Suppresed Video of Japanese Reactor Sodium Leak 341
James Hardine writes "Following an announcement this week that the infamous Japanese Monju fast-breeder nuclear reactor would be re-opened with a new plutonium core, Wikileaks has released suppressed video footage of the disaster that led to its closure in 1995. The video shows men in silver 'space suits' exploring the reactor in which sodium compounds hang from the air ducts like icicles. Unlike conventional reactors, fast-breeder reactors, which 'breed' plutonium, use sodium rather than water as a coolant. This type of coolant creates a potentially hazardous situation as sodium is highly corrosive and reacts violently with both water and air. Government officials at first played down the extent of damage at the reactor and denied the existence of a videotape showing the sodium spill. The deputy general manager, Shigeo Nishimura, 49, jumped to his death the day after a news conference at which he and other officials revealed the extent of the cover-up. His family is currently suing the government at Japan's High Court."
Governments can suppress the videos (Score:5, Funny)
radioactive sodium too (Score:5, Informative)
Re:radioactive sodium too (Score:5, Informative)
Re: (Score:2, Interesting)
What does Na-24 decay into, and how dangerous is that? How long does that stick around?
Re:radioactive sodium too (Score:5, Informative)
Na-24 beta decays into Mg-24, which is stable and not dangerous.
Re: (Score:2)
The big issue here seems to be not the coolant itself - it seems to be a relatively good coolant to use - but the fact that the accident happened. The larger problem that could have occurred would have been a core meltdown instead, and that would have been serious.
This stresses the fact that nuclear power has it's dangers, and that it's necessary to watc
Re: (Score:2)
Re:radioactive sodium too (Score:5, Insightful)
The big issue here is not that an accident happened -- accidents have a way of doing that from time to time. Things go wrong, the best plans have flaws, people make mistakes. This is true of
The big issue here is that the government lied to its people and the fact that they lied was covered up. We need more stories like this of governments around the world because it might just put a dent in the (very dangerous) "government is your friend" mentality that is especially prevalant in the USA.
Personally I wish the definition of treason were expanded to include "issuing false statements to the people with the intent to deceive when done by any government official" or something to that effect. Meaning, you can make an honest mistake and it's no big deal; deliberately lie to the people and you get removed from office and prosecuted to the fullest extent of the law. Does that sound harsh? Perhaps, but they don't seem to think so when they "make an example" of us, as we have seen with the War on (Some) Drugs and are now seeing with copyright law. Not to mention, almost any concept I have of "harsh" goes out the window when talking of wrongdoing on the part of people who consider themselves our masters.
This isn't Athens where people were chosen for public office by lottery. These are people who seek power and have worked very hard to get it. What's wrong with giving them a reason to be cautions with how they use it?
Re: (Score:3, Interesting)
It's possibly more "government is your friend and anyone who thinks otherwise is a nutjob conspiracy theorist(tm)".
Personally I wish the definition of treason were expanded to include "issuing false statem
Re:radioactive sodium too (Score:5, Informative)
Siiiigh, again.. The leak was in teh SECONDARY LOOP. It wasn't any radioactivity in it. Nada, zero, zip... Yes, it was a bad accident, but the only thing nuclear about it was that it occurred in a nuclear power plant. The same thing would be much less likely to occur in the radioactive primary loop, because that counts as part of the nuclear island and is hence under much stricter safety requirements.
Re:radioactive sodium too (Score:5, Insightful)
What, exactly, do you think the energy of a 2,000 pound bomb going off in the middle of a reactor will do in terms of letting more sodium leak? What do you think letting more sodium leak will do in terms of further explosions? What do you think all of this will do to the primary?
This was a Very Bad Thing (TM), but could have been far worse.
Re: (Score:2)
So what you think of regular Mg metal is mostly Mg-24.
