Japanese earthquake / tsunami discussion

Hotblack Desiato

geetar wrote: »

thats an over exageration.

the current estimates (12000ish) are well under the probable amount.

but realisticly, its probably between 20,000 and 30,000, still an awful amount of people, but not 100,000 by a long shot

AFAIK 12,000 isn't an estimate it's the currently confirmed death toll and that is only going to increase.

Whole towns with thousands of inhabitants have been wiped off the map. The true scale of this will only become known in time and the focus of the authorities at the moment will be on the living not on the dead for whom nothing can be done - and in many cases whose bodies will never be found.

I hope I'm wrong, but I expect the final death toll to be well in excess of what is being reported now.

opinion guy

ninja900 wrote: »

AFAIK 12,000 isn't an estimate it's the currently confirmed death toll and that is only going to increase.

Whole towns with thousands of inhabitants have been wiped off the map. The true scale of this will only become known in time and the focus of the authorities at the moment will be on the living not on the dead for whom nothing can be done - and in many cases whose bodies will never be found.

I hope I'm wrong, but I expect the final death toll to be well in excess of what is being reported now.

It strikes me that there are probably socially isolated people who have been lost from areas where a whole community was lost, and outside of that community no-one will no that particular people even lived in the first place. Very sad I think.

Turtwig

ninja900 wrote: »

No, no it doesn't. You'll find the electronics are a lot more durable than the humans flying them. I did a project on the effects of radiation on semiconductors.

Alpha and beta can't penetrate chip packaging. Gamma mostly just goes straight through (it helps that silicon is such a light element.) Eventually you get atoms knocked out of the crystal lattice and the performance of the device gradually degrades but that's a slow process even under very high dose levels.

Dynamic RAMs are the most vulnerable to bit-flipping from the deposition of charge from gamma or cosmic rays (the latter in the upper atmosphere or in space, the atmosphere shields us) but simple error checking techniques can greatly mitigate this. Spacecraft use special radiation hardened chips but they face a very hostile environment up there - energetic cosmic rays and particles that don't penetrate air to any significant distance. Not what would be encountered in this reactor scenario. Also satellites have to survive in the space environment for several years and are clocking up a radiation dose all that time.

Incidentally the radiation dose that aircraft experience at 40,000ft is significantly higher than on the ground, and they are totally dependent on electronics these days - and will experience this irradiation every time they get up to altitude (cosmic rays.) Concorde at 60,000ft experienced about twice as much, but was up there for less than half as long per flight due to going more than twice as fast it did carry a radiation meter in case of solar flare activity but that was to protect the passengers and crew by getting down to a lower altitude if a solar flare occurred.

Well, I'm gonna have to research this further.:) But, at the time of Chernobyl the Russians tried using robots to help in the clean up. These robots had a very short life span due to the radiation. There were also significant amounts of damage reported to the choppers engines. I don't think the semiconductor devices electronics are what's crucial to keep a helicopter afloat but like I said I gotta do more research on this.

Regarding re-Criticality, tonnes of people are surprised by that but Tepco has said that's its possible and they know their fuel rods better than anyone else.

andrew

ninja900 wrote: »

It's not possible that the fuel ponds go critical. The fuel isn't enriched enough and is not in close enough proximity to go critical even if it totally melts down. FFS, even inside the reactor it can't sustain a chain reaction without the moderator - WATER. No water - no reaction.

Given the fuel rods were formerly in reactor 4, and are only out of there for maintainence, how is it that they're not enriched enough for the reaction to start again? With regard to the going critical if it melts, I was under the impression that a moderator is only needed to enhance the efficiency of a nuclear reactor - fast neutrons can still cause fission, they just do so less than slow neutrons. This publication (a comprehensive review of criticality accidents which have occurred) indicates that this is the case, and that it's surprisingly easy for fission to occur, given concentrations of Uranium which are high enough.

IANA Engineer/Physicist though, so I'm open to correction.

Hotblack Desiato

andrew wrote: »

Given the fuel rods were formerly in reactor 4, and are only out of there for maintainence, how is it that they're not enriched enough for the reaction to start again?

They were far more closely packed together in the reactor, and had the benefit of a moderator in the reactor.

