2 Japanese nuclear reactors may be in meltdown

[DavidU]

This is not good at all.
http://edition.cnn.com/2011/WORLD/asiapcf/03/12/japan.nuclear/?hpt=T1

[gary]

Hi David,

Thanks for the link to the story.

The links in this post here have additional information -
http://www.iceinspace.com.au/forum/showpost.php?p=698082&postcount=51

The detection of the cesium 137 as a "smoking gun" is of a concern and let's
hope if melting has occurred that it is limited and contained.

As I mentioned, as we all relax here on a Sunday afternoon, spare a thought for the workers
who at this very moment will be in there trying to stabilize the reactors. One is reported dead,
two missing and several others injured. Tomorrow morning, when the alarm clock sounds,
many of us will groan about having to get up and go to work. But how many of us would be
willing to take on the jobs that these guys must be battling with right now?

[renormalised]

They believe it maybe contained....let's hope so, otherwise having 2 breached reactors will be the icing on top of a very bitter tasting cake.

[toc]

I came back from a bike ride with my daughter, and ABC24 host announced 'there has been a nuclear explosion in Japan'. :scared: I nearly fainted. Thankfully it was just an poor turn of phrase, but its still a tragic situation.

[Steffen]

Amongst the hysteria and misinformation spread by the mainstream press I found this quite informative:

http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/

Cheers
Steffen.

[CraigS]

Good rational article, there Steffen.

Thanks kindly for that.
:)
There seems to be one bullet point missing from the end.
If I can believe the newspapers, it doesn't seem to have worked out too well for a few of the workers at one of the plants .. I read somewhere that they are receiving treatment for radiation burns … (maybe).

Cheers

[steve000]

May i suggest reading
http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors

scroll down a little and read the HUGH story

[casstony]

Governments regularly demonstrate that we can't trust them so is it any wonder that the populace gets a little worried at times like this.

[CarlJoseph]

Another article to throw into the mix. This one describes how nuclear power plants work.

http://www.boingboing.net/2011/03/12/nuclear-energy-insid.html

[Ric]

Very interesting links guys.

Thanks

[ballaratdragons]

New announcement states 3 reactors now possibly at meltdown danger.

[bartman]

Thanks Steffen,
Thats great reading!
Bartman

[CraigS]

Ok … so is this latest report in the newspapers (SMH) accurate or not ?



Full exposure of the rods is a major issue … something to be very worried about.

Cheers

[xelasnave]

Why not build your own reactor?
http://www.youtube-nocookie.com/watch?v=i0TlECFbjvM&feature=related

Certainly a melt down is serious but modern reactors have a "drip tray" to make them absolutely safe;)
alex:):):)

[CraigS]

He's baaack ! (Hi Alex).

Steffan's paper described this aspect ..

Cheers

[xelasnave]

Yes indeed Craig and I must say I found it all most comforting. I have been anti NP in the past only because I feel humans sometimes make mistakes and things dont always go according to the plan however with each new disaster we learn more as to how to avoid the disaster we find ourselves in and the drip tray is yet another advance for the industry.

I think all the reactors have been shut down and it is only residual heat they need to dissipate and although they suspect a rod or two may have suffered a little melting it is not all that bad, it could have been much worse....certainly I am hopeful that atmospheric contamination does not become a concern and that the casualties of plant workers is minimal.

I can not imagine how it must be for those poor souls in Japan or Christchurch having to come to grips with the devastation all around them and yet somehow plan for a future where all is normal.

alex:):):)

[CraigS]

.. and then ..


What a mess …. its all just terrible ..

[xelasnave]

140 minutes:eyepop:

That would suggest major melting of the containment jackets as I think 50 minutes is their time limit...:shrug:

The day before the quake I was arguing with a chap about NP and he said it was a good idea for Australia and I said yes maybe but when things go wrong they go wrong in a big way ...but I did not think a real life example of my fears would present in such a horrible way...

All of this is so very sad.

I thought I was personally having a bad time of it..flood problems, car smashed, car near stolen and trashed, health issues etc but looking around I cant complain my difficulties are nothing in comparison.

alex:):):)

[gary]

As Alex mentioned, all reactors reportedly successfully SCRAM'd when the
earthquake was detected.

A 'SCRAM' involves the rapid insertion of the reactors control rods which
absorb neutrons and moderate the fission reaction.

Immediately after the control rods are inserted, the core is still at high temperatures for some time
due to the natural decay of fission products. It is then vital to cool the core by continually pumping cool
water through it.

Unfortunately the emergency coolant systems failed undoubtedly due to the earthquake.
However, workers have been pumping sea water through the core.

The temperatures though are sufficiently high that the water's hydrogen becomes
disassociated with the oxygen. The explosions have come from the hydrogen
igniting.

When a running reactor has been shutdown due to a SCRAM, the fission
reaction is largely stopped but some heating sttill occurs due to natural
radioactive decay of the fission products. If the coolant system has been kept operational,
then after the first 72 hours the core will have cooled to a point to
become more manageable.

However, if the core is not kept surrounded by fresh coolant during that
first 72 hours for an extended period of time, then the rods will be sufficiently
hot that a meltdown can occur.

When a meltdown occurs, the steel containment vessel is designed to try and
prevent the molten mass from burning its way through the bottom.

NHK report one of the reactors apparently had the rods exposed for half of
their length for 148 minutes, so a partial meltdown might have taken place.
However, 72 hours have passed for the reactors that have been flooded with
seawater cooling, so hopefully the risk of a full meltdown has passed.

NHK just now report that after the most recent explosion that the radiation levels
were 10,000 times higher than background and that the operators have been evacuated.
There is a concern as to whether the containment vessel has been damaged.

[Trixie]

well I hope these ones have a "drip tray"... and its not cracked...

[gary]

Looking at NHK weather report, winds are predominantly prevailing West to
East 10 to 18 km/h and not to expected to strengthen in the next 24 hours.

So hopefully the winds will blow some radiation out to the Pacific.

Cold front coming in and rain and snow predicted first in the west and later on the
east coast.

TEPCO report via NHK that as at 12:29 AEST, "half the rods are still exposed" on No. 2 and that "they cannot deny
that they may be melting".

TEPCO report radiation levels around the reactor reached 8 times legal levels for a person to be exposed to over one year.
It has since gone down and they are investigating "why the radiation levels are fluctuating so much".

Workers at No 2 that were asked to leave for safery reasons do not include those who are actively attempting to
cool the reactor.

[MrB]

ahaaa

[Octane]

I stayed up last night reading the links on how reactors work -- very enlightening. Thanks for posting the blog link and BoingBoing link.

It's just utterly horrific what's happened in Japan. Nature can be a cruel mistress.

H

[DavidU]

There is now a fire in a 4th reactor.

[CraigS]

It seems inconceivable that the cooling system design was vulnerable to tsunami damage in an earthquake prone region of the world …

I guess we'll find out eventually (perhaps, too early to know), but exactly in what part of the cooling systems did the water ingress cause the problems ?

(Perhaps a rhetorical question).

[mswhin63]

I think it was mentioned earlier that it had knocked out all the diesel generators to run the pumps. They tried to truck in some pumps which also failed or were not able to come in.

[CraigS]

Hmm .. it wouldn't seem to be that difficult to protect diesels from water ingress .. (that's if someone thought of it, in the first place, I suppose).

[Steffen]

There is no risk of a "China Syndrome", because China doesn't lie opposite of Japan… ;)

Cheers
Steffen.

[MrB]

It would be the "Off-the-coast-of-Argentina Syndrome" or "South Atlantic Ocean Syndrome"

[gary]

NHK report that the explosion in No 3. was likely caused by spent fuel
rods being exposed to air.