Re:radioactive sodium too (Score:5, Insightful)
Re: (Score:3, Informative)
The thing to keep in mind is that sodium is so popular as a reactor coolant precisely because it doesn't form a lot of long lived radioactive isotopes when irradiated in a nuclear reactor.
Wrong. Sodium does form radioactive isotopes like Na-24 (that has a half-live of 15 hours). Water cooled reactors and CO2 cooled reactors produce shorter half-live isotopes like N-17 (that has a half-life of a couple seconds). Water in a PWR or BWR will become slightly radioactive over time due to stripping slight amounts of cobalt from valve seats (in a form like stellite which is used to make hard valve seats) and from the release of fission products that are not due to the fuel particles but from ura
Re: (Score:3, Informative)
1.) The 15 hour half-life of Na-24 prevented immediate entry to the reactor in case of repair. Five half lives (the standard assumed for total decay away) means you're cooling your heels for about three days before you can really do any work. It makes quick response - like the kind Monju would have liked to
Re:radioactive sodium too (Score:5, Funny)
Re:radioactive sodium too (Score:5, Informative)
The Japanese won't put soy sauce on rice.
Mod parent up! (Score:5, Interesting)
So mod parent funny or informative!
Re: (Score:3, Informative)
Re:Mod parent up! (Score:4, Interesting)
Seriously though, compared to America, Japan really doesn't have a "we do it your way" mentality with food. I once had to endure a twenty minute back and forth between a friend, a translator, a waitress, and (presumably) a cook because my friend tried to order his pizza without squid. Frankly, ordering *anything* without squid in Japan is probably a stretch, but what was worse, was that even after our translator was like "a special order is very difficult to do in Japan," which is polite translator speak for THIS WILL NEVER HAPPEN, STUPID AMERICAN, he then spectacularly failed to take the face-saving bait offered by the waitress, "Are you allergic to squid?" and said "no I just don't eat it, I'm vegetarian." Here's a hint: If a Japanese person makes a suggestion like that to you in a service situation, take it!! I don't even know how this scene ended (but I do know the chef's next comment, conveyed by the waitress, was "but vegetarians eat squid"), but I do know it took a long time to finally receive my tasty beef curry, Japan's proudest culinary achievment.
Japan doesn't have a culture -- Japanese people do (Score:5, Informative)
There is also a wide spectrum of cooks having egos. (There is a bad habit among a certain type of Westerner to assume that any odd action taken by a Japanese person is because they are Japanese. That is one theory -- another is that the cook just can't be bothered to help you, or is excessively proud, or is just a disagreeable person. All of thsee will be right at least part of the time.) I assure you, if you visit enough hoity-toity restaraunts in NYC, you will fairly quickly find someone who would not be willing to accomodate a simple request that wasn't in their "vision" for the food. ("Where is the ketchup?" "THIS IS A FOI GRAS AND CAVIAR PATTE SERVED IN A LIGHT BALSAMIC VINAGRETTE."* "I like my foi gras with ketchup!"
(Sidenote: I do E->J and J->E translation in Japan as one of my work duties. I am not, however, a professional translator. The difference is that the folks who pay my salary pay me to *resolve* issues like "I just don't want squid" rather than just passively relaying the "Oh, we can't do that" response. I understand that the standard practice among professional translators is that you are supposed to not get in the way of the speaking parties at all -- this is why I am not a professional translator, I just translate for money.
P.S. For those of you considering a job in this general line of work, the pay is a heck of a lot better if you pitch yourself my way. Most clients do not appreciate the value of a beautifully articulated "The waitress says no" nearly as much as they do "OK, so here's what is going on here, and here is what I did to get you your squidless pizza. Aren't you glad you hired me." The same fundamental issue scales straight from "I can't give you pizza w/o squid" to "I can't approve that $1 million deal you are suggesting".)
* Sorry, I only eat at restaraunts that cost more than $15 when the client is paying, and then I'm having what he is having, so I have absolutely no clue whether this is actually a plausible French food combo or not. Bonus points: consultants get to eat at dinner, translators don't.