With regard to the going critical if it melts, I was under the impression that a moderator is only needed to enhance the efficiency of a nuclear reactor - fast neutrons can still cause fission, they just do so less than slow neutrons.

Yes they can but obviously if you are relying on fast neutrons for uranium fission (which is much less efficient) your critical mass goes way up (or alternatively you need to concentrate your fuel into a much smaller area, which has the same effect.)

Good design would ensure that the physical arrangement of the fuel pond could never become critical. The science regarding this was well known by 1950 never mind 1970 when these reactors were designed and built.

www.orau.org/ptp/Library/accidents/la-13638.pdf"]This publication (a comprehensive review of criticality accidents which have occurred) indicates that this is the case, and that it's surprisingly easy for fission to occur, given concentrations of Uranium which are high enough.

IANA Engineer/Physicist though, so I'm open to correction.

158 pages is a lot to read through right now although many of those incidents appear to involve Pu/HEU in solution in reprocessing plants or labs researching into reprocessing, if you concentrate highly enriched nuclear materials in solution it is easy to get into a criticality situation. We are talking about solid materials here and low enrichment.

I'm by no means an engineer either although I did study nuclear physics 20-odd years ago and my final year physics project involved studying the effects of radiation - although I've never worked in that field.

andrew

ninja900 wrote: »

They were far more closely packed together in the reactor, and had the benefit of a moderator in the reactor.



Yes they can but obviously if you are relying on fast neutrons for uranium fission (which is much less efficient) your critical mass goes way up (or alternatively you need to concentrate your fuel into a much smaller area, which has the same effect.)

Good design would ensure that the physical arrangement of the fuel pond could never become critical. The science regarding this was well known by 1950 never mind 1970 when these reactors were designed and built.





158 pages is a lot to read through right now although many of those incidents appear to involve Pu/HEU in solution in reprocessing plants or labs researching into reprocessing, if you concentrate highly enriched nuclear materials in solution it is easy to get into a criticality situation. We are talking about solid materials here and low enrichment.

I'm by no means an engineer either although I did study nuclear physics 20-odd years ago and my final year physics project involved studying the effects of radiation - although I've never worked in that field.

Oh I didn't expect you to read it of course! It's just I didn't wanna cite the Wiki page on criticality accidents because that focuses on incidents with the 'demon core' and all that which aren't really similar. I thought that maybe molten uranium would be similar to uranium in solution you see, since it's dense, and could perhaps flow into a shape with the right geometry. But I can see now why that's probably not the case.

Hotblack Desiato

Malty_T wrote: »

Well, I'm gonna have to research this further.:) But, at the time of Chernobyl the Russians tried using robots to help in the clean up. These robots had a very short life span due to the radiation.

First of all, we don't know how advanced late 80s Soviet robot technology was - but we can guess. Politically it was expedient to blame any failures on the radiation rather than their technology.

Secondly these robots were sent in very close to the remains of the core, which had no containment at all.

Thirdly the less sophisticated their electronics were (i.e. the larger the transistors / fewer transistors per chip) the less the effect of radiation would be.

There were also significant amounts of damage reported to the choppers engines. I don't think the semiconductor devices electronics are what's crucial to keep a helicopter afloat but like I said I gotta do more research on this.

What sort of damage? a cite would help.

It could be as simple as flying it into an air mass warmed by the reactor - which means loss of lift (less dense air) and therefore higher power settings needed to maintain altitude, while at the same time the air temperature hitting the high pressure turbine increases. It's conceiveable that this could melt some of the turbine blades. At high power the turbine blades in a jet engine can be quite close to melting point.

Regarding re-Criticality, tonnes of people are surprised by that but Tepco has said that's its possible and they know their fuel rods better than anyone else.

Cite? and I'd be wary of the possible effects of bad translation here.
It really would be bad design if the fuel is not spaced far enough apart to make criticality impossible.

andrew

ninja900 wrote: »

Cite? and I'd be wary of the possible effects of bad translation here.
It really would be bad design if the fuel is not spaced far enough apart to make criticality impossible.

I think the worry is that the explosions and water dumps and lack of water may have led to the fuel bundles falling over and on top of one another; that in general, their geometry has been disturbed.

