So I'm sure most of you will have seen the video of the explosion at the Japanese nuclear facility damaged during the earthquake and Tusnami yesterday. As soon as I saw it I was pretty sure I knew what had happened. It appears to be a catastrophic failure of the containment building due to the increased pressure within the dome being suddenly pushed beyond failure point when hydrogen ignited inside containment. What is worse is that the source of the hydrogen build up is most likely from the following. First the core became partially uncovered/dry (dry is relative as it would still be bathed in high-quality steam). This portion of the core eventually exceeded 1200 C and the cladding began to chemically change from zircalloy to a partially a compound of zirconium and fuel rod material. Zirconium and steam at that temperature can have a self sustaining exothermic reaction that produces hydrogen gas. Large portions of the uncovered section of the cladding in the core would be quickly converted to brittle residue and an aerosolized mixture of hydrogen and particles of cladding, fuel, and lattice. Since pressure vessels are quite tough this would not necessarily compromise its thick steel walls. The pressure inside it would also be prevented from reaching dangerous levels by emergency valves which are venting into the containment building (which was already compromised.) Under less catastrophic conditions, electric fans and other systems would circulate air inside containment to prevent hydrogen build up/bubble formation and sprayers would be helping to keep pressure down. These systems have failed however as emergency backup power was down, external grid power was lost, and the sprayers finite supply of gravity fed water would have run dry. From the video it appears the hydrogen bubble and aerosolized corium mixture ignited and partially collapsed the containment building. This is pretty bad- it's what they were worried could happen but did not at three mile island. It is not a hot nor energetic enough explosion to produce the plume seen at chernobyl but it is certainly bad. By the time people read this my guess at what happened from watching 12 seconds of video showing the explosion might turn out to be far worse than reality. I hope that is the case, but it really looks as bad as I think it is. Anyways - this had me thinking about the portion of our nuclear plants located on fault zones. Some of those plants have a similar over-reliance on active safety systems and could suffer similar problems during supper-massive earthquakes. Why do we not have a firm commitment to phase out older plants in fault zones as we gradually build newer passively-safe plants in seismically stable locations AND to upgrade the grid to make the increased distance of transmission economical? I mean even a very long-term and very conservative time-line would be better than what we have - defacto perpetual use of obsolete designs in fault zones.Actually I find our lack of a long term roadmap to modernize and improve our nuclear power systems and close (as much as possible) our fuel cycle to be frustrating. I know we won't fix it all overnight, but we do posess the technology and plant designs to build passively safe plants which can be built less expensively than the previous generation, run more efficiently, and safely weather catastrophic accident conditions for 3 or more days without operator action. We also have the technology to help close our fuel cycle (reduces end waste volume and longevity) significantly now but it's illegal to do so - even if done in ways that do not produce weapons grade material. Adittionally we are developing particle beam spalation technology (as is the EU) that can be used potentially to safely transmute waste and produce enough electrical power to pay for itself in the process. Why do we not at least have a firm commitment to move towards these things, even if very gradually.
3/12/2011 6:09:23 AM
NIMBY and promotion of alternative energies from the environmental left is why we have no forward motion to speak of on nuclear power production. Their pie in the sky notion that we can power the entire world on solar/wind plants with natural gas as a fallback is ridiculous.And it sounds like TEPCO has had issues with falsifying safety reports at their nuclear plants. The CEO had to resign in 2002 over this. God only knows what they have gotten away with. You would think as a country that had two atomic bombs exploded over it, they would appreciate the danger of radiation and be more safety conscious.Bottom line this is terrible for the nuclear industry. If people really want to save the world and go green with the electric grid, the baseload must be handled by nuclear fission until fusion reactors are able to takeover at some point in the future. Fission is the only reliable way to generate large amounts of electricity constantly and with no carbon footprint. Obviously the President doesn't support this as he has closed Yucca Flats, at the cost of billions of taxpayer dollars to energy companies. If we would not have let the environmentalists push us around on nuclear power since Three Mile Island, we could have a progressive roadmap to phasing out older plants and pushing forward with many of the safer passive cooling reactor assemblies.[Edited on March 12, 2011 at 7:41 AM. Reason : ]
3/12/2011 7:40:10 AM
This is Chernobyl all over again, save for the reason it occurred.God help the people of Japan and the rest of the world as we figure out how to deal with this.I think the Japanese are smarter (and more concerned with their own people) than the Russians to handle this.