Re:Mod parent up! (Score:4, Funny)
Re:radioactive sodium too (Score:4, Informative)
Except that the leak was in the secondary loop, which is never in contact with the core, and hence not radioactive. Had the leak been inside the primary loop you wouldn't have been able to walk up to it with a video camera because there would have been quite a bit of radiation shield and concrete in the way.
Not in this case, apparently (Score:2)
According to Wikipedia [wikipedia.org],
"Secondary" means that this sodium didn't pass through the reactor core so it didn't become radioactive.
Also (Score:5, Funny)
Japanese government doesn't even try to cover it up.
Re:Also (Score:5, Insightful)
Re:Also (Score:5, Informative)
Note to web "masters" everywhere: you cannot distribute huge files to millions of people using MySQL and SSL. Full stop. Upload that shit to Amazon S3 or Akamai or YouTube or _anything_ other than mediawiki. Thanks!
Re: (Score:2, Interesting)
Re: (Score:3, Informative)
If you use a lot of SSL/TLS (the S in HTTPS) you might need an SSL off-loader, a PCI based hardware accelerator or a CPU containing hardware crypto. The first one is most safe
Youtube link (Score:5, Informative)
Re:Youtube link (Score:5, Informative)
Re: (Score:2)
Re: (Score:3, Informative)
NPJ Video News No. 3
Video taken just after the sodium leak accident at Monju, hidden by the PNC - the so-called 2 o'clock video
Just after the accident, the PNC sent employees to the site to film the leak.
However, due to the graphic nature of the footage, the PNC hid it
The PNC explained that they hid it because "it has no value"
With your own eyes, we want you to judge why the PNC hid the video
This video was not only hidden at Monju (Fukui Prefecture),
it was also discovered later that
Re: (Score:3, Informative)
"Sodium mist fills the air" and "The mist gets deeper" -- the camera was out of focus and it was quite dark in there; no "sodium" mist; a second after they filmed the "sodium mist", the "mist" dissapeared. There was not enough light, and the operator had to use a large aperture, so the range at which the objects were in focus was short: move the camera from the back of the shining suit in front to the wall that's 3m away and you get "mist".
"Footsteps on white sodium" -- not sodi
Re:Youtube link (Score:5, Funny)
Narrator: In A.D. 2101, war was beginning.
Captain: What happen ?
Mechanic: Somebody set up us the bomb.
Operator: We get signal.
Captain: What!
Operator: Main screen turn on.
Captain: It's you!!
CATS: How are you gentlemen!!
CATS: All your base are belong to us.
CATS: You are on the way to destruction.
Captain: What you say!!
CATS: You have no chance to survive make your time.
CATS: Ha Ha Ha Ha
Operator: Captain!! *
Captain: Take off every 'ZIG'!!
Captain: You know what you doing.
Captain: Move 'ZIG'.
Captain: For great justice.
Re: (Score:2, Insightful)
Re: (Score:3, Informative)
I give you one chance to guess why the reactor was built to carry the hot sodium far away from the reactor before using the heat from it to boil water for the turbines. Also, the white powder was probably not sodium ( sodium is silver-like in colour ) but rather sodium-oxides produces when the sodium is oxidized in the air.
Now for the record, had those pipes actually been ca
This video will drive one procedural change (Score:5, Insightful)
Safe Nukes (Score:3, Informative)
Re: (Score:2, Informative)
The fast breeder or fast breeder reactor (FBR) is a fast neutron reactor designed to breed fuel by producing more fissile material than it consumes. The FBR is one possible type of breeder reactor. [wikipedia.org]
WRONG (Score:2)
Re: (Score:2)
It makes me sad how much baseless fear there is of nuclear power out there. A coolant leak is a pretty major breakdown as Nuclear disasters go, and AFAIK nothing truly bad happened in th
I am amazed that we are not doing nuclear ships (Score:2)
Nothing will stop the resurgance of nuclear power (Score:4, Insightful)
This SHOULD show that even a "disaster" is minimal by nuclear standards and that safety is about a billion times better than any type of plant, but who knows how this will be interpreted by those who are inclined to panic at what they don't understand.