Overheal

gbee wrote: »

Some of the fear is down to the official media from Japan over their mix up with

µ = micro as in µSv microsievert
m = milli as un mSv millisievert

I've seen and heard NHK-TV saying that instantly lethal doses of radiation had been released when in fact the doses were very, very, very very much LESS.

They did not say this like I've just put it, they said because they took a microsievert reading and reported it in either sieverts or millisiervets making the dose tens of thousands the level of reality.

But any hack looking for sensation might see or hear only the huge figure and think, Armageddon.

and THEN try explaining the Metric System to a panicked american populace :rolleyes:

Hotblack Desiato

andrew wrote: »

I think the worry is that the explosions and water dumps and lack of water may have led to the fuel bundles falling over and on top of one another; that in general, their geometry has been disturbed.

OK, but that should have been taken into account. It's hard to see how an arrangement of the fuel as dense as it would have been inside the reactor could occur - and even then there would be no water to act as a moderator.

Thrill

ninja900 wrote: »

Cite? and I'd be wary of the possible effects of bad translation here.
It really would be bad design if the fuel is not spaced far enough apart to make criticality impossible.

I remember hearing TEPCO mention the possibility in a press conference. I cant find the video of the presser but its mentioned here........


http://www.youtube.com/watch?v=JBxJ1PqzqNE

also
http://www.dailykos.com/story/2011/03/16/956962/-TEPCO:-The-possibility-of-re-criticality-is-not-zero

Tokyo Electric Power Company (Tepco) has warned:

The possibility of re-criticality is not zero.

Cooler, older spent fuel rods in the fuel pool adjacent to the reactor are packed at a density designed for lower levels of heat production to save on costs and space. The water in spent fuel pools is treated with borate to adsorb neutrons and poison nuclear reactions that could cause an accidental, unintended criticality event in the spent fuel pool. Because untreated water acts as a moderator, (which slows neutrons, increasing the probability of induced fission) re-criticality is a theoretical possibility if borated water is lost and replaced with boron free water.

http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents

Possibility of criticality in the spent fuel pool

At approximately 14:30 on 16 March, TEPCO announced its belief that the storage pool—which is located outside the containment area[175]—may have begun boiling, raising the possibility that exposed rods would reach criticality.[33][176] BBC commented that criticality would not mean a nuclear bomb-like explosion, but a sustained release of radioactive materials would be a possible scenario.[33] Around 20:00 JST it was planned to use a police water cannon to spray water on unit 4.[177]

Yakult

whats the news on the nuclear plant? Is it stabilized?

andyseadog

Yakult wrote: »

whats the news on the nuclear plant? Is it stabilized?

x2.

looks like theres been nearly 30 pages of thread since i last checked this morning. i'd love to read it all, but :pac:

a brief summary if anyone's awake would be great

Overheal

they built a new power line to connect the plant back to the grid; will complete grid hook-up of reactor 2 as soon as water-cannon operations stop on reactor 3. Should hopefully happen any time now, and hopefully the primary cooling in reactor 2 will be back online, they will then, logically, begin restoring grid power to the other reactors.

Mr Benevolent

TEPCO suggests burying the plant as an option.

maquiladora

Not sure if something new has prompted this or if it just based on what happened this week :

Japan nuclear safety agency says level 5 incident at Fukushima reatcors no. 1, 2, 3, raised from level 4 - Reuters

gbee

5:00pm local time, water seems to have reached fuel containment pool.
Radiation levels 20mSv/hr at plant. Gates 3.3mSv/hr
Incident level raised to level ? according to international regulations

My bad ~ NHK News says level from 4 to 5.

Run_to_da_hills

MOX plutonium fuel used in Fukushima's Unit 3 reactor two million times more deadly than enriched uranium. One of the reasons why so much effort is put into cooling this reactor.

