of radioactive fission products left. The way to prevent them from escaping is secondary containment, which Chernobyl did not have, as I said (Fukushima, and indeed every other reactor ever built that wasn't built by the Soviet Union, has secondary containment).
Of course, as Fukushima illustrated, secondary containment is not the only necessary feature for safety. You also need decay heat cooling. The key advantage of a design like LFTR, as compared to a design like Fukushima, is passive decay heat cooling; simple thermodynamics is sufficient to keep the fission products contained and cooled after shutdown. That's why such reactors don't, in your words, "require power to stay safe, even if they're not generating power". However, LFTR is not the only possible design with passive decay heat cooling; there are ordinary pressurized water reactor designs that have passive decay heat cooling (by designing the piping circuits and placing the heat exchangers and core to take advantage of natural convection). Fukushima was not such a design, but they do exist (although AFAIK they didn't when Fukushima was built).
Nuclear reactors are one of the few pieces of infrastructure that can't simply be abandoned if something bad happens, or else the problem gets worse and worse and worse.
This is true, but it's just as true of passively cooled designs like LFTR. The problem here is what to do with the highly radioactive fission products. The way every nuclear-using country except the US deals with this is reprocessing: you take the spent fuel, separate out what's still fissionable (which is a pretty large fraction of it with most current designs), and put what remains through a special reactor that converts the fission products to either much longer-lived (and hence much less radioactive) or stable isotopes. Problem solved. France and Japan have been doing this at scale for several decades now. The only reason the US doesn't is politics.
A loss of criticality ensures that you don't end up with a positive feedback cycle that lets the problem spiral out of control faster than you can react, and possibly faster than you can comprehend.
A pressurized water reactor relies on the pressure vessel not being breached in order for the passive decay cooling to work, if that happens we're right back to Fukushima/Chernobyl style problems.
I am talking about short-term "everyone evacuate the building" types of disaster scenarios. You can do precisely that with a LFTR because of the passive decay heat cooling combined with the loss of criticality that happens when the freeze plug melts.
On a longer term the fission products might be a problem with an abandoned LFTR but because of the loss of criticality and the passive decay it's 100% acceptable to just wait for everything to cool down, fix the problem and restart. Or if things are so broken you can't fix them at least you don't have to keep putting people in harm's way to try and prevent a wider-scale disaster. Once things have cooled you go collect the nuclear material and send it to another plant to be used.
The best way for me to explain this is with analogies using potential energy.
1. The nuclear power plants we have now are a big heavy rock precariously balanced on top of a fairly narrow peak. Small movements to one side or the other can be recovered from but at some point that rock has started to move and will move aggressively. It will eventually reach the bottom of the hill but not before crushing everything in its path. We don't really even know how bad the damage can get.
2. A LFTR is like a big heavy rock perched about 10 feet up a shallow hill. It requires some energy to keep it there or else it'll roll down hill. You can't really push it up further so it's safe from disturbances in that direction. If you push it down hill (or cease holding it up) it only rolls 10 feet before it naturally hits the bottom and comes to a stop.
The majority of the things in the world act more like 2 than 1 and thus we aren't terribly scared of them. Yes there are a great many things you can do to ensure that 1 doesn't get away from you, but ultimately you're still fighting gravity.
Let me reiterate, I'm not against nuclear power. I just REALLY don't like the idea of the balancing act that has to be performed in 1 and far prefer the kind of intrinsic safety that you get from 2. I'm all for building plants like 2 even if they're not LFTR based. I don't have religion about the form, I just want as much safety as I can get.
A pressurized water reactor relies on the pressure vessel not being breached in order for the passive decay cooling to work, if that happens we're right back to Fukushima/Chernobyl style problems.
AFAIK the pressure vessel was never breached at Fukushima. They had plenty of problems whose primary cause was the absence of cooling water (including a hydrogen gas explosion), but there was never an uncontrolled criticality because of it. (Also see further comments below on criticality.)
I am talking about short-term "everyone evacuate the building" types of disaster scenarios. You can do precisely that with a LFTR because of the passive decay heat cooling combined with the loss of criticality that happens when the freeze plug melts.