Once fuel rods are spent, they are removed from the reactor by crane and kept
submerged in a concrete pool filled with water near the top of the reactor vessel.
Since the spent rods take three to four years to cool, it is important that cold
water is continually pumped in and circulated around them.

The pumping system failed due to the power outage and the spent rods became
partially exposed to air and hydrogen was produced which later ignited.

So just as the integrity of the main reactors vessels is paramount, the integrity
of the pools that hold the spent rods is also vitally important.

Unfortunately wind directions around the crippled reactors is westward.

[CraigS]

Gary;

This couldn't get much uglier !!

Rods being exposed to air ??

[casstony]

Perhaps reactors should only be built on stable continents, away from tsunamis, away from water catchments, near an emergency gravity fed water supply, away from regulatory failure................. or maybe we should steer more taxes toward developing more competitive solar technology which people would adopt because it made financial sense.

[gary]

Hi Craig,

It's not a good day.

So not only will a battle being going on to keep the rods inside the reactors cool,
there is a second battle front which is to ensure that the rods that have been spent
and are outside the reactors themselves remain cool as well.

NHK reports that one of the radiation leakage incidents may have been as a result of
the spent rods becoming exposed in the pool. These were associated with a reactor
that the NY Times reports had been under refurbishment for months before the
quake. The NY Times reports that when the spent rods become exposed,
"That is almost as dangerous as the fuel in working reactors melting down,
because the spent fuel can also spew radioactivity into the atmosphere."

What is sobering are the NHK reports of the radiation levels in parts of the
plant facilities themselves where at one point it peaked at 400 millisieverts an hour.
The NY Times suggest that 75 minutes exposure to those levels will result
in severe radiation sickness. NHK reported that exposure to 500 millisieverts for
two hours would result in certain death.

Levels in the areas outside the plants were significantly lower. However, one would have
to be severely concerned for the workers inside the plant who are trying to
stabilize the various events they are dealing with. Many of these would be experts
in their areas and one would only assume many will be totally aware of the peril
they face. Heroes? I for one think by any definition of the word. All we can do is
wish them good luck.

[CraigS]

Yes Gary;

I was thinking that the source information for all these reports we keep getting, must be coming from somewhere close to the problems.

All I keep think about is that dreadful scene from the movie K-19.

Methinks the political head responsible for Japanese Energy should be on suicide watch, also.

Its overwhelmingly sad and shocking.

I just can't wrap my mind around how the engineering has failed them !
So many minds involved in the design of these plants for so many years … all the technology .. and yet a simple thing like protecting the diesels from water ?? There's got to be much more to it all than this …

[toc]

I remember reading that the Germans came up with a reactor design that involved carbon spheres to isolate the fuel, and made it impossible for a meltdown to occur. Might have dreamed it though.

EDIT: Found it on Wikipedia:

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

Looks like it has problems as well...

[casstony]

There must be some way to get nuclear energy safetly. Maybe we could have the reactor out in space and transport the energy produced to Earth. I know we could figure it out if we just put our minds to the task.

[CraigS]

Advances will happen as a result of incidents like this.

This is how technological progress occurs.

Quantum leaps in this area represent higher risk.

I'd still like to understand more about what has actually happened over there.
I have doubts that we're getting the full (& accurate) picture.

Nuclear is here to stay.

[GrahamL]

Tony from the replys in stephens link last page.

[Rob_K]

We already have one - it's called the Sun. ;)

Cheers -

[TrevorW]

Lets not forget they've survived horrific radiation fallout before, they can do it again

[casstony]

Exactly. Why build them on Earth when we already have more available energy than we need. We're on the cusp of having commercially competitive solar energy - a modicum of political will would probably get us there. Solar panels either need to be more efficient or very cheap to produce, or both.

Instead of putting money into research pollies dream up complicated trading schemes. They won't be happy until they have a whole herd of white elephants.

[casstony]

I'm not completely against nuclear power Graham, but I'm annoyed that our glorious leaders seem to look past the bleeding obvious, ie. that great nuclear furnace in the sky that dumps enormous amounts of energy upon us. Even when they do notice it they waste money subsidising inefficient technology when the money could be put to better use.

[TrevorW]

Look it's not politically convenient

we could power Oz by the sun, wind and waves, we get more sun than nearly any other country so why don't we

we could stop burning coal and retrain those people to work in the alternative power industries

the same as we could stop forrestry in old growth regions

but it's not politcally convenient to do so

if a PM and some pollies regardless of what party had the gumption to make tough decisions for this country and stuck by them then things would be different

carbon tax and solar power rebates are just piecemeal efforts and political niceties that force the onus back on the general population while industry prospers at our expense

why are we paying more for petrol now that when fuel was running at $110 a barrell at the height of the gulf war how soon we forget and how easily we are manipulated

[Jen]

:shrug: scary stuff i have to stop watching it on the TV its doing my head in :sadeyes:

[[1ponders]]

As Mods, we realize that it will be difficult to keep political discussion out of this thread but we would respectfully ask that such discussion stay to the topic at hand, the nuclear emergency, and not fall into political "speculation".

thanks

[gary]

In an article in today's New York Times, reporters William J. Broach and Hiroko Tabuchi
report on the concerns over the pools holding the spent fuel rods.



The article quotes David Lochbaum, a nuclear engineer at the Union of Concerned Scientists, that
whereas the reactors are in thick walls, that "the spent fuel of Reactors 1 and 3 is out
in the open.”

The article also quotes a worrying 1997 study conducted by the Brookhaven National
Laboratory on Long Island that made some estimates on the hypothetical number
of fatalities that could occur within a given radius if a facilities spent fuel rods are
uncovered in the cooling pool.

The hope is that one way or the other, water will be able to be put into the pools to get them filled
before they boil dry.



Full article here -
http://www.nytimes.com/2011/03/16/world/asia/16fuel.html?hp

[Steffen]

What does my head in is that the press goes berserk about the nuclear threat and hypothetical death and illness while at the same time actual dead bodies are piling up in Japan, measuring 2500+ already and counting. What's wrong with people?

Cheers
Steffen.

[CraigS]

Back to the engineering of it all, this article turned up in Physorg this morning
Fukushima triggers new look at mega-quake threat (http://www.physorg.com/news/2011-03-fukushima-triggers-mega-quake-threat.html)



The last statement hooks up with my Science Forum thread which is turning out to highlight that regardless of how the media seems to imply that science can predict the nature of earthquakes (and some scientists even seem to be attempting to answer such questions), the fundamental unpredictability of earthquakes remains as a fact in science.

In this instance, scientists made estimates (as an input into the engineering process), and they underestimated the probability of big quakes along a tectonic plate subduction zone.

However, the tsunami, (which caused all of this), is more predictable. The size of the tsunami on the other hand, is related to the nature of the quake, and where it occurs.

At the moment, I do believe that it would not be a big ask of engineers, to make sure the diesel backups are at least protected against water intrusion, for the subset of reactors in question.

Cheers

[Kal]

The NY times report is accurate, but the NHK report that 500mSv for 2 hours would result in certain death is inaccurate. 500mSv for 2 hours = 1 Sievert exposure, which you can correlate with the chart below, or verify with the link provided, as to the probable results.

http://www.physics.isu.edu/radinf/risk.htm

1 Sievert = 100 rem


At low doses, such as what we receive every day from background radiation, the cells repair the damage rapidly. At higher doses (up to 100 rem), the cells might not be able to repair the damage, and the cells may either be changed permanently or die. Most cells that die are of little consequence, the body can just replace them. Cells changed permanently may go on to produce abnormal cells when they divide. In the right circumstance, these cells may become cancerous. This is the origin of our increased risk in cancer, as a result of radiation exposure.
At even higher doses, the cells cannot be replaced fast enough and tissues fail to function. An example of this would be "radiation sickness." This is a condition that results after high doses to the whole body (>100 rem), where the intestinal lining is damaged to the point that it cannot perform its functions of intake of water and nutrients, and protecting the body against infection. This leads to nausea, diarrhea and general weakness. With higher whole body doses (>300 rem), the body's immune system is damaged and cannot fight off infection and disease. At whole body doses near 400 rem, if no medical attention is given, about 50% of the people are expected to die within 60 days of the exposure, due mostly from infections.
If someone receives a whole body dose more than 1,000 rem, they will suffer vascular damage of vital blood providing systems for nervous tissue, such as the brain. It is likely at doses this high, 100% of the people will die, from a combination of all the reasons associated with lower doses and the vascular damage.