MOX plutonium fuel used in Fukushima's Unit 3 reactor two million times more deadly than enriched uranium

Sources for the above:
http://www10.antenna.nl/wise/index.html?http://www10.antenna.nl/wise/469-470/6.html#Chap_6_2

http://www.npr.org/2011/03/16/134600825/plutonium-in-fuel-rods-cause-for-concern?ps=cprs

uprising2

'Suicide squad' mans Japan's nuclear plant
Tokyo: Personnel attempting to cool down Japans stricken Fukushima plant have been dubbed a "suicide squad" with their families accepting their fate like a "death sentence".
The Sankei Shimbun newspaper called the police team "Kes****ai"- meaning a "unit that expects to die".
http://www.ndtv.com/article/world/suicide-squad-mans-japans-nuclear-plant-92619


"Chernobyl solution" may be last resort for Japan reactors.
TOKYO, March 18 (Reuters) - A "Chernobyl solution" may be the last resort for dealing with Japan's stricken nuclear plant, but burying it in sand and concrete is a messy fix that might leave part of the country as an off-limits radioactive sore for decades.
http://af.reuters.com/article/energyOilNews/idAFL3E7EI0IJ20110318

Frantic Repairs Go On at Plant as Japan Raises Severity of Crisis
As the crisis seemed to deepen, Japan’s nuclear safety agency raised the assessment of its severity from 4 to 5 on a 7-level international scale. Level 4 is for incidents with local consequences while level 5 denotes broader consequences. It was not immediately clear why the action had been taken.
http://www.nytimes.com/2011/03/19/world/asia/19japan.html

Not looking too good, I was actually wondering will people step forward and offer their lives to try and save others, and it seems they have, brave people, I just hope their sacrifice is not in vain.

Thrill

: Around 50 tonnes of water were sprayed in about 40 minutes onto the storage pool at the reactor in Fukushima on the second day of the operation.

Solair

I suspected that there might be some kind of serious damage to those cooling pools given that they're concrete and the earthquake was so severe.

It seems that various US nuclear experts have the same suspicions :eek::eek::eek::eek:

That assessment by U.S. Nuclear Regulatory Commission officials is based on the sequence of events since the earthquake and information provided by key American contractors who were in the plant at the time, said government officials familiar with the evaluation. It was compelling evidence, they said, that the wall of the No. 4 reactor pool has a significant hole or crack

"My intuition is that this is a terrible situation and it is only going to get worse," he said. "There may not be any way to deal with it."

See LA Times article:

http://www.latimes.com/news/nationworld/world/la-fg-japan-quake-wrapup-20110318,0,2262753.story?page=1

Thrill

The IAEA can confirm the following new information regarding the temperatures of the spent nuclear fuel pools at Units 4, 5 and 6 at Fukushima Daiichi nuclear power plant:

Unit 4
13 March, 19:08 UTC: 84 °C

Unit 5
17 March, 03:00 UTC: 64.2 °C
17 March, 18:00 UTC: 65.5 °C

Unit 6
17 March, 03:00 UTC: 62.5 °C
17 March, 18:00 UTC: 62.0 °C

Thrill

Japanese authorities have informed the IAEA that new INES ratings have been issued for some of the events relating to the nuclear emergency at the Fukushima Daiichi and Daini nuclear power plants.


Japanese authorities have assessed that the core damage at the Fukushima Daiichi 2 and 3 reactor units caused by loss of all cooling function has been rated as 5 on the INES scale.


Japanese authorities have assessed that the loss of cooling and water supplying functions in the spent fuel pool of the unit 4 reactor has been rated as 3.

Japanese authorities have assessed that the loss of cooling functions in the reactor units 1, 2 and 4 of the Fukushima Daini nuclear power plant has also been rated as 3. All reactor units at Fukushima Daini nuclear power plant are now in a cold shut down condition

IAEA

star gazer

As well as the upgrade on the nuclear incident scale from four to five, Japan is still coming to terms with the huge human cost of the earthquake and tsunami. BBC

Meanwhile, further heavy snowfall overnight all but ended hopes of rescuing anyone else from the rubble after the 9.0-magnitude quake and tsunami.

Millions of survivors have been left without water, electricity, fuel or enough food; hundreds of thousands more are homeless.
According to the latest figures, 6,405 people are dead and about 10,200 are missing.

On Friday, people across Japan observed a minute's silence at 1446 (0546 GMT), exactly one week after the disaster.