Ok, this makes it clearer where you are coming from. I certainly agree that the LFTR is a big improvement over the standard PWR design.
We don't really even know how bad the damage can get.
It's true that Chernobyl could have been worse, so we can't really judge the worst case from what happened there. However, these worst-case scenarios have been simulated in great detail; the physics is actually pretty simple.
With any design that isn't Soviet-built, a loss of coolant will not cause an uncontrolled criticality; losing coolant decreases the reaction rate, causing loss of criticality. The problem with the Chernobyl design was that it had a "positive void coefficient of reactivity", meaning that the reaction rate increased on loss of coolant. That feature, as I said, is not present in any non-Soviet design, which means it's not present in any commercial design currently operating (since all the old Soviet reactors have been shut down).
I just REALLY don't like the idea of the balancing act that has to be performed in 1 and far prefer the kind of intrinsic safety that you get from 2.
So do I. Now that we have such designs, we should certainly be building them, and should not be building the old designs that lack those passive safety features.
Yes that's true that there was never uncontrolled criticality. But that's because people were in there restoring some way to get water into the cores. Had that not happened, they likely would have melted down. Once all the water boils the heat doesn't have anywhere to go so temperatures go up. If that happened that's a melt-down and the core liquefies and then may or may not have been stopped by the containment shell. http://www.nbcnews.com/science/if-theres-meltdown-then-what-...
In my mind the worst-case scenario is that the core melts, the containment shell is cracked and the whole mess goes through the floor and into the ground. Has that been simulated at all? I'd love to read a paper if it has. I haven't seen anything with a cursory search.
Yeah, absolutely. We need reactor designs that don't melt down when they fail and lose power. LFTR and perhaps pebble-bed reactors would be far safer than what we have now, and safer than coal in many ways.
Unfortunately, it's complicated to explain that to people. People don't really want anything to do with nuclear after all the issues of the past, and it's hard to blame them. Nuclear really needs a rebranding and safer designs.
Some common sense would help too. We should shut down nuclear power plants that are on earthquake faultlines.
This is a positive feedback cycle rather than a negative one.
It occurred to me on re-reading that you might have been referring here to the fact that the Chernobyl reactor had a number of features that acted to increase rather than decrease reactor power as actions were taken to try to shut it down. Those features are not present in any current reactor designs that weren't made by the Soviet Union. Certainly they were not present in the Fukushima reactors.
I was more referring to the idea that once you lose the ability to pump coolant, the reactor starts to heat up. Then as it heats up, it starts to melt itself. As it melts, it re-attains criticality and begins to generate more heat, which leads to more melting, which leads to more heat, ad nauseum.
We don't really even know when this stops or how it stops or whatever because the only time (so far) that it really started to get away from us (Chernobyl) a bunch of brave men gave their lives and dumped boron straight on the exposed reactor core to stop it. By doing so they spared us from gaining the very painful knowledge of how a meltdown ends naturally, at what point an equilibrium is reached.
once you lose the ability to pump coolant, the reactor starts to heat up. Then as it heats up, it starts to melt itself. As it melts, it re-attains criticality
If it's the Chernobyl design, yes. Not otherwise. See my comments upthread in response to another of your posts. The Chernobyl design had particular features that are not present in any currently operating commercial reactor.
The problems at Fukushima had to do with design and siting of the overall plant, which is, in fact, very much an element of engineering. Truth is, there are lots of ways for a nuke to fail, and the small comfort that Fukushima didn't fail in the same way Chernobyl did doesn't make Fukushima any less of a failure.
The Japanese have also exhibited some spectacularly poor nuclear management in the past (a criticality incident in fuel handling at Tokaimura: https://en.wikipedia.org/wiki/Tokaimura_nuclear_accident) and significant involvement by the Japanese mafia in TEPCO). In fact many or most nuclear incidents anywhere can be chalked up to poor management -- it's a major risk factor.