3/12/2011 8:44:04 AM
What videos are you talking about, I don't have the dummy tube on, just looking on the internets.This, posted minutes ago, says it wasn't a major melt down yethttp://www.cnn.com/2011/WORLD/asiapcf/03/12/japan.nuclear/
3/12/2011 8:59:46 AM
3/12/2011 9:30:22 AM
Yeah the biggest direct competitor for nuclear power is coal. It's not (yet) solar nor any other sustainable energy source. Ultimately though - terestrial power generation will likely be covered primarily by a combination of solar, wind, and tidal generation coupled with gen III+ and gen IV nuclear reactors for base load and gase turbine facilities for on demand peak power production. Of course if we don't progress towards an improved grid and a closed fuel cycle and can't phase out these older poorly placed plants then you can cut nuclear out of that list and replace it with "something else"
3/12/2011 9:56:47 AM
The Left WAS in the past extremely against the proliferation of nuclear power, as they saw it as an extension of the nuclear arms race. Greenpeace and the NRDC are very anti-nuclear power, and they probably donate a LOT more to the Democrats than to the Republicans. So yes, the environmentalists generally align with the left, and the anti-nuclear groups also align with environmental groups and the left.More recently there has been more splintering due to the fact that nuclear is the only option that can deliver huge amounts of power with no CO2 output, but the more liberal folks in the left are the one opposing the expansion and upgrading of nuclear plants in this country. The president has been flip-flopping on the issue, with expansions in the licensing process, while at the same time killing Yucca Mountain Waste Repository to appease Harry Reid. You may have seen the light on this, but I don't think Republicans need nearly as much convincing that nuclear is worth the small risks versus Democrats.
3/12/2011 10:08:30 AM
Keep in mind that the free market has declared Nuclear Power Plants a terrible investment because of the limitless liability potential. Now that we know this, the only way to build a Nuclear Power Plant is under government liability protection, which is not something I would defend.
3/12/2011 10:15:37 AM
^ My next question was somewhat related to that....is there any sort of a Nuke Plant moratorium here or is it more the government has made the economics so bad you just don't see anyone wanting to build?
3/12/2011 10:18:12 AM
^ It's more that building a nuclear plant is a decade+ long process. You have to hope that changes in party politics, regional politics, regional population density/location, as well as the increasing number of plants run well beyond their prime do not all conspire to sink the expensive and fragile project during that long time frime.In Japan there were a total of about 11 ABWR reactors scheduled to be in-construction by 2008. Two of them were built and completed and allowed for decomissioning of some of the oldest plants. 3 more were started but halted before they were brought online - due to anti-nuclear sentiments, political changes, and economic concerns. Two of those would have been online before now and allowed for the decomissioning of 2-3 of these older plants. The remaining ABWRs have either been cancelled or are "on order" indefinately. Would those 2 halted plants that were nearly complete have allowed for this particular reactor to be decomissioned or in the process of being decomissioned by now? Maybe, but probably not - there are a lot of plants that might have be decomissioned instead and it does not happen overnight.The thing is though you can't run these aging plants indefinately. You either have to replace them with newer nuclear plants that are safer and better able to weather the disasters you can expect or might be able to imagine - or- you have to replace them with something else. If you don't start to decomission 40+ year old plants built before the lessons learned over that time, particularly if they're sitting next to active fault lines, it's like playing russian roulette by yourself. You will eventually lose.The same is true for our own aging nuclear plants - particularly those on the west coast. We need to either begin to phase the oldest out and replace them with safer more modern plants (preferably located in safer areas) or we need to phase them out and replace them with something else. Transporting power efficiently from farther away would require an overhaul in our electrical grid but that's probably something we should do anyways too. Either way, they aren't built to last forever - either modernize them, replace them with newer reactor complexes in better locations, or replace them with something else. That or keep pulling the trigger.
