There is almost guaranteed significant radiation release.
quote from slashdot:
The outer walls of the Reactor 1 building have partially
blown off, leaving only what looks like a steel frame.
NHK is saying that a sensor within 5km of the plant is detecting
radiation levels approaching 1015 microsieverts
- that is apparently a year's worth of radiation exposure
EACH HOUR
People in the danger zones are being told to cover faces
with wet towels, avoid eating vegetables and other fresh foods,
and refrain from drinking tap water.
"This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion at the Fukushima-Daiichi nuclear plant. "The nuclear agency says that they have detected caesium and iodine outside the unit, which certainly indicates fuel melting at the very least," he says. "Once you have melting fuel coming into contact with water, that would almost certainly be the cause of the explosion." (BBC)
(EDIT)
More from Walt Patterson of Chatham House. He says the presence of the radioactive caesium in the surrounding area does not pose a huge threat to public health in the immediate aftermath of the explosion. "What would be serious is if there was an explosion or fire that lifted this stuff high in the air, meaning it could get carried over a wide area."
The reactor building (the shield wall/missile shield) is also made of steel-reinforced, pre-stressed concrete 0.3 m to 1 m (1–3 feet) thick.
The concrete surrounding the building is now gone (due to excess pressure).
Second edit:
[6:54 a.m. ET, 8:54 p.m. Tokyo] The explosion at Japan's Fukushima nuclear plant was not caused by the nuclear reactor but by "water vapor that was part of the cooling process," Chief Cabinet Secretary Yukio Edano said Saturday. He said no harmful gases had been emitted by the explosion.
[6:44 a.m. ET, 8:44 p.m. Tokyo] Japanese Prime Minister Naoto Kan confirms that the evacuation area around the Fukushima Daiichi nuclear plant has been increased to 20 kilometers. But no one has been harmed by radiation, he says.
Third edit (from the BBC):
1218: It seems clear now from Mr Edano's comments that the nuclear plant building that was blown apart earlier did house a reactor, but the reactor was protected by its metal casing.
1216: Government spokesman Yukio Edano says the pressure as well as the radiation at the Fukushima-Daiichi nuclear plant has fallen following this afternoon's explosion.
So the "explosion" has actually helped the situation.
"We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside," [Japan Chief Cabinet Minister Yukio Edano] said.
"At this point, there has been no major change to the level of radiation leakage outside (from before and after the explosion), so we'd like everyone to respond calmly," Edano said."
While damage to internal containment structures are possible, the building is likely to be resistant to these kinds of explosions.
A (what I guess) is a similar explosion happened in the reactor building in TMI, and the risk of an explosion such as this seems to be well known. The reactor building was probably prepared to absorb the explosion away from the containment structures, making it look much worse than it is.
Got a mail from WANO relayed to me, below is the interesting part about the explosion.
-----
1. Hydrogen explosion occurred at 15:36 between containment and reactor building of Fukushima Daiichi unit 1. Walls of reactor building were blown out or damaged.
2. It was confirmed that unit 1 containment integrity was maintained.
Explosion was not inside the containment as it is inert.
3. Radiation level at the Fukushima Daiichi site border once increased when containment vent was conducted and reached 1,015 micro Sv per hour around the time when explosion occurred; however, the radiation level turned to decrease after the explosion down to 860 at 15:40 and 70.5 micro Sv per hour at 18:58.
4. Government has agreed to TEPCO decision to fill the entire containment up with sea water. The filling sea water will contain boron. TEPCO started the work for filling up at 20:20.
Kyodo News agency said radioactive caesium had been detected near the site, quoting the Japanese nuclear safety commission. Radioactivity rose 20-fold outside, reports said. (EDIT: this was before the explosion)
The plant "may be experiencing nuclear meltdown", Kyodo and Jiji reported before the explosion, while public broadcaster NHK quoted the safety agency as saying metal tubes that contain uranium fuel may have melted.(AFP)
Is 20-fold increase in radioactivity actually hazardous? I was under the impression dangerous levels of radiation are many, many times above normal background radiation and typical 'acceptable' levels of exposure.
"Chief cabinet secretary Yukio Edano has told a press conference that he cannot confirm that the explosion at the nuclear power plant was the reactor, saying details of the incident remained unclear. He said authorities were prepared for the worst emergency but urged people to remain calm and not to listen to rumours. He also asked them to conserve electricity."