Re:Nothing will stop the resurgance of nuclear pow (Score:4, Informative)
Re: (Score:2)
Too bad.
Re: (Score:3)
Re: (Score:3, Insightful)
Democratically elected governments do not remain so for very long if they are allowed to muzzle citizens and the media.
Re:Safety is not the issue (Score:4, Insightful)
what? (Score:5, Interesting)
Re:what? (Score:5, Insightful)
Face it, nuclear power is Bad, so the fact that there is a video showing a bunch of kids in hazmat suits re-enacting Blair Witch in their school basement should we all the proof you need. Any grainy image of sewage pipes is a bonus.
Re: (Score:2, Funny)
Re:what? (Score:5, Interesting)
Re:what? (Score:4, Interesting)
In fact when heated in air in quantities more than a few grams, sodium will simply burn (with violent flames) generating that white-yellow "smoke" which is a combination of sodium oxyde (Na2O) and sodium peroxyde (Na2O2).
Note that both sodium oxyde and sodium peroxyde are highly reactive, burning in contact with water, generating sodium hydroxide. Sodium peroxide also reacts violently with flammable organic materials that can easily "give" a hydrogen or hydroxil radical, such as alcohols. In this reaction, it generates more sodium hydroxide. Sodium vaports will slowly react with the oxygen in the air, again generating white sodium oxyde.
All these compounds will cause severe burns even if you expose the human skin to less than of gram of this stuff. Concentrated sodium hydroxyde simply melts the skin, nails and bones, and sodium oxyde/peroxyde is even more dangerous. In fact - this is how soap was made for centuries - just boil some fat in concentrated sodium hydroxyde and soon you will have some soap.
It's obvious why these workers have to wear special suits.
More fun stuff about sodium - check out the famous Sodium Party that Theodore Gray had a while back (or wikipedia)
Next (Score:2)
Maybe they were just trying to fight the monsters (Score:2)
Sodium reactors and the Navy (Score:5, Interesting)
Re:Sodium reactors and the Navy (Score:4, Informative)
Oh, and btw, the summary is misleading. Sodium is very corrosive to concrete and a lot of other materials, but provided it remains pure ( i.e, doesn't mix with water / air ) it is in fact very non-corrosive to steel, which is one of the reasons why it is used. It is certainly a lot less corrosive than 300 C water with boric acid in it.
Re: (Score:2)
The Soviets experimented with metal-cooled reactors in their Alpha class submarines. I believe the reactors in those boats employed bismuth, though. The problem with metals is that it was a maintenance nightmare. The ruskies had to build piers with steam plants on them just for the Alphas so the they could dock and shut down their reactors, less the liquid bismuth solidify in the coolant pipes and essentially writing off the entire boat. I do believe
Re: (Score:3, Informative)
Re:Sodium reactors and the Navy (Score:4, Interesting)
An urban legend without a shred of truth to it. Rickover in fact was initially in favor of sodium cooled reactors - because, in theory, they would allow plants that were more compact and higher power than water cooled reactors. However, as usually happens, theory and reality failed to jibe. Sodium plants turned out to be heavier, more expensive, more complex, and far more maintenance intensive that water cooled plants.
Ever the pragmatic engineer, Rickover chose to stay with what worked and cancelled the sodium reactor program.
I find it odd (Score:2)
Re: (Score:3, Informative)
Those arn't space suits! (Score:4, Funny)
Worse than what? (Score:3, Insightful)
Also, let's talk about the environmental effects. My family actually has a history with this, living in West Virginia and finding work in the mines. Ever heard of a process called "strip mining"? Tearing the tops off of mountains and letting mining sediment flow into valleys and adjacent creeks? Nuclear waste is more dangerous pound per pound, but it also can be contained, stored, and most importantly, reprocessed into other nuclear fuels. Coal burns and releases carbon.