3/12/2011 10:48:07 AM
But, there is nothing that prevented this plant from weathering the disaster. We have triple (and sometimes more) redundancy in aircraft that carry 20 people, why not for nuke plants? Why do they only have enough batteries to run the plant for 8 hrs? Why not enough to allow it to properly cool? I imagine we take care of this with new designs, but I doubt it's terribly expensive to retrofit old designs.
3/12/2011 12:00:40 PM
3/12/2011 12:11:52 PM
It's expensive to buy some extra batteries, enough to run pumps for 3 days, and put them on site in the event your back up generators don't work?
3/12/2011 12:21:49 PM
Well, the one thing that bothers me about the media coverage is the complete lack of knowledge they (and often their 'experts') have about radiation and exposure doses. 1000x background radiation isnt great, but you arent to get cancer from being exposed to that level. For example, background radiation at my house is about .014 millirem per hour (or .14 microsievert). If it is 1000 times that level, that amounts to 14 millirem (140 microsieverts). Most people get dosed about 350 millirem (3500 microsieverts) a year. I believe nuclear workers have a work dose max of around 3-5 REM a year (someone can correct me). So, if the background radiation is 1000x background, you'll get your yearly dose if you stay in that area for 1 day.Compare that to a full body CAT scan, and you will receive 1/3 the CAT scan dosage. So people get dosed with far more radiation in far less times with a CAT scan.This doesnt mean long term exposure isnt an issue, but the current levels arent an issue for the people in the immediate exposure area.Now, if the plant melts down, and it sends a lot of dust all over the place from the core, thats an entirely different issue.I wish we'd actually get measurements of exposure areas.[Edited on March 12, 2011 at 1:11 PM. Reason : .]
3/12/2011 1:01:53 PM
Isn't the Japanese reactor a light water one that can't melt down?
3/12/2011 1:16:18 PM
^I really enjoyed the fact that the professional opinion on nuclear reactors that was oft cited yesterday was somebody (can't find the source now) who was part of a movement to disassemble all nuclear weapons and nuclear reactors in the world. I'm sure he would never try to scare folks by giving only the worst case scenario, instead of giving a list of all possible scenarios and their likelihood of outcome. More sensationalism by the media.Appears the TEPCO has stated that the containment building blew, but the reactor and all its equipment is fine and they have just decided to pump seawater on it and likely kill the whole reactor in the process. Still better than a meltdown though, even if they have to deactivate the unit.Ah good, Greenpeace has chimed in:
3/12/2011 1:16:26 PM
3/12/2011 1:18:26 PM
can't have a day with no tides
3/12/2011 1:38:55 PM
CarZin, 3-5 Rem/Yr is correct.I have not been keeping up with what is going on over there with the power plant due to how mad i get listening to news reporters sound like complete idiots and then you have the no-nuke protestors....but apparently there emergency cooling system power supply failed? do they not have back-up to the back-up? dual redundancy so-to-speak? i do not know how most civilian power plants are designed...
3/12/2011 1:41:41 PM
3/12/2011 1:51:21 PM
^^Just like air travel. Its great until something goes bad, and then it REALLY goes bad. The few tragedies really overshadow the millions of people that fly and put in tons of miles with no problems whatsoever.
3/12/2011 1:51:44 PM
3/12/2011 1:56:10 PM
^pure nonsense (coming from jingoism? )They actually have 13 backup generators, which failed because of the tsunami. You assume that american design and operation requirements can handle that?And they have already flown in backup generators (no thanks to your expert advice or command of the facts available). [Edited on March 12, 2011 at 2:14 PM. Reason : Same way their buildings are much stronger than ours. just complete fucking nonsense from you]
3/12/2011 2:11:40 PM
so I'm about 160 miles from Fukushimahmmm I'll probably be safe
3/12/2011 2:17:25 PM
for the same country that doesnt allow US nuclear subs in it's harbors, I doubt they would be so lacks on nuclear power plants on their island. This seems like it might be one of those cases where everything fails and you can't engineer away 100% of the risk.