Any opinions on what the thing rising up very quickly during the explosion is? I initially thought it was the roof, but I'm wondering now if it isn't actually a flame from burning hydrogen. Ideas?
Can someone provide background information on the type of reactor at Fukusima, it's age, and it's failsafe mechanism. I was under the impression that no modern reactor would sustain criticality in the event of a failure.
It lacks the safety mechanisms of an abwr. Namely even after the control rods are deployed, heat can continue to build up. Hence the plant requires forced cooling, in this case provided by diesel and electric pumps. After the earthquake the diesel pumps failed and cooling was effected by battery power. While the government rushed in new diesel generators, they were not installed in time to prevent the build up of pressure resulting in this explosion.
From wikipedia: "Fukushima I – 1 BWR First criticality: March 26, 1971". So it isn't a "modern" reactor, not sure what the fail safes are but I have read from some sources all the fail safes are older generations which require power.
what I understand now is that the blast at the nuclear plant may have been caused by a hydrogen explosion (pressure) or If nuclear fuel rods overheat and then come into contact with water, this produces a large amount of highly-flammable hydrogen gas which can then ignite. Right?
Can anyone with more knowledge and experience of this confirm?
That's certainly possible, theoretically. However, I'm not sure if those conditions can actually be met (rods should not ever come into contact with water and nothing should be able to ignite the gas, especially not at higher pressure levels).
An attempt to explain the risk to the Fukushima nuclear plants following the earthquake: The plants are designed to shut automatically, which halts the main nuclear fission reaction, but there is a residual amou ntense heat within the system. Back-up generators should kick in to power the coolin mechanisms needed to dissipate that heat - b they fail, as appears to have happened here, temperatures rise. If this isn't stopped, the reactor vessel itself could eventually melt an eak.
Right? Has anybody found any documents if Japan has been notified or warned about these backup systems of these plants? It sound like a design failure to me. (I know nothing about nuclear power plants)
Watching BBC, it seems mainly the walls and roof have been blown out.
The main steel structure is still standing, and the expert in the studio was saying something like there still is a chance of the 3-Mile Island like scenario. That is that the nuclear material is still contained within the core structure.
As I understood it (when discussing it with someone in the know), was that it was likely caused by zirconium in the fuel-rods reacting with water.
This hydrogen should be taken care of, but without (enough?) electrical power levels of hydrogen gas builds up.
This does not mean that containment is broken, or that there is an imminent danger to outsiders. But it is a very serious situation, especially since there seems to be at least two more reactors in similar situations at Fukushima Daiichi.
Come on, there is absolutely no way for a nuclear plant to make a nuclear explosion. Nuclear fuel at high temperature touching the cooling water separates the water in O and H2, which is an highly explosive cocktail, didn't they show you that in high school?
The main danger now is of a fire lifting radioactive material away. This isn't in any case an immediate life-threatening risk, except for the people in the power plant immediate vicinity.
A nuclear explosion? No chance, it will "simply" leak, worst case it catches fire and goes Chernobyl but spreads its radiation over a more populated area, which is probably worse that a nuclear weapon going off.
Head over to Fark, look up whatever the latest thread is. Yes, there are trolls and idiots. There are also knowledgeable people providing useful information. I'm basically refreshing that every few minutes and using it as my baseline for what's going on.
The things we should fear are myocardial infarction [1] and cerebrovascular accident [2]. These are what will probably kill us in developed countries [3]. The good news is that we know how to prevent many of these deaths: regular exercise, not over-eating, not smoking and moderation in alcohol and drug consumption. Other causes of death and ill-health are also reduced by these actions.
Yes, you will likely be death in the next 100 years.
Seriously though the structure that contained the reactor isn't the only thing that protects the reactor (it was at Chernobyl, which is why it went badly) it is also protected by a thick concrete container (which is pretty much what was eventually built around the Soviet reactor) which means that in the event of a meltdown the structure will contain the radioactive stuff.
So in summary: unless you are really close (which you shouldn't be) or have a burning desire to be inside that reactor building you will die of something else entirely (most likely something boring).
No. Even if shit gets real and the reactor goes Chernobyl, Japan is sufficiently far away from the western world that it doesn't matter at all. People weren't concerned about radiation from the nukes in Bikini either.
Still hard to say. Fortunately, the wind is forecast to go out towards the Pacific for the next few days. But if the situation escalates as badly as Chernobyl, enough stuff may get out for everyone to get some.