[xelasnave]

Notwithstanding Steffen's comment about an inappropriate focus not upon the people who have lost their lives I must say I hold grave concern for the future impacts of this crisis. WE can not change the recent past and it is not inappropriate to dwell upon a sad future.


AND it is impossible to separate the politics from this disaster. It is the politics that serves us the future of a world less safe than we would like.

I was disgusted to see our old mate Ziggy Z still offering straight faced reassurance that NP is all good as if nothing of consequence was happening and if is happening we should trust in the NP vision of clean power.

Are humans so arrogant that they can not grasp that notwithstanding their best efforts and their best laid plans that accidents do happen.

The reason accidents are so named is to indicate the occurrence of an unforeseen result and the best of science or engineering simply can never prevent an accident and are only left wringing their hands after each disaster.

Japans experience, where their history dictates earthquakes are the norm, has placed them well prepared for accidents yet accidents are not being managed such that all is remotely satisfactory. Can we not accept the fact that irrespective of our greatness the best of plans can be inadequate.

Np is a most wonderful resource but maybe we should limit its application to space travel to places where we receive no Sun and there is simply no alternative power source and any accident will not impact on all humanity. AND even that is not without risk as the vehicle leaves our planet.

We have all heard that we breath the same molecules that Hitler or other villains breathed throughout history so I ask how long will it be before all of us breath air contaminated via any of these accidents.

The NP lobby has sidelined coal for years as something to fear pushing their "brand" as being most wonderful as it will saves the polar bears etc... what nonsense we do accept when it is pushed upon us from vested interests unconcerned with human welfare and only with their focus upon profit.

I read today that all over folk are getting their NP plants "checked" as if you can fence a cow once it has run off thru the open gate and trampled the neighbors garden. The NP cow can never be safely and certainly fenced and will always from time to time cause damage to the neighbors lands.

I feel upset I am driven to comment on what could be called a political issue but it is really an engineering an science issue.... it is the politics that drives engineers and scientists to suggest they can do the impossible feat of predicting accidents and without diminishing their abilities clearly no human can foresee everything.


alex:):):)

[casstony]

Having worked for 20 years in heavy industry I can say that the risk/reward equation is always in flux. When profits are high the emphasis on safety is high. When profits are skinny (or non-existent) plant maintenance is reduced and short-cuts are taken with operating procedures - management works within a budget for a particular period and maintanence is delayed if money is not available in a particular period.

I searched for TEPCO's profit results for the last few years:
FY MARCH 2008, 2009, profits were negative.

That's not proof of anything in particular, but whether or not financial issues contributed to the current problems needs to be investigated.

[CraigS]

My thoughts are with the people of Japan in this matter .. in exactly the same way, my thoughts were with the cyclone and flood victims, recently.

They'll get through this, and their sacrifices will again benefit everyone else in this world. I admire their resiliency, social achievements and technological advances.

These people are fighters, and they will show us all how it is done.

[xstream]

An excellent article here (http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/) from BraveNewClimate.

Certainly worth taking the time to read!

[mental4astro]

My 2c worth:

The day I see the 'spin doctors', their lap dogs the politicians, and their collective families at these reactors with a bucket and spade to do the cleaning up, and not buggering off somewhere 'safe', only then should anyone feel 'safe'.

To say that an increase of 20x the background radiation is still 'safe', is outrageous!

Are we so gulable!

It's all about money, money, money. Nothing more. :( :mad2:

God help the Japanese people, a third time. And all of us.

[Ric]

If it does go pear shaped, which way will the winds push the radioactive cloud?

Is there a possibility that the prevailing winds will drop this cloud on our collective doorsteps?

[avandonk]

I have read of 'incidents' where the Japanese Nuclear Industry sequentially hired homeless men to dissolve Uranium Hexafluoride in a solvent. By sequentially I mean that once they had a decent dose of radiation they were turfed out and a new lot brought in.

One bright bunch of homeless men decided that the recipe demanding mixing small amounts of solvent and Uranium salt was a waste of time. So they did a big batch all at once! Yes it went critical! Cherenkov radiation was bright enough to be seen outside the mixing room.

They all died and there was a cover up.

If this is the level of management in the Nuclear Industry in radiation aware Japan, we can never trust these Nuclear Power adherents.

Bert

[casstony]

It doesn't sound likely to get that bad, but if it does it'll be confined to the northern hemishpere initially. Not sure how long it takes to mix into the southern hemishpere.

[sjastro]

Bert,

A nice story but it seems to defy the laws of nuclear physics....

I've never heard of a uranium hexafluoride solvent that can also serve as a nuclear moderator to produce thermal neutrons that can initiate the reaction.

Regards

Steven

[GrahamL]

Mate I completely dissagree .. Its about the resilance of humanity more than you and I can ever grasp , thats so obvious in this latest terrible tragedy to drop on our meagre little planet .

The workers at the damaged plants are likely dealing with there own
life and death struggles personally , on top of having to try and roll the dice right where by even if you win, maybe you lose ( your life ).


people still searching and finding life amoungst all this carnage
its very humbling to me... possibly the barrows could be parked for a
while ...?

[Kal]

Can we please keep political discussion out of this thread. There is a time and place for politics and neither is here.

Here is a pdf that outlines the current status at the fukushima facilities:

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300273535P.pdf

Interesting to note that the spent fuel rod pools are of severe significance at the moment. The fukushima facility has around 3500 spent fuel rods in the reactor buildings (across all 6), with about 6000 more in a shared pool and 400 in dry storage. It produces around 700 spent fuel rods per year. That means that there is a significant amount of spent fuel rods in the pools in each reactor building.

I understand that reactors themselves are built with several layers of safety precautions in mind, but I do not fully understand how dangerous the spent fuel rods are. Reports were that the temperature in reactor building 4 was recorded at 84 degrees yesterday, and they suspected the storage pool was boiling. How dangerous is it to have uncooled spent fuel rods? How hot can they get? What is a worse case scenario?

[mental4astro]

I didn't make myself clear with what I ment by "money, money, money".

It is ment in the context of "quick and cheap" electrical power. Cheap for the short term which is so short sighted of the real cost.

The real cost comes in two ways: Storing the waste safely ( and there is a huge amount of it) for hunderds of thousands of years, and the massive complications that can occur when the poo hits the fan when things go wrong. How cheap is it now???

I also understand the reasons for Japan for using nuclear power, but even when the decision was first made, there were safer alternatives that never got a look in, like geothermal. The irony is that Japan propably has one of the easiest to access geothermal sources on the planet. Developing this may have taken longer, but the long term cost is really zero compared to nuclear.

I'm sorry, but for me it still is money, money, money.

It was never ment to question the bravery of those men and women who are risking their lives. If there is a God, these people are going to be looked after in the next life. I can't say the same thing about some others.

I also understand the 'political' aspect you mention Andew, but this isn't politics. Its ethics.

[casstony]

Uncovered spent fuel rods burn and emit large amounts of radiation into the air.
http://www.nytimes.com/2011/03/16/world/asia/16fuel.html

Allowable radiation doses for the workers have been increased so they can return to try to prevent this from happening.