3/12/2011 2:58:13 PM
On the International Nuclear and Radiological Event Scale(INES) this accident rates a level 4 on a 7 point scale where Chernobyl rates 7 and 3 mile island rates 5. I mean this sucks for sure but I wouldn't worry too much about it. It is important to note that there a two containment structures which house the reactor vessel. The explosion occurred between the primary(innermost) containment structure and the secondary. So if push comes to shove there are still fission product barriers intact. In the end they are probably going to flood the vessel and primary containment, call it a day, then write unit 1 off as a really, really, really, really, really, really expensive and useless space heater.As to the question about why the nuclear industry doesnt have multiple layers of safety systems...they obviously do otherwise this accident would have gone down similar to Chernobyl. So far the only injuries that resulted from this are two employees with a couple of broken bones. As of a few hours after the explosion, the dose levels at the site boundary are on the order of 7 millirem per hour, which, while non-zero, its nothing to cry home about. This will likely drop dramatically when they stop venting.
3/12/2011 3:07:10 PM
On a fun side note, as Charybdisjim points out, a hydrogen explosion can be easily explained via the exothermic metal-water reaction that takes place when zircalloy reaches the magic temperature of 2200 F (i.e. "meltdown"). Partial meltdown has probably already happened.
3/12/2011 3:43:04 PM
3/12/2011 3:51:50 PM
3/12/2011 4:22:50 PM
Nah, just that failing companies be allowed to fail. If a worse scenario would have happened where it Chernobyl'd, at least we'd be happy knowing we have that little bit of extra liberty despite the complete wasting for...forever...of a square miles of Japanese country side and maybe a few deaths and cancer cases.
3/12/2011 4:22:58 PM
^^^ in this case, yes. it seems quite sensible to require operators of a potentially dangerous machine like this to follow rules in order to do so. I know I wouldn't want some random guy on the street to be putting together his own nuclear reactor in his backyard with a couple steel pipes and a 55-gallon drum.
3/12/2011 5:11:07 PM
3/12/2011 5:52:37 PM
3/12/2011 7:08:08 PM
3/12/2011 9:17:31 PM
3/13/2011 1:16:43 AM
Can anyone point out specific (or even vaguely specific, lulz) regulations that are driving the costs up? It's sort of taken as a given but is that really the case?
3/13/2011 9:02:11 AM
This might sound terrible but I look at this proof that nuclear is safer than people think (assuming that this doesn't get much worse). This is a worst case scenario event and yet the operators so far have manage to minimize the public dose to a completely reasonable level. I've heard reports that the PEAK radiation levels have reached 1557 micro-sieverts/hr or 155.7 mrem/hr. That is nothing and can in no way endanger the public health. I would have no problem standing in a room with a 155.7 mrem field. You also have to take into account that this dose rate is significantly less the further you move away from the plant. The events that have taken place at Fukushima are seemingly unimaginable, however, these are the type of events that operators train for. This plant was near the center of an 8.9 earthquake, they lost offsite power, a tsunami took out emergency backup power and a H2 explosion destroyed the building outside their drywell. This also includes multiple smaller system and equipment failures that have occurred during this time. I don't think people begin to realize what these operators and this plant is going through right now.
3/13/2011 10:19:47 AM
3/13/2011 10:59:58 AM
3/13/2011 11:21:31 AM
3/13/2011 1:16:30 PM
So the radiation they are detecting is because the venting facility exploded because there was no power for the fans?