[+] [-] ck2|15 years ago|reply
There is almost guaranteed significant radiation release.
quote from slashdot:
[+] [-] koski|15 years ago|reply
(EDIT) More from Walt Patterson of Chatham House. He says the presence of the radioactive caesium in the surrounding area does not pose a huge threat to public health in the immediate aftermath of the explosion. "What would be serious is if there was an explosion or fire that lifted this stuff high in the air, meaning it could get carried over a wide area."
[+] [-] bobfunk|15 years ago|reply
http://slashdot.org/~TopSpin
But who knows...
[+] [-] koski|15 years ago|reply
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] foobarbazetc|15 years ago|reply
The reactor DID NOT explode. HN is becoming a bit sensationalist today.
Edit: http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Sy...
Basically, this bit:
The reactor building (the shield wall/missile shield) is also made of steel-reinforced, pre-stressed concrete 0.3 m to 1 m (1–3 feet) thick.
The concrete surrounding the building is now gone (due to excess pressure).
Second edit:
[6:54 a.m. ET, 8:54 p.m. Tokyo] The explosion at Japan's Fukushima nuclear plant was not caused by the nuclear reactor but by "water vapor that was part of the cooling process," Chief Cabinet Secretary Yukio Edano said Saturday. He said no harmful gases had been emitted by the explosion.
[6:44 a.m. ET, 8:44 p.m. Tokyo] Japanese Prime Minister Naoto Kan confirms that the evacuation area around the Fukushima Daiichi nuclear plant has been increased to 20 kilometers. But no one has been harmed by radiation, he says.
Third edit (from the BBC):
1218: It seems clear now from Mr Edano's comments that the nuclear plant building that was blown apart earlier did house a reactor, but the reactor was protected by its metal casing.
1216: Government spokesman Yukio Edano says the pressure as well as the radiation at the Fukushima-Daiichi nuclear plant has fallen following this afternoon's explosion.
So the "explosion" has actually helped the situation.
Fourth edit: Looking like Sendai just got hit with another earthquake. I hope that hasn't caused any more damage to the reactor. http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/us...
Fifth edit: From http://twitter.com/#!/norishikata
"Blast was caused by accumulated hydrogen combined with oxygen in the space between container and outer structure. No damage to container."
"Trend of μ Sv/h of Unit 1 this afternoon. 1,015(at 15:29), blast (15:36), 860(15:40), 70.5 (18:58). After blast, radioactive level lowered."
"TEPCO's efforts to depressurize the container was successful. Additional measures are now taken tonight using sea water and boric acid."
Things are looking up.
[+] [-] uvdiv|15 years ago|reply
"At this point, there has been no major change to the level of radiation leakage outside (from before and after the explosion), so we'd like everyone to respond calmly," Edano said."
http://www.reuters.com/article/2011/03/12/japan-quake-reacto...
Now they are going to flood the reactor container with seawater.
[+] [-] jensnockert|15 years ago|reply
A (what I guess) is a similar explosion happened in the reactor building in TMI, and the risk of an explosion such as this seems to be well known. The reactor building was probably prepared to absorb the explosion away from the containment structures, making it look much worse than it is.
[+] [-] zach|15 years ago|reply
http://www.youtube.com/watch?v=pg4uogOEUrU#t=46s
[+] [-] jensnockert|15 years ago|reply
-----
1. Hydrogen explosion occurred at 15:36 between containment and reactor building of Fukushima Daiichi unit 1. Walls of reactor building were blown out or damaged.
2. It was confirmed that unit 1 containment integrity was maintained.
Explosion was not inside the containment as it is inert.
3. Radiation level at the Fukushima Daiichi site border once increased when containment vent was conducted and reached 1,015 micro Sv per hour around the time when explosion occurred; however, the radiation level turned to decrease after the explosion down to 860 at 15:40 and 70.5 micro Sv per hour at 18:58.
4. Government has agreed to TEPCO decision to fill the entire containment up with sea water. The filling sea water will contain boron. TEPCO started the work for filling up at 20:20.