[avandonk]

There is a fuller report in Nature and New Scientist. Once you get a couple of kg of U235 in the one place you have a problem!

bert

[gary]

Hi Kal,

The cited article from the yesterday's New York Times sums up the potential danger of
the spent fuel rod pools.

Whereas each reactor is within its own primary containment vessel, the spent fuel
rod pools sit outside of that primary vessel and on top of it, within the secondary containment building.

When you consider that the hydrogen explosions have blown the tops of
the secondary containment buildings of units 1 and 3, the spent fuel rods pools
essentially now have nothing between them and the outside world.
Unit 4 also has some holes in its roof and there has been concern as to
whether Unit 2 may blow its roof as well.

In fact if the roofs were completely blown off, it might have been somewhat easier
for the Chinook helicopter they considered using to drop water directly into the pool.
Unfortunately, judging from the photos of the very damaged buildings, at best
there appear to be various apertures in what was the roof but whether any of them
are above the pools has not been made clear in any report I have read today.

Add into the mix the risk of another hydrogen explosion occurring in any of the
units at the same time whilst the helicopter is hovering, the extent of the existing
damage which might hinder any ground crew brave enough to physically make
their way through the debris and get a hose up there, plus the risk of radiation
exposure for the crews and it really is a dire situation.

With the Washington Post reporting that the attempt yesterday to have a Chinook
drop sea water being aborted because radiation levels were too high, that in itself
is a major set back and one can only hope that the levels drop to a sufficiently
low level later today to make a second attempt possible.

But one way or the other they are going to have to get more water into those pools.

Without cooling, the spent rods get extremely hot and the fuel can melt through
the zirconium alloy tubes they are encased in. A zirconium fire can then occur,
which in the instance of these reactors, will now release radiation directly into
the atmosphere.

The Washington Post quotes Robert Alverez, from the Institute of Policy Studies,
as saying, "If the fuel pools are exposed to the air, the radiation doses coming from
them could be life-threatening up to 50 yards".

See http://www.washingtonpost.com/national/latest-nuclear-plant-explosion-in-japan-raises-radiation-fears/2011/03/15/ABwTmha_story.html

Obviously if this situation were to occur, a viscous circle could come about
whereby the radiation hazard from just one pool might then further hamper
efforts to stabilize the situation at the other units.

[DJDD]

thanks for the link, which highlights the "pros" and cons of this type of reactor.

I notice that most of the pros and cons are theoretical as there have only been pilot-scale versions, although there was already an accident in one of those in Germany, caused by a jammed pebble. So what this means, I think, is that unless we build a few hundred of these reactors we won't find out about what we did not plan for.

also, the pebble bed reactor is, i think, the type that those wishing for nuclear power to be generated in Australia are pushing to build. I remember when the nuclear debate in australia was just beginning (during the Howard years-not political comment just a timeframe) and seem to recall that the proponents of this type of reactor said that a meltdown could not occur. As I said, all based upon a couple of pilots and theory. And even if a meltdown is very unlikely to occur we have already seen that other parts of the process can lead to dire consequences. Whilst some would say these are just engineering issues that can be resolved I wonder if it is worth it and it seems we just are not good at predicting enough potential problems.

[DJDD]

I am just rereading the blog posts, etc. from some of the links that people have shared and thinking about all of the "expert" commentators (nuclear scientists, ex-nuclear scientists, ex-nuclear scientists who are pro-nuclear power in Australia) I have heard speak on the radio.

So many seem to have gotten it wrong, saying the risk of serious contamination is low or that, whilst extremely serious, the situation may have hit the peak yesterday (prior to the current discussion about the spent fuel rod pools). of course, they always seem to then end with something about not having the entire picture so there may be further complications...

Here is one I just re-read, about spent fuel rod pools and the low risk of serious accident occuring:




and, yes, I recognise the irony that I am not an expert in the field even though I am commenting upon pebble-bed reactors in a previous post...

[sjastro]

Bert,

Do you have the New Scientist reference?

I have a couple of questions.

(1) Where does the initial neutron (pre fission) source come from?

U235 emits alpha particles. The alpha particles cannot overcome the columbic barrier of U235 nuclei nor any of nuclei of the uranium hexafluoride solvents to produce pre fission neutrons.

(2) How does neutron energy moderation occur?

None of the uranium hexafluoride solvents are recognized neutron moderators. So even if it was possible to generate neutrons, if the neutrons are not thermal, radiative capture may occur where gamma radiation is emitted from the U235 nucleus instead of nuclear fission.

It seems likely the workers would have succumbed to alpha radiation rather than any nuclear reaction.

Regards

Steven

[avandonk]

See here

http://www.wise-uranium.org/eftokc.html

quote from article

"The amount of uranium contained in this tank must be strictly controlled to avoid criticality. These controls however failed, and 16 kg instead of the permitted 2.4 kg were poured into the tank. About 6 kg were already sufficient to initiate a criticality under these circumstances."

This is what happens when you have untrained people doing a highly technical job and decide to take 'obvious' shortcuts.




Bert

[CraigS]

Bert;

I see no evidence of anything other than an accident.

The officials admitted negligence and received sentences.

JCO shut the facility down and is compensating the victims.

What else could the authorities or companies do ?

Cheers

[mental4astro]

This is a truely facinating thread. I'm learning so much. Ta.

[CraigS]

Bring on fusion ..
:)

[avandonk]

Their negligence was hiring homeless men to do the dirty work without safeguards or supervision. How else do you explain 16kg in the tank when 2.4kg was the absolute maximum to avoid criticality.

The whole sorry saga was written up in Nature and New Scientist with all the details of mismanagement.

I doubt if you would even sit next to 16kg of 18% U235 even when it had not undergone criticality. The natural decay rate of U235 is quite high and can be calculated for 18% x 16kg which is nealy 3kg of pure U235!

This is a dry technical report of negligence bordering on stupidity not an accident.

Bert

[RickS]

I don't think it has been mentioned here already... there is an interesting ongoing commentary at the MIT NSE Nuclear Information Hub: http://mitnse.com

[DJDD]

that is where I took my quote about the low risk of the spent fuel rod pools becoming a danger...

the discussion is interesting but anything beyond pure information, e.g. what are spent fuel rods, and into risks and outcomes seems to be speculation.

[avandonk]

As a final note if a homeless alcoholic man was seen vomiting and bleeding from all his orifices the immediate conclusion would be that it was self inflicted not due to massive doses of radiation.

This is called a sound management policy.

I am sure far more sound management decisions to save money have been made to produce the current situation. This is what happens when bean counters attempt to make what should be technical decisions.

Bert

[FredSnerd]

The dinosaurs had big bodies and little brains and walked the earth for 160 million years. Humans have comparatively little bodies and huge brains and have walked the earth for what; maybe 1.5 million years. Does anyone really think we’ll make it to 2 million years? Not likely is it? But of course when we go we want to make sure that every other living organism on earth goes with us. At the moment there’s almost 500 nuclear reactors on earth and every one of them is like having a wolf by the throat. You can’t leave them unattended because if you do they’ll all meltdown and spray radioactive poison in the atmosphere that will linger for thousands of years. If and when a more encompassing crisis hits will people continue to maintain all those reactors. This is time bomb stuff.


It’s interesting to see that a few have posted the link to the article from BraveNewClimate (the voices of reason amongst us). But of course BraveNewClimate is a site specifically dedicated to the promotion of nuclear power around the world (which doesn’t seem to have mattered to the voices of reason). And what’s really interesting is how some of the more emphatic statements in that article have been removed or toned down since it was first posted a few days ago. Because of course many of the things they said a few days ago couldn’t possibly happen are happening today, including their claim that this could never develop into a Chernobyl. Well, so much for that. And of course if a crisis like Chernobyl is averted, its no thanks to the nuclear power industry but to the 50 workers who will probably lose their lives to save the thousands in Japan and beyond who might otherwise be effected.