Maybe I'm crazy, but I'm willing to risk the occasional "breeder screwup" every couple of decades for cheaper, more environmentally-friendly fuel that doesn't involve razing land en masse and sending people into under-inspected mines because the product itself is simply so worthless unless produced in bulk.
Uranium isn't a solution to any major environmental problem, considering that such a novel idea simply doesn't exist right now. But it's still more than coal. It's something I'd be willing to put myself behind if a nuclear plant were proposed near my home.
Suicide (Score:3, Funny)
I don't get these "suicide to save face" issues.
I like Benders approach better.
Bender: I am so embarrassed.. I wish everyone else was dead!
Re:Video down? (Score:5, Informative)
Re: (Score:2)
Re: (Score:2)
"nuclear reactor would be re-opened with a new plutonium core,"
"Someone set up us the bomb!"
Re:Nuclear Power and Global Warming (Score:5, Insightful)
Re:Nuclear Power and Global Warming (Score:5, Insightful)
And as we all know, that's not news because it isn't sensational enough.
One study I found when searching indicates that 25 reactor meltdowns per year would be required to being it inline with coal pollution deaths.
Re:Nuclear Power and Global Warming (Score:5, Informative)
http://www.physics.isu.edu/radinf/np-risk.htm [isu.edu]
Re: (Score:2)
Scrubbing the gaseous elemental Mercury from the combustion gases is very expensive and not that efficient and many countries don't even bother. Look it up in your own country.
I'd rather have the *fear* of an unlikely contamination of my environment from non-global-warming nuclear power than the *certainty* of air pollution and Mercury in my f
Re:Nuclear Power and Global Warming (Score:5, Informative)
http://www.sciam.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste [sciam.com]
Re: (Score:3, Insightful)
I was just in my home state of Pennsylvania yesterday and saw a bumper sticker asking "Why not coal?" (Coal Miner's Union) The major industry around my area used to be anthracite mining, and when that collapsed, the town kinda went to shit, although it's coming back slowly. Given that, I understand why they'd want coal, just like I'm sure people in Detroit want the auto industry back, and the midwest wants ethanol.
Unfortunately, even though it would probably be a boon to my home town, I can't agree
Re: (Score:3, Insightful)
Given that, I understand why they'd want coal, just like I'm sure people in Detroit want the auto industry back, and the midwest wants ethanol.
Perhaps if there wasn't that blow delivered to them in the 70's-80's (from environmentalists and people with a hate for Detroit/"Big Labor" that exceeds the hate for Bush), that mistake wouldn't have been realized.
You underestimate the amount of people who will buy Detroit/UAW(and not at exhorbitant prices) despite the push to kill it. They are not of the type that will just settle for an import just because some non-voting person wants us to go in a direction contrary to the citizens' wishes.
I was just in my home state of Pennsylvania yesterday and saw a bumper sticker asking "Why not coal?" (Coal Miner's Union) The major industry around my area used to be anthracite mining, and when that collapsed, the town kinda went to shit, although it's coming back slowly.
Maybe there
Re: (Score:2)
=Smidge=
Re: (Score:2)
Technically "meltdown" is when the plant shuts down and the carbon rods retract.
A meltdown is when for some reason the nuclear reaction isn't mediated, and the reaction "runs away" or takes off out of control. This would happen in older reactors if there is a loss of coolant and the control rods weren't dropped into the reactor (also known as a SCRAM) to stop the nuclear reaction from occurring. With breeder reactors, I'm unaware of what their procedure is for handling any sort of failure with the sodium coolant.
Re: (Score:2)
Re: (Score:3, Interesting)
The retraction of the carbon rods is called meltdown.