Canis Lupus

The Register has an article here. HERE

I think the note he puts at the end sums it all up "As one who earns his living in the media these days, I can only apologise on behalf of my profession for the unbelievable levels of fear and misinformation purveyed this week. I have never been so ashamed to call myself a journalist."

vibe666

Canis Lupus wrote: »

The Register has an article here. HERE

I think the note he puts at the end sums it all up "As one who earns his living in the media these days, I can only apologise on behalf of my profession for the unbelievable levels of fear and misinformation purveyed this week. I have never been so ashamed to call myself a journalist."

there's also a link in the reg article to an article that includes a letter from Ted Rockwell who is described as the "guy who wrote the book on nuclear safety" condemning the scaremongering and bullsh1t surrounding the incident.

http://atomicinsights.blogspot.com/2011/03/ted-rockwell-fukushima-its-not-about.html

FUKUSHIMA: IT’S NOT ABOUT RADIATION, IT’S ABOUT TSUNAMIS

A lot of wrong lessons are being pushed on us, about the tragedy now unfolding in Japan. All the scare-talk about radiation is irrelevant. There is no radiation danger, there will be no radiation danger, regardless of how much reactor melting may occur. Radiation? Yes. Danger? No. Life evolved on, and adapted to, a much more radioactive planet, Our current natural radiation levels—worldwide—are below optimum. Statements that there is no safe level of radiation are an affront to science and to common sense. The radiation situation should be no worse than from the Three Mile Island (TMI) incident, where ten to twenty tons of the nuclear reactor melted down, slumped to the bottom of the reactor vessel, and initiated the dreaded China Syndrome, where the reactor core melts and burns its way into the earth. On the computers and movie screens of people who make a living “predicting” disasters, TMI is an unprecedented catastrophe. In the real world, the molten mass froze when it hit the colder reactor vessel, and stopped its downward journey at five-eights of an inch through the five-inch thick vessel wall. And there was no harm to people or the environment. None.

Yet in Japan, you have radiation zealots threatening to order people out of their homes, to wander, homeless and panic-stricken, through the battered countryside, to do what? All to avoid a radiation dose lower than what they would get from a ski trip.

The important point for nuclear power is that some of the nuclear plants were swept with a wall of seawater that may have instantly converted a multi-billion dollar asset into a multi-billion dollar problem. That’s bad news. But it’s not unique to nuclear power. If Fukushima were a computer chip factory, would we consider abandoning the electronic industry because it was not tsunami-proof? It would be ironic if American nuclear power were phased out as unsafe, without having ever killed or injured a single member of the public, to be replaced by coal, gas and oil, proven killers of tens of thousands each year.

Moreover, the extent and nature of the damage from seawater may be less than first implied. Rod Adams, a former nuclear submarine officer, who operated a nuclear power plant at sea for many years, says that inadvertent flooding of certain equipment with seawater was not uncommon. He includes electronics-laden missile tubes. “We flushed them out with fresh water,” he said. “Sometimes we had to replace insulation and other parts. But we could ultimately bring them back on line, working satisfactorily.”

The lessons from Japan involve tsunamis, not radiation.

Theodore Rockwell
Member, National Academy of Engineering

Dr. Rockwell’s classic 1956 handbook, The Reactor Shielding Design Manual, was recently made available on-line and as a DVD, by the U.S. Department of Energy.

Rob A. Bank

Canis Lupus wrote: »

The Register has an article here. HERE

The Register has another article here. http://www.theregister.co.uk/2011/03/14/fukushiima_analysis/

"Fukushima is a triumph for nuke power: Build more reactors now!"


Great to see their unbiased balanced journalism...

:-/

Canis Lupus

Rob A. Bank wrote: »

The Register has another article here. http://www.theregister.co.uk/2011/03/14/fukushiima_analysis/

"Fukushima is a triumph for nuke power: Build more reactors now!"


Great to see their unbiased balanced journalism...

:-/

You do realise The Register likes to use tongue in cheek headlines? The article itself just reinforces the later one. IE everyone needs to calm down.

Thrill

An unnamed diplomat says Japan's radioactive fallout has reached southern California but first readings are "a billion times beneath levels" that would be considered a threat to health, AP reports.

vibe666

Thrill wrote: »

An unnamed diplomat says Japan's radioactive fallout has reached southern California but first readings are "a billion times beneath levels" that would be considered a threat to health, AP reports.

it may have just been the radiation leaking from the banana in his lunchbox. :pac:

i'm not surprised he wanted to remain unnamed either.