[+] [-] jensnockert|15 years ago|reply
[+] [-] jensnockert|15 years ago|reply
[+] [-] sophacles|15 years ago|reply
(It just reads like one of those understated but extremely important bits you find in these sorts of alerts :-| )
[+] [-] koski|15 years ago|reply
The plant "may be experiencing nuclear meltdown", Kyodo and Jiji reported before the explosion, while public broadcaster NHK quoted the safety agency as saying metal tubes that contain uranium fuel may have melted.(AFP)
[+] [-] sliverstorm|15 years ago|reply
See http://www.geigercounters.com/Danger.htm for example. Occupational acceptable exposure is 25x that of non-occupational.
[+] [-] JonnieCache|15 years ago|reply
http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsuna...
[+] [-] ajb|15 years ago|reply
[+] [-] uvdiv|15 years ago|reply
(I am not an engineer)
[+] [-] koski|15 years ago|reply
[+] [-] angus77|15 years ago|reply
[+] [-] brg|15 years ago|reply
[+] [-] brg|15 years ago|reply
http://en.wikipedia.org/wiki/Boiling_Water_Reactor
It lacks the safety mechanisms of an abwr. Namely even after the control rods are deployed, heat can continue to build up. Hence the plant requires forced cooling, in this case provided by diesel and electric pumps. After the earthquake the diesel pumps failed and cooling was effected by battery power. While the government rushed in new diesel generators, they were not installed in time to prevent the build up of pressure resulting in this explosion.
[+] [-] hartror|15 years ago|reply
[+] [-] famousactress|15 years ago|reply
[+] [-] mberning|15 years ago|reply
[+] [-] anigbrowl|15 years ago|reply
[+] [-] LogicHoleFlaw|15 years ago|reply
[+] [-] brown9-2|15 years ago|reply
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] user24|15 years ago|reply
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] koski|15 years ago|reply
Can anyone with more knowledge and experience of this confirm?
[+] [-] craigmccaskill|15 years ago|reply
[+] [-] m104|15 years ago|reply
More info: http://www.world-nuclear-news.org/RS_Battle_to_stabilise_ear...
[+] [-] koski|15 years ago|reply
Right? Has anybody found any documents if Japan has been notified or warned about these backup systems of these plants? It sound like a design failure to me. (I know nothing about nuclear power plants)
[+] [-] cskau|15 years ago|reply
The main steel structure is still standing, and the expert in the studio was saying something like there still is a chance of the 3-Mile Island like scenario. That is that the nuclear material is still contained within the core structure.
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] jensnockert|15 years ago|reply
This hydrogen should be taken care of, but without (enough?) electrical power levels of hydrogen gas builds up.
This does not mean that containment is broken, or that there is an imminent danger to outsiders. But it is a very serious situation, especially since there seems to be at least two more reactors in similar situations at Fukushima Daiichi.
(http://www.world-nuclear-news.org/RS_Battle_to_stabilise_ear... also refers to a problem at Fukushima Daini.)
[+] [-] wazoox|15 years ago|reply
The main danger now is of a fire lifting radioactive material away. This isn't in any case an immediate life-threatening risk, except for the people in the power plant immediate vicinity.
[+] [-] hartror|15 years ago|reply
[+] [-] ubernostrum|15 years ago|reply
Head over to Fark, look up whatever the latest thread is. Yes, there are trolls and idiots. There are also knowledgeable people providing useful information. I'm basically refreshing that every few minutes and using it as my baseline for what's going on.
[+] [-] anigbrowl|15 years ago|reply
[+] [-] phreeza|15 years ago|reply
[+] [-] oemera|15 years ago|reply
[+] [-] by|15 years ago|reply
[1] http://en.wikipedia.org/wiki/Myocardial_infarction [2] http://en.wikipedia.org/wiki/Stroke [3] http://en.wikipedia.org/wiki/List_of_causes_of_death_by_rate...
[+] [-] tomjen3|15 years ago|reply
Seriously though the structure that contained the reactor isn't the only thing that protects the reactor (it was at Chernobyl, which is why it went badly) it is also protected by a thick concrete container (which is pretty much what was eventually built around the Soviet reactor) which means that in the event of a meltdown the structure will contain the radioactive stuff.
So in summary: unless you are really close (which you shouldn't be) or have a burning desire to be inside that reactor building you will die of something else entirely (most likely something boring).
[+] [-] adrianN|15 years ago|reply
[+] [-] georgecmu|15 years ago|reply
http://img405.imageshack.us/img405/3245/8m6k8n7f8q7z7.jpg
US West Coast gets the fallout cloud in 10 days.
[+] [-] brazzy|15 years ago|reply
[+] [-] giberson|15 years ago|reply