No, a meltdown is when the fuel rods and surrounding material starts to melt. Worst case, the fuel completely melts and pools at the bottom of the reactor container, melts through the floor of the reactor container, and keeps going for a while till enough other material, particularly neutron-absorbing material (graphite, bismuth) (which in the worst case for old, poorly designed reactors may be ample portions of bedrock underneath the reactor) has mixed in to bring the fuel density below criticality. Ther
Re:Nuclear Power and Global Warming (Score:5, Informative)
Coal mining accidents might not incur the risk of significant radioactive contamination, but the combustion of coal does release massive amounts of radioactive material into the atmosphere [ornl.gov], and people living near coal-fired power plants are exposed to more radiation than those living near nuclear power plants.
I've always found these statistics to be interesting:
Of course, in the case of an extreme nuclear accident, as in Chernobyl, we have a very big problem to deal with right away that wouldn't be possible with coal. But I think it's worth remembering that a great deal of radioactive material is accumulating from coal-fired power plants, and that could someday be a major problem too. Nuclear power is not the only source of radiation released because of human activity.
Re:Nuclear Power and Global Warming (Score:5, Informative)
Of course, in the case of an extreme nuclear accident, as in Chernobyl, we have a very big problem to deal with right away that wouldn't be possible with coal. But I think it's worth remembering that a great deal of radioactive material is accumulating from coal-fired power plants, and that could someday be a major problem too. Nuclear power is not the only source of radiation released because of human activity.
Re:Nuclear Power and Global Warming (Score:5, Informative)
Oh if that was the ONLY thing that was wrong with it...
1)The end of the control rods were made of graphite, which accelerated the reaction rather than slowing it when the operators pushed the panic button.
2)The channels that contained the control rods were far too narrow, causing the control rods to get jammed when they deformed due to the intense heat.
3)The reactor did not have a containment building, allowing the radioactive gases to escape into the atmosphere after the accident blew the roof of the reactor itself.
4)The reactor core was unusually large, containing much more nuclear fuel than other reactor designs, thus making the radioactive release worse.
5)The reactor was staffed with uneducated workers that didn't have significant experience with nuclear reactors.
6)The operators were not told about the design problems with the reactors even thou they were well known at the time.
7)The operators ran the reactor outside of safety regulations, withdrawing many more control rods than the reactor was designed to operate with ( that this was even possible is another design flaw ).
Re:Nuclear Power and Global Warming (Score:5, Insightful)
zing!
Re:Nuclear Power and Global Warming (Score:5, Interesting)
Since the accident, the natural wild life has returned in full force, and the region's ecosystem is healthier than it has been for centuries. Obviously without an in depth study we cannot be certain of mutation and cancer rates in those animals. But I'll venture a guess that natural selection took its course, and the overall population is healthy, allowing it to adapt and thrive in a mildly radioactive environment.
http://news.nationalgeographic.com/news/bigphotos/33784558.html [nationalgeographic.com]
So there goes your whole argument. Now read up on blue fin tuna that has such large quantities of mercury that even 6 pieces of sushi per week exceeds the safe limit. Read about the Exxon Valdez spill and countless others that directly destroyed entire ecosystems.
At this point nuclear energy is safer than any conventional other energy source. It is also the only economically viable energy source, at least for the time being. People who believe that solar, wind, and other renewable energy sources are the way to go obviously have NO idea how much electricity is consumed in industrial processes. Statements like "this windmill can power thousands of homes" are meaningless, when a single steel foundry consumes that much in a half hour.
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
http://www.sciam.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste [sciam.com]
Re:Nuclear Power and Global Warming (Score:5, Insightful)
Read up on 'loss of blade' accidents for windmills, dam failures for hydro, and how coal releases radiation (lots of it) and other toxins (lots of them). Read up on what chemical compounds are used in solar cells, or just how hot a commercial sterling solar engine is at the mirror's focal point. Look at the political consequences of breeders, but also at the political consequences of the existing fuel oil demand. Look at the environmental consequences of nuclear, but also at the environmental consequences of big oil. Find out how even wave and tide, if scaled up to produce tens or hundreds of gigawatts, means thousands of small boat accidents a year, plus Manatees and probably many other species will inevitably become extinct and whole ecologies such as the everglades will likely follow. For any power source, read up on where it is to be located, and the human costs of sending the power to where it is to be used. THERE IS NO SAFE!