500 nuclear reactors on earth and counting, which means the probability of this happening again is ever increasing. And of course the more regularly this happens the more we become acclimatised and accept it. Which reminds me of something else that seems to have been removed from the BraveNewClimate article. The suggestion in the earlier versions that although a meltdown should be avoided, if it happens it’s not really that disastrous.

[gary]

Story here -
http://www.smh.com.au/environment/helicopter-dumps-water-on-reactor-amid-claim-of--extremely-high-radiation-20110317-1bxm8.html

NHK report operations will be limited to 40 minutes per helicopter per day because of
the radiation hazard.

NHK report attempts will be made this afternoon to restore the power supply to the reactors facility.
Since the original pumps have been damaged, a spokesman reports they will attempt to install a temporary cooling
system.

[sjastro]

Thanks for the info Bert.

With regards to where the initial neutrons came from, I should have realized that heavy elements such as U235 can undergoe spontaneous or natural fission which provides the neutrons to initiate the chain reaction.

Ironically and tragically the water cooling jacket used at the Tokai plant acted as a neutron moderator resulting in thermal neutrons which initiated an accidental nuclear fission.

Regards

Steven

[DavidU]

The spent fuel rods are exposed and they are dumping water on the building via helicopters. These pilots should get medals !

[DJDD]

hear hear!




I am sure there will lots of backfilling on this topic.
but no-one will remember or care except a committed few...

[DJDD]

I just read this article on the age's website:
http://www.theage.com.au/world/heroic-50-sent-in-to-save-millions-20110316-1bxgw.html


should any of these workers die or become seriously ill I hope their families will be well compensated for life...

[gary]

Today's New York Times highlights the troubles besetting Reactor No. 4.

Gregory Jaczko, the chairman of the United States Nuclear Regulatory Commission,
has testified to Congress that commission representatives in Tokyo have
confirmed that the Reactor 4 spent rod cooling pool is empty of water.



Whereas some attempt was made yesterday (Thursday) to drop sea water from
the Chinook helicopters onto Reactor 3, the New York Times reports -



Meanwhile, it is reported workers are attempting to restore power to the crippled
plant.

Story here -
http://www.nytimes.com/2011/03/18/world/asia/18nuclear.html?pagewanted=1&hp


In the coming days, should the helicopters stop dropping water but instead switch
to dropping material such as sand or foam, it may be an indication that the spent
fuel rod pool is completely dry and that the rods have heated to around 1800C
and melted through their zirconium cladding and that a "zirconium cladding
fire" is underway. Hopefully this scenario will not arise, but if it should,
dousing the burning rods with water is the incorrect approach as the steam
carries away with it highly irradiated aerosols.

Hopefully Reactor 4's spent rod pool can be filled with water before the rods begin
to melt.

During the Chernobyl event, Soviet Mi-8 helicopter pilots dropped some 16.7 million
kg of sand on the stricken reactor in the first two months.

[casstony]

I'm thinking the pilots/workers should get a few million dollars deposited into their families accounts before this is over - medals won't do their families much good in a few years.

[avandonk]

Fusion reactors need exotic metals for the plasma containment toroid. The neutron flux is very high and eventually weakens the structure of the toroid metals. These metals become highly radioactive as well by the production of isotopes by the neutrons. Even with a life time of twenty years of the reactor it would be too dangerouss to dismantle. It would have to be entombed and a new one built next door.

The only safe reactor is the one in the sky. I predict it will be used when the psychopathic corporations figure out a way to get ownership by theft.

Bert

[sjastro]

It's why He-3 is a nucleus "of interest". Fusion of He-3 does not produce neutrons but protons which can be contained in an electric or magnetic field.

Regards

Steven

[avandonk]

We have reached 'peak' helium. Where do we get He-3?

Bert

[michaellxv]

Isn't there vast stores of it on the moon?

[sjastro]

Lunar rock samples indicate that He-3 is much more abundant on the moon.

It's no coincidence that the re-exploration of the moon is based on commercial interests. The Chinese and Russians have indicated that the objective of further lunar exploration is for the mining of He-3.

Regards

Steven

[avandonk]

Tell 'em they are dreamin'!

Bert

[sjastro]

Why Bert?

[CraigS]

Bert;

Are you asking for someone to answer all the current research issues presently under consideration ?

Solar has its research problems, also … the biggest being that it can't deliver anywhere near the power/performance levels required to meet current day demands !

Try Aneutronic Fusion research !

Cheers

[avandonk]

With current technology the cost would be far more than the benefits. Even with rail launch technology to get materials back to Earth 'cheaply' the problems of mining and purifying would be horrendous. It is the stuff of science fiction. Robotic miners and plants I doubt it.

We cannot even control 1950's nuclear technology because of cost cutting. The current situation is a grim picture of the realities.

When I was a kid I saw a picture of a very long train with coal and it was the equivalent of one pound of U235. We have not got that correct yet.
ALL current nuclear reactors would not exist without taxpayer or weapons manufacture subsidies!

Bert

[avandonk]

I used to be in charge of three million dollars of the best available equipment in a protein structure xray lab. Not a day went by without human intervention to prevent failures or outright disasters. I rest my case.

Bert

[multiweb]

Good to see some light (http://www.cbc.ca/news/technology/quirks-quarks-blog/2011/03/japans-nuclear-success.html)at the end of the tunnel. Kudos to them in handling a task that is just hard to comprehend on such a massive scale.

[Kal]

I think the best news that I have seen over the last 24 hours is that there is no more major bad news.

The incident has been raised to a level 5 by the Nuclear and Industrial Safety Agency after after engineers reviewed images showing damage to fuel rods and other structures inside the reactor buildings.

source (http://edition.cnn.com/2011/WORLD/asiapcf/03/18/japan.nuclear.reactors/index.html?hpt=C2)

[gary]

Both the Washington Post and New York Times are reporting that prior to the
disaster, Unit 4's fresh fuel core of 548 rods had been off-loaded into the spent
fuel pool. There are a total of 1,149 rods in the pool.

Graphic here in Washington Post -
http://www.washingtonpost.com/wp-srv/special/world/japan-nuclear-reactors-and-seismic-activity/?hpid=z3

Of serious concern is that both papers report that the NRC believes there is no
water left in Unit 4's spent rod pool and that, as the Washington Post reports -
"TEPCO reports that part of the pool's reinforced concrete wall has fallen away,
leaving just a thin stainless-steel liner."

Whilst workers were scrambling to restore power to the plants, those following
these events closely will be aware that most of the effort using water cannons
had gone into Unit 3. Attempts to fill the spent water pool on Unit 4
had been "postponed". At least part of the reason for this was concern
over Unit 3's use of MOX fuel - a uranium/plutonium blend.

Left uncooled, the spent fool rods continue to heat under normal fission decay
and their temperature rises. Over time, once the rods reach a temperature
of around 1800C to 2200C the fuel will melt through the zirconium alloy cladding
and a "zirconium cladding fire" can occur. Such an event results in the airborne
release of radiation.

The information that half of Unit 4's spent reactor pool consists of fresh fuel rods
is of serious concern. When rods are fresh, their concentration levels of the
radioactive isotope Iodine-131 is much higher than when they are depleted.
Iodine-131 has a very short half-life of about eight days. But its intense mode of beta
and gamma decay is such that it poses a significant contribution to the total
health risk from a nuclear accident or nuclear bomb explosion.

The thyroid gland, which is in the neck below the larynx, takes up iodine from the
blood stream and uses it to make thyroid hormone. Unfortunately, the gland
is unable to discriminate between stable and radioactive forms of iodine.
For this reason, Potassium iodide tablets are prescribed to be taken up to
two days before potential radiation exposure. Their job is to flood the thyroid with
stable iodine so it will not take up the harmful Iodine-131. It is these tablets that
were being administered to those Japanese who could potentially be exposed to
harmful levels of radiation, such as those that were living in the exclusion zones.