3/13/2011 1:29:35 PM
nuclear power in this country needs monumental changes in order for the G&T companies to take it seriously. Until we're allowed to cycle load and recycle spent fuel, there is no reason to dump money into nuclear when natural gas keeps getting cheaper and more plentiful. Only being able to use nukes for base load makes them much less attractive than natural gas and coal as a fuel source.Utilities like Dominion and Duke made up for the inability to cycle load on their nukes by building massive pumped storage hydro facilities. Unfortunately, the areas where these units can be built is limited, and they have their own environmental concerns that make present day permitting almost impossible. We're making some good advances with compressed air storage systems, but they are nowhere near the energy storage capacity of pumped storage. I believe they suffer from higher efficiency losses too, because pumped hydro facilities make up for some of their efficiency and evaporation losses through rainfall adding to the top reservoir.The issues that occurred in Japan this week definitely didn't help matters, but I don't think anyone in this country was really taking nuclear power seriously beforehand.
3/13/2011 2:56:06 PM
interesting conversation. way over my head, but interesting.
3/13/2011 2:58:45 PM
That's what happens at an engineering school i guess...I wonder if we were a liberal arts school, would our normal policy discussions go like this...?
3/13/2011 4:10:17 PM
3/13/2011 5:57:50 PM
^truth
3/13/2011 6:10:54 PM
this event in japan has scientifically proved that nuclear plants are naturally unsafe and should never be built. i support a plan to phase them out over a 6 year period and think that they should all be closed sooner than that.
3/13/2011 10:14:39 PM
I agree. I will go ahead and cut all power usage in my house to make up for the loss of power generation......Any structure is naturally unsafe on top of a 8.9 quake and a tsunami.In Japan it would be almost impossible to phase anything out in 6 years. They have to many of them, and you cant replace the power output with anything anywhere near that time frame.Nuclear is necessary, just doesn't need to be built at the intersection of 3 tectonic plates.
3/13/2011 11:18:53 PM
Those plants are also the first generation of plants. The oldest, and didnt have the lessons learned from years of design revisions to improve on it.
3/13/2011 11:22:25 PM
Yeah I'm more in favor of phasing out the old plants while replacing them with higher capacity passively-safe new plants. Many of the Gen III+ designs (some of which have been built in europe and japan) would not have seen this sort of dramatic failure in the same situation. There are designs which require no external power nor even moving parts to circulate coolant - they use gravity and the reactor's own heat to do the job.I do not think we should get rid of nuclear power. I think we should have a long term commitment to modernizing our nuclear power plants - which are a crucial part of our base load power production. We also need to commit to modernizing our power grid so that the newer safer plants we should be replacing the old ones with can be built in more ideal locations than on top of a major fault line. Many of the current and near-future designs also produce far more power than the aging designs currently in use. This means that if you built them while decommissioning the old plants and include burner reactors or accelerator driven waste transmutation systems into the mix you would:1) Increase the total ammount of power produced by nuclear energy2) Not increase the number of nuclear plants in operation3) Decrease the number of nuclear plants in operation near fault zones and other areas of concern4) Reduce the volume of waste produced as well as reduce the level of hazard presented by the waste you do produce (transmutation for the win)Failing that though - it might be nice to set up a system for facilitating the upgrade and improvement of existing plants. Some sensible upgrades are rendered so costly by the procedures involved with what might otherwise be an inexpensive way to add safety that they are just not worth doing. If that could be made easier while also not compromising safety- well that would be a good thing.It has to be frustrating for nuclear energy safety experts that one of the principle effects of anti-nuclear power pressure has been to increase the length of time that aging plants remain in operation. Popular pressure and economic pressure makes it too difficult for some utilities to construct newer, more efficient, higher capacity plants so they can not do without the base-load capacity provided by even some of their oldest existing plants. Allowing companies or helping companies to build new plants will also allow for the decommissioning of old ones. Fighting the construction of new plants forces them to keep the old plants open longer and longer and actually increases the long term risk of nuclear accidents.[Edited on March 14, 2011 at 12:25 AM. Reason : ]
3/14/2011 12:20:56 AM