Quite right, and since the dawn of the human race (Score:5, Insightful)
We are also poor at judging risks outside our biological programming, which is why we deem it a reasonable trade off to have over a hundred thousand people a year across Europe and the US die in accidents, rather than have universal public transport. If a hundred thousand deaths a year is OK so we can go to the office exactly when we feel like it, why isn't it OK so we can turn on the dishwasher exactly when we feel like it? - and that's meant to be a serious question.
Re:Quite right, and since the dawn of the human ra (Score:4, Interesting)
It's more of the poor risk analysis. Deaths from coal based pollution and auto accidents happen daily in a series of small dramas affecting a handful of people at a time. When a nuclear accident happens it's all over the news and millions are involved in the same drama at the same time. That skews our risk assessment so that the emotional reaction to the infrequent large event is much greater even though the many small and frequent events kill far more people.
reletive novelty also plays a role. A video of one guy being killed by a bull will get a LOT more airtime than a thousand fatal carcrash videos will.
Jaws scared a great many people out of the ocean. I would guess that many times more people have died on the way to or from the movie than due to shark attack.
Re: (Score:2)
Be honest though. As long as it is safe for humans, we don't care if it kills off every lif
Re: (Score:2)
Re: (Score:2)
Re: (Score:3, Informative)
Actually, breeders can do both. Early examples were primarily for weapons grade Pu production but many designs exist geared more for commercial power production. The Pu they produce is well suited for further use in a reactor, but is much more difficult to process into weapons material. That, of course, is a big plus these days when the world has quite enough bombs.
Re:Nuclear Power and Global Warming (Score:5, Informative)
A minor correction... (Score:3, Informative)
Re: (Score:3, Insightful)
There are other coolants you can use for breeder reactors. My personal favorite is the lead cooled system. It can safely shut itself down even without any computer or operator intervention (thanks to thermal expansion of the core ), there is no pressure in the reactor, so it can't explode, lead doesn't boil at the temperatures involved, so a loss of coolant accident as happened at TMI is unlikely, and it ca
Re:why sodium? (Score:5, Informative)
a) It is liquid at temperatures suitable for the reactor operation meaning you don't need any pressure in the cooling system. In contrast pressurized water reactors and gas cooled reactors need to keep the entire core under high pressure.
b) Sodium is a metal and hence conducts heat very well, this allows you to build a very compact reactor that is still capable of dissipating its heat after shutdown even if the cooling pumps were to fail.
c) Sodium doesn't absorb neutrons nearly as much as water does, and this allows you to build a reactor which produces more plutonium than it consumes, thus eliminating the need to enrich uranium.
d) Sodium atoms are heavier than hydrogen atoms, so the neutrons will not lose their energy as quickly. As a consequence the neutron spectrum is a lot harder, and capable of destroying much of the long-lived waste. The Waste from a breeder reactor would hit uranium levels of radioactivity in 300 years rather than tens of thousands of years.
e)While sodium is corrosive when mixed with air or water, pure sodium is almost completely non-corrosive to steel. This is in sharp contrast to 300 C pressurized water with boric-acid dissolved in it. A sodium cooled reactor generally experiences virtually no corrosion to the reactor core unless an accident occurs.
Basically, if it wasn't for the fire-hazard sodium would be close to an ideal reactor coolant.
Re: (Score:3, Informative)
The problem is when Na comes in contact with water, it gives off hydrogen gas, and being that the rxn is exothermic, the hydrogen can be ignited resulting in an explosion.
2Na + 2H20 --> H2 + 2NaOH
Re: (Score:3, Informative)