During the Chernobyl event, unfortunately there was no prior warning of the
radiation release.

The events of the past week gave me reason to re-read Pulitzer Prize winning
author Richard Rhodes' account of the Chernobyl event in the opening chapter
of his book on the arms race, "Arsenals of Folly".



As Rhodes wrote,


By contrast, the Japanese population as a whole has one of the highest iodine
consumption intakes in the world, including sources such as seaweed.

In any case, we are all anxiously hoping that those workers who are desperately
trying to stabilize the situation with the Fukushima plant will succeed. However,
they are by no means out of the woods and industry observers quoted by papers
such as the New York Times suggest that this phase of operations still has a
couple of more weeks to play out.

The fact that Reactor 4's spent fuel pool also has fresh rods in it and that the
pool is said to be dry and the concrete damaged, is of a major concern.

[CraigS]

Gary;
I guess the more rods in a pool, the quicker it heats up too ...



This suggests resourcing limitations .. surely resourcing shouldn't be a problem in a situation like this ? Everybody seems willing to assist .. so I wonder why they have really chosen to postpone dousing Unit 4 as well ?

I'm finding this one hard to fathom ..

[gary]

Hi Craig,

Thanks for the response.

The rods that are fresh will emit more energy per minute than those that have been
"used". Thus adding fresh rods into the pool will heat it more rapidly than adding
the equivalent number of used rods.

Most of the heat comes from natural decay. When the rods are stacked in the pool
they will be sub-critical.

However, if the rods are left without water and reach a temperature where they
melt through their cladding, two bad scenarios can arise. One is a cladding
fire where harmful radiation can be emitted as aerosols. The second is the
risk that the rods, rather than being stacked with separations between each other
as they are now, mechanically collapse toward each other or form a molten
mass on the bottom of the pond that then becomes critical. Massive amounts of
radiation would be emitted. Keep in mind that these rods are outside the primary
containment and that the secondary containment is severely compromised.



As has been widely reported, there has been much criticism about the amount
of clear information coming out of TEPCO. Whilst working here over the past week,
my work environment allowed me to leave NHK Live TV on in the background
a good deal of the time. Whilst listening to those live broadcasts which include
regular reports from Japanese government agencies and TEPCO and combined
with what I have been reading regularly in sources such as the New York Times, etc.,
I have personally not heard an explanation as to why little had or could be
done at Unit 4 except for the concerns of the MOX fuel in Unit 3 and what
was quoted as "high levels of radiation" at Unit 4.

Thus one can only speculate as to some possibilities. It could be that physically there
were debris leading up to the access point of Unit 4 that was hampering workers
from getting close to it. It could be that the uncovered pool of Unit 4 was resulting
in radiation levels too dangerously high for workers to get to. Or it could be that
they felt Unit 3 was more of concern. I just don't know.

With regards the "resourcing limitation" question you raise, rather than address
it directly myself, I commend to you a commentary piece that appeared in yesterday's
Washington Post which starts with the leading opening -



That story is here -
http://www.washingtonpost.com/national/nuclear-crisis-solutions-simple-but-not-easy/2011/03/17/ABK6E7m_story.html

Certainly the revelation that half of Unit 4's spent fuel pool consists of fresh rods
is one of the worse pieces of news to come out of Fukushima in the past week.

[CraigS]

I understand that the Fukushima Daiichi reactors were 40 years old, and are based on a design from the sixties.

I read somewhere (in all of these links) that one of them was due for decommissioning, which might explain why there were fresh rods in the pool. (?)

I understand there are much newer designs which incorporate newer safety features. Mind you, I suspect they'll be changes to those designs, in the light of this mess.

Rgds.

[Sylvain]

Once again a situation where saving money comes before safety precautions:

- Plant built to resit to up to magnitude 7 quakes in a country that is probably the most exposed to massive quakes - saving money on construction

- Safety diesel engines implemented in a zone subjected to water flooding (considering the risk of tsunamis with the plant being on the coast it's mad) - saving more money on construction

- Tepco did not immediately decided on flooding the reactors with sea water, probably in an attempt to save them. They eventually did but wasted precious time.

So now, thousands of people's lives are at risk.
Great.

[CraigS]

Just found a reputable site … the IAEA (International Atomic Energy Agency) (http://www.iaea.org/About/)



This is the guy who flew into Tokyo a couple of days ago and has been talking with the TEPC Vice President and the Japanese PM.

and they say ..
Japan Earthquake Update (19 March 2011, 4:30 UTC) (http://www.iaea.org/newscenter/news/tsunamiupdate01.html)


The give a daily site-by-site status update on the developing situation.

… A reputable site for updates, I would think …

Cheers

[Sylvain]

I recommend following the BBC live coverage of the events unfolding in Japan. Very informative and updates come on in all the time.
Focus on the updates on the left hand side of the page.
The videos on the right are good too, but the same videos are being played over and over again.

http://www.bbc.co.uk/news/world-middle-east-12307698

Cheers

[gary]

Hi Craig,

Thanks for the link to the IAEA Fukushima status page.

The confirmation that, for Unit 4, "All fuel had been removed from the reactor core for
routine maintenance before the earthquake and placed into the spent fuel pool",
and that "a portion of the building's outer shell was damaged" is consistent with the US
NRC reporting and a set of facts of considerable concern.

That unit had a output capacity of 1100 MW of power. The source of that power
was purely from its fuel rods when in a controlled fission state. Now those fuel
rods, the potential source of all that energy, are inconveniently sitting outside
the primary containment vessel effectively out in the open. Separated by space gaps,
they currently do not form a critical assembly, but they are rising in temperature
hour by hour. If they should catch fire and melt (and they eventually will if they cannot be cooled),
they may form a conglomerated mass and a fission reaction will begin again releasing
even more energy. So there is a real race against time here probably over the next few weeks.

The pool structures are said to be made of concrete lined with "a thin
stainless steel liner". One concern from TEPCO has been that the concrete on
Unit 4's pool has partially fallen away leaving only the stainless steel liner.

It would be interesting to learn of a link to an authoritative source as to whether it is
believed the thin stainless steel liner of the cooling pool will be sufficient or not
to hold the rods in the spent pool, should the worse occur and the rods melt.

One can only hope that Unit 4's pool is watertight and that, if it is not too late,
water can be added to it. Should a cladding fire occur, water is not the
correct material to pour on it. In that eventuality, they may have to start dropping
large amounts of sand on it, possibly mixed with boron, which acts as a neutron
poison. Hopefully this will not occur, but suffice to say, it would be an act of
desperation.

Yesterday, France flew out 95 tonnes of boron destined for Japan.
See http://www.straitstimes.com/BreakingNews/World/Story/STIStory_646202.html

[Sylvain]

Some things are just ridiculous:

"Mr Besson said that France had offered the boron on Saturday, the day after Japan's biggest earthquake on record struck but 'either they didn't think it was useful or they didn't have the time to reply.'"


"0409: The Yomiuri Shimbun claims the Japanese government did turn down a US offer of technical help to cool the overheating nuclear reactors, soon after the earthquake. The paper, citing an anonymous senior member of the Democratic Party, said the offer was refused because it was felt to be "premature". Last week Tokyo denied turning down an American offer of help."

-_-'

[CraigS]

Gary;

I wonder the melting point of the Stainless Steel would be relative to the rod encasement ?

I think type 304 stainless has a melting point of around 1400 - 1450 degrees C.

I'm sure the composition of the tank would have been carefully selected for other properties, as well, though.

I suppose it doesn't really matter if the rod encasement decides to light up !