As for the US Navy, the man who made that happen argued strongly against nuclear power. US Navy Rear Admiral Hyman Rickover:
I do not believe that nuclear power is worth it if it creates radiation. Then you might ask me why do I have nuclear powered ships. That is a necessary evil. I would sink them all. I am not proud of the part I played in it. I did it because it was necessary for the safety of this country. (see full quote and others at Wikipedia: https://en.wikipedia.org/wiki/Hyman_G._Rickover#Willingness_...)
Rickover also explicitly noted that the US Navy's safety was the result of a total philosophy and approach, not a solution which could be ladled or patched on to other systems.
This is true of any field in which, in the words of Feynman in his report on the Challenger disaster, "reality must take precedence over public relations, for nature cannot be fooled".
the man who made that happen argued strongly against nuclear power.
As the Rickover quote you give shows, Rickover thought of "radiation" as having magical powers, like many members of the uninformed public. His arguments on such grounds are not cogent. (Another quote in the Wiki article shows that Rickover also disliked nuclear power because of its relationship to nuclear weapons, which is more reasonable, although still not sufficient to justify getting rid of nuclear power IMO.)
His comments on the US Navy's particular philosophy, which worked for a military organization but would not work for civilian power companies, are valid as far as they go. However, to me that's a bug, not a feature. To see why, consider the following sketch of an alternate history: in the mid-1970's, having realized that OPEC is not going to play nice any more and therefore foreign oil is not a good basis on which to run the US economy, the US government makes nuclear power a national priority on national security grounds (much as France did). Knowing that existing reactor designs require skilled operators and strict procedures to ensure safety, the government institutes licensing similar to what is done with professionals in various fields, such as engineers, whose activities can, if done incorrectly, pose significant risk to the public. The US Navy program is used as a model, but the military-style aspects of it are adjusted to something more appropriate for a commercial endeavor.
Result: in the alternate 2014, the US imports no oil (except possibly from Canada), the majority of base load electricity comes from nuclear power plants, coal mines are all shut down and their sites cleaned up to serve as ski resorts, offshore oil drilling is a thing of the past (so no Deepwater Horizon spill), and the US can just leave the Middle East alone (so no special treatment of Saudi Arabia, probably no 9/11, no invasion of Iraq).
There are some technologies which are inherently riskier than others. A solar meltdown or wind fuel spill isn't going to risk tens of thousands to hundreds of millions as a nuke plant incident could.
[Rickover's] arguments on such grounds are not cogent.
Y'know, blithely saying that of someone who spent 35 years in the nuclear industry, pretty much creating it, shows ... a certain hubris. I'm unpersuaded by your argument.
Your nuclear alternative universe omits the one glaring limitation of conventional nuclear: there's not enough fissible material to run nukes for more than a few decades, and much less than that if the fraction of energy produced from nuclear is increased. The alternatives are breeders (weapons, proliferation, and processing risks) or thorium MSR (MOX designs don't achieve the fuel utilization rates necessary to achieve a long-term sustainable energy source status). Thorium MSR suffers from the slight limitation that some 40 years after initial and very preliminary exploration, it's still at least 25 years from commercial deployment -- by the assessment of the usually optimistic Chinese: http://www.reddit.com/r/dredmorbius/comments/1uy239/energy_c...
I'll omit the other glaring omission: that oil provides fuel for transport, while nuclear doesn't. Synthesis of transportation fuels is a challenge of engineering, complexity, and scale.
Rickover actually addressed aspects of this in a 1956 speech:
I'd recommend reading it in full (he articulates and builds his argument well), but:
For it is an unpleasant fact that according to our best estimates, total fossil fuel reserves recoverable at not over twice today's unit cost, are likely to run out at some time between the years 2000 and 2050, if present standards of living and population growth rates are taken into account. Oil and natural gas will disappear first, coal last. There will be coal left in the earth, of course. But it will be so difficult to mine that energy costs would rise to economically intolerable heights, so that it would then become necessary either to discover new energy sources or to lower standards of living drastically.