[CraigS]

Sylvain;

There are heaps of reasons this may have occurred.
Eg: Perhaps they didn't know the exact status of anything at that stage. (I mean, a tsunami had just hit following massive damage everywhere)..

If someone asks do you need help immediately after a catastrophe, more often than not, its difficult to answer definitively. Straight after the offer, the next question is likely to be .. 'what kind of help do you need ?'

How do you answer that if you don't know exactly what's happening ?

Its easy to have opinions after the fact .. but consider what these people have just gone through … and, they've been running these reactors for forty years !

They have the expertise and nuclear resources !

[Sylvain]

I guess all I am trying to say is that no chances should have been taken. It's better to have too much help than not enough.

I am not making any judgement, in fact I don't think other countries would be any better at handling the situation.
I just hope they somehow manage to cool the reactors down, but it's looking too optimistic at this stage. :(

[Sylvain]

Apologies if I am sounding a bit harsh, but it's just that I have loved ones in the vicinity and I'm worried.

[multiweb]

I think this statement is spot on. We're all looking from a distance in the comfort of our living room watching TV and saying what were/are they thinking. But the fact is that those guys have been hit repeatidly by a series of unprecedented events. There is a massive psychological effect to the whole story too. They have to cope with it all on ground zero. It's so overwhelming they probably don't know where to start. I'd say give them a break. They're doing a grand job so far.

[CraigS]

Here's a photo of a fuel storage pool. The caption reads:



(from NY Times).

[gary]

Hi Craig,

Thanks for the photo. Alas the pool is outside the primary containment area
and only in the secondary area, which is the outer building which has been damaged.
This New York Times short video shows their location graphically -
http://www.nytimes.com/2011/03/19/world/asia/19japan.html?hp

New York Times also has this excellent interactive step-by-step graphic showing
more detail of the pools under the heading "Hazards of Storing Spent Fuel"
http://www.nytimes.com/interactive/2011/03/12/world/asia/the-explosion-at-the-japanese-reactor.html?ref=asia

Here is a link to a PDF of a PowerPoint presentation dated 16 Nov 2010
by Yumiko Kumano of the Tokyo Electric Power Company entitled
"Integrity Inspection of Dry Storage Casks and Spent Fuels at Fukushima Daiichi
Nuclear Power Station".
http://www.nirs.org/reactorwatch/accidents/6-1_powerpoint.pdf

[CraigS]

Thanks Gary;

Excellent interactive and info ... makes it all look pristine, shiny and new .. pity the one that matters looks nothing like this !

Rgds

[gary]

According to today's New York Times, unfortunately the Japanese Government
has detected "abnormal levels" of radiation in spinach and milk in Fukushima and
Ibaraki prefectures.





Story here -
http://www.nytimes.com/2011/03/20/world/asia/20japan.html?hp

[CraigS]

Oh brother .. those words … 'please say calm' !
:sadeyes:
Mind you, the levels could've been at those levels before the accident too, maybe ?

[Sylvain]

"0907: Despite encouraging reports about progressing reconnecting power to cooling systems at the Fukushima plant, the BBC's Tim Willcox cautions that they are still nowhere near the process of restarting the pumps as it is unclear whether - given quake and tsunami damage - they even still work. Even if they do initially work, they could quickly short out."

(From the BBC news update link I gave before).
It would be good if the Japanese government would let us know what the hell is going on down there.

[Sylvain]

Some hope:

"1200: Power lines have been connected to the Fukushima nuclear plant's reactor 2 but electricity has not been restored yet, a spokesman for Japan's nuclear safety agency has said according to AFP. "If the power is turned on without checks it may malfunction. They are checking the facility now. If no problem is found at the facility today, the power will resume as early as tomorrow [Sunday].""

Fingers crossed.

[Sylvain]

Another update from the IAEA:

"1543: The IAEA is giving a press conference on the situation at the Fukushima Daiichi nuclear power plant. It hopes that power will be restored to reactor 2 today, which will then act as a hub to restore power to reactor 1. However it is not clear if water pumps have been damaged and if they will even work once power has been restored."

[CraigS]

So, from this morning's news, looks like Nos 5 and 6 are being cooled by two emergency diesels. As per Sylvain's posts, power lines have been run into No 2, but they have not yet succeeded in reconnecting power (just yet - a few minor problems by the sound of it - they had to run the lines in darkness). Once they get power to No 2 it will act as a hub for No 1 as well.

Nos 3 and 4 would then seem to be the biggest problems. From the Washington Post:



It seems as though they don't have reliable info on the water and temperature levels at Nos 3 or 4.

From the SMH:


Radiation levels (from IAEA):


I wouldn't be drinking milk for a while. Spinach is also off the menu.

Rgds

[Sylvain]

Thanks for the update Craig.
I read that traces of radioactive iodine where detected into tap water in Tokyo and other cities. They say it is not harmful to human health but also said there is normally no traces whatsoever.

Reactors 3 & 4 definitely remain the main concern. Let's hope they get the cooling pumps to work again.

[gary]

Hi Craig, Hi Sylvain,

Thank you both very much for the synopsis of the situation as it stands this Sunday
morning.

A picture appears in the Sydney Morning Herald today of what the caption says to be
the green crane for the spent rod pool for No. 4. It can be seen through a gaping hole
in the side of the damaged secondary containment building.
See http://www.smh.com.au/environment/power-restored-at-one-of-plants-reactors-20110319-1c1cu.html

The caption also reads the storage pond is just out of sight in the shot and that it
has "boiled dry".

One would hope that the hole in the side of the wall allows them the opportunity to
get a remote camera in there by one way or another.

It is clear that an important piece of information will be the status of the mechanical
integrity of the pool itself.

If it can still hold water, it will undoubtedly give them one option which they will
be deliberating over, which is whether to try and get water back into it. Depending
upon the integrity of the rods, half of which are "fresh", they may be weighing up
whether the risks, both short and long term, of the initial steam cloud of radiation
that will be emitted is less than those from taking some other action, such as
attempting to entomb it, first with sand and boron and later with concrete.

The lack of time, the prevailing winds, the fact that it is probably easier to fire
water through the hole in the wall than try to get sand in there, the risk of a meltdown,
etc. must all be featuring as bullet points on white boards up there.

But if Unit 4's pool can't hold water, or if it is deemed too much of a radiation
risk to douse them now, then the alternative remedies would create new
challenges.

At present, the fact that No. 4's roof, though damaged, still provides some
covering may help prevent steam and radioactivity from rising higher into the air
if they should douse the pool. If the prevailing winds allowed the steam to go offshore
out into the Pacific, it may help curtail more damaging contamination on the
Japanese mainland. However, that same roof covering would not make it easy to
try and get material such as sand dropped in from the top in which case they
might have to convey it through the hole in the side.

[gary]

NHK reporting that Self-Defense Forces, under orders of the Japanese Government, are now spraying water into No. 4.
Unmanned water spraying vehicle is being deployed.

Story and video -
http://www3.nhk.or.jp/daily/english/20_10.html



Meantime, a 13 hour water spaying operation at No. 3 has ended.

[Sylvain]

Thanks for the update Gary, much appreciated.
If anyone has a link with the latest winds I'm keen on having a look, I haven't been able to find anything.

[xelasnave]

I doubt if we will see NP being set aside but dangerous things like incandescent light globes are being dealt with;) as is smoking:P or exceeding the speed limit by 5 klms:rolleyes:.... so given these facts NP must be safer than smoking:eyepop: however we need to learn or understand that the demands for energy will not go away or be solved ...human population has trebled in my lifetime and I expect population to grow beyond our wildest dreams (or nightmares)...AND so I suspect the demand for energy will always be ahead of supply as thats the way it is for humans:)....so in an effort to make NP safe I suggest that all future plants be constructed at the bottom of lakes:eyepop:... sounds off beat however such an approach would see the entire plant cooled when their roof gets blown off in an unexpected accident:rolleyes:... imagine say the plant we are concerned with was constructed under 100 feet of water ..cooling would not be a problem.