Huh? No nuclear plant incident has even come close to this level of impact; this number is at least four orders of magnitude too large, and quite possibly more.
someone who spent 35 years in the nuclear industry
I didn't say all his arguments weren't cogent, just the particular argument he made about "releasing radiation".
there's not enough fissible material to run nukes for more than a few decades
Sure there is, if you reprocess the spent fuel (spent fuel actually still has a fairly large fraction of fissile material in it) and/or run breeders (sure, you have to keep control of the nuclear material, but that's a lot cheaper than the alternative of making us all poor because we don't have enough energy).
I was surprised to see the Chinese that pessimistic about the time scale for thorium reactors; I haven't had time to dig into the details to see what the roadblock is. They're not the only ones working on those, either.
oil provides fuel for transport, while nuclear doesn't.
But oil provides fuel for other things besides transport as well. If it only had to provide fuel for transport, that would change things significantly.
(Also, battery technology is a lot better now than when Rickover made his speech; electric cars can now actually have decent range for things like commuting.)
Rickover actually addressed aspects of this in a 1956 speech
Yes, I've read it. One thing that struck me was that he came right out and said that energy == standard of living, which is true, but it's an inconvenient truth. Of course, he wasn't a politician.
Self-followup: Global Warming was in fact a thing by 1956. In fact, noted as early as 1932 (with earlier work on CO2 as a greenhouse gas dating to the 19th century):
The real difference between Chernobyl and Fukushima are the earthquake and tsunami which killed tens of thousands and leveled much more infrastructure. Fukushima makes for a very poor counterpoint to nuclear energy; the nuclear accident pales in comparison to the real disaster.
Neither were failsafe. Where failsafes existed, they were disabled.
What failsafes were deliberately disabled at Fukushima?
Yet. The externalities are brutal.
So are the externalities from coal mining and oil drilling. They just have a much more diffuse impact, so nobody complains. Per unit of energy delivered, nuclear has much less impact.
Fukushima's shield wall failed. Pretty much the opposite of failsafe.
Anticipating your continued argumentative retorts in your spirited defense of nukes, it's also well known (documented) that this was an identified risk, and that other reactors along the coast did have sufficiently high shield walls.
You've omitted stockpiling reactive waste from your calculus. Ditto the inadvertent release of contamination.
A small tip: If you're pro nuke, you may want to advocate traveling wave reactors. Treehuggers like me are looking for solutions, not more rhetoric.
You mean the seawall that was protecting the switchgear for the backup diesel generators? That didn't fail; it was simply not high enough to keep out the tsunami. Which, as you note, was not the case for other similar reactors:
it's also well known (documented) that this was an identified risk, and that other reactors along the coast did have sufficiently high shield walls.
Agreed. Which shows that reactor designs of that generation can be operated safely. See below.
You've omitted stockpiling reactive waste from your calculus.
Which is a lot easier if you reprocess the spent fuel, as every nuclear-using country except the US does (US policy forbade it from the mid-1970's until about 2000, since then there have been, IIRC, contractual issues getting it started).
Ditto the inadvertent release of contamination.
Which, once again, is much smaller than other major energy sources when evaluated per unit of energy produced.
Treehuggers like me are looking for solutions, not more rhetoric.
And once again, of all the other major energy sources--by "major" I mean "capable of sustaining the required base load capacity for a country the size of the US at first world standards of living"--nuclear is by far the safest. What opposition to nuclear power by treehuggers like yourself has done is to force people to make a choice: either drastically reduce our standard of living, or use energy sources with much greater health and environmental impacts like coal and oil. Guess which choice people picked?
I completely agree that, now that we have safer nuclear reactor designs, we should be building them, and not building any more of the older, less safe designs. (I don't know that traveling wave reactors are at the point where we can build operating plants, btw; but there are other inherently safe designs that are further along.) But given that we have plenty of existing plants that are perfectly capable of being operated safely, we can get cleaner energy from them than we can from coal and oil.
1) buy perrows book "normal accidents"
2) read the nuclear accident chapters
3) begin marching in the streets at the sign of any new old-style nuclear plants, or the continued operation of the existing ones.
optional:
4) wonder in amazement how a chernobyl or fukushima isn't happening every year. That type of nuclear power generation really is that terrible.
(note - I am actually pro-nuclear-power ... just not the way we do it now)