Also given the hydrogen that was manufactured should we not be looking at producing H at NP plants and powering H cars???

Thanks to those who have worked upon this thread .
It is wonderful to be able to get such a great overview from folk who we know are reliable.

alex:):):)

[gary]

Hi Sylvain,

If you go to this web page -
http://www3.nhk.or.jp/nhkworld/
you can watch NHK Live TV in English.

Now and then they have weather reports and I am watching now for an update.

Also looking here at Japan Bureau of Meteorology site -
http://www.jma.go.jp/en/amedas/205.html?elementCode=1 (Fukushima)
http://www.jma.go.jp/en/amedas/206.html?elementCode=1 (Tokyo)
http://www.jma.go.jp/en/amedas/000.html?elementCode=1 (All of Japan)

At a glance, unfortunately the winds look like they are currently blowing west and south-west.
In any case, the winds appear to be light.

[CraigS]

Interestingly, I was looking at radiation levels and the effect on the human body .. (a little maudlin) but I noticed that smoking 1.5 packs a day results in 13-60 mSv/year.
The current avg limit for nuclear workers is 20 mSv/year !
So yes, from a radiation dosage perspective, smoking 1.5 packs/day may be more dangerous than working at an N. plant !



I'd love to see you take some sort of engineering training, Alex.

Perhaps then you might benefit from an appreciation of the constraints imposed by the real world, upon unbridled thinking.
:) :)

[CraigS]

In the tons of reading material on this topic floating around, I found a very interesting journo article which outlines differences between the Fuskishima situation and Chernobyl.

Article here (http://www.propublica.org/article/six-ways-fukushima-is-not-chernobyl) .. (apologies if you've already read it).

The main points are as follows:

1. Chernobyl's reactor had no containment structure.

2. Chernobyl's reactors had several design flaws that made the crisis harder to control. Most crucially, their cooling system had a "positive void coefficient," which means that as coolant water is lost or turns into steam, the reaction speeds up and becomes more intense, creating a vicious feedback loop.

3. The carbon in Chernobyl's reactor fueled a fire that spewed radioactive material further into the atmosphere. Fukushima's reactors do not contain carbon, which means that the contamination from an explosion would remain more localized.

4. Unlike Chernobyl, however, a meltdown at Daiichi could end up contaminating the water table.

5. Much of the public health impact of Chernobyl was the result of the Soviet government's attempt to cover up the crisis, rather than moving quickly to inform and protect the public.

6. Emergency workers at Chernobyl took few precautions, and may not have been fully informed about the risks they were taking.

Interesting comparison .. but maybe premature. We don't know enough about what actions have been taken, and under what circumstances, at Fukushima.

[gary]

Hi Craig,

Thanks to the link to the article.

In Richard Rhodes (http://en.wikipedia.org/wiki/Richard_Rhodes)' 2007 book, "Arsenals of Folly (http:http://www.amazon.com/Arsenals-Folly-Making-Nuclear-Arms/dp/0375414134//)", on page 5 he talks about the
2,000,000 pound concrete lid atop the Chernobyl reactor which acted as a
biological shield.

The men who operated this class of reactor jokingly referred to the lid as the
pyatachok, which is a very small five-kopek piece Russian coin.

When the accident began, water flashed to superheated steam and an eyewitness
later reported that the pyatachok "began to bubble and dance".

There were then two explosions lasting four seconds and they lifted the two
million pound pyatachok up and tilted it almost vertically.

The reactor core blew tons of redhot radioactive debris "past the pyatachok,
through the roof, and half a mile into the air".

Parts of the red hot material then landed on the roofs of the reactor complex.
Rhodes writes, "To lower construction costs, the roofs had been covered with
flammable asphalt; the hot graphite set them on fire."

in the days and months that followed, a squadron of big Soviet Mi-8 helicopters
was deployed to drop sand onto the reactor.

Rhodes writes, "Pilots protected themselves by stuffing lead plates under their seats.
They coined a slogan to suit the circumstances: "If you want to be a dad,
cover your b*lls with lead".

"Each crew member received 20 to 80 rads of radiation on each flight".
Many were sent to Kiev for radiation treatment and the number who died or
were disabled was never revealed.

The fallout reached Kiev. Rhodes reports that when the chestnut trees dropped
their autumn leaves, they raked up three hundred thousand tons of them and
buried them "outside the city as low-level nuclear waste".

One worker reported "We buried the forest". "We sawed the trees into meter-and-a-half
pieces and packed them in cellophane and threw them into graves".

Eventually Reactor 4 at Chernobyl was entombed into a sarcophagus of "half a million
cubic tons of reinforced concrete".

[Sylvain]

Crazy hey.
Thanks Gary for the Wind map, very useful.
Would you - or someone else - have another link for the live coverage (twitter-like) of the situation?
The BBC link I gave before has not been updated today, I don't know if it is because they are having technical difficulties or because they are covering the situation in Lybia.

If anyone had a good link that provide live info, it'd be great.
thanks.
Sylvain

[ballaratdragons]

Another 6.1 has just happened right on the coast just north of Sendai.

[gary]

NHK reports that the dousing of No 4 pool concluded before 8PM Japan Standard Time,
having sprayed 100 tons of water, much of which they report reaching inside the
reactor building.

Story here -
http://www3.nhk.or.jp/daily/english/20_31.html

[Steffen]

Yes, perspective is a useful thing. I found this interesting, too: http://xkcd.com/radiation/

Cheers
Steffen.

[ballaratdragons]

Wow!

Eating 1 banana gives you more radiation than living within 50 miles of a Nuclear Plant for a Year!

And even more amazing is that there is 3 times more radiation living within 50 miles of a Coal power station than living within 50 miles of a Nuclear Power station

:eyepop:

[wavelandscott]

Not that amazing at all..."relative risk" is an important concept that often gets overlooked. Consider the relative toxicity of many household items...salt aspirin etc. A little perspective goes a long way.

[Sylvain]

That being said I wouldn't be comfortable drinking contaminated water and eating contaminated veggies. The government can say that the levels are "perfectly safe", I also recall governments saying the Chernobyl cloud stopped at the frontier. Given the poor communication that has been going on, I would certainly not trust that government. The matter here is not whether small amounts of radioactivity are dangerous for human health or not, but rather what are people truly exposed to and of course is the damn thing going to explode?

[xelasnave]

Hi Craig.... engineers are there to make the impossible possible.

Give an engineer a difficult problem and he is happy to hunt down a solution. Never had to use one myself but I accept the importance of their role in making things happen.

We already have neuclear reactors under water:eyepop: in the form of "atomic submarines" and I expect that building a building under water is not that hard really.... access by tunnel (like the one under Sydney Harbour) in fact I can imagine in the public area we could have an aquarium which is really the lake around the plant.

As I said it sounds off beat but the more you think about the benifits the more I think the idea may be the only one that will save the NP industry... Someone else will have to take it further as I have many other ideas that I am working on not related to saving the planet;).


alex:):):)

[gary]

Japan's national broadcaster, NHK, report -



Story, video here -
http://www3.nhk.or.jp/daily/english/21_14.html

NHK TV are reporting for those in the exclusion zone, if caught in the rain, they should
then go shower to remove any contamination from the skin.

NHK also report temperatures in pools all below 100C. Normally pool
temperatures are in the 30C range and measurements in various pools today are
in the 40C to 60C range which is slightly higher than normal, but good news.
Story on water temperatures here -
http://www3.nhk.or.jp/daily/english/20_33.html

Meantime TEPCO are attempting to stabilize the pressure within overheating Reactor 3
but have decided against releasing gases from it.


Story on No 3, here -
http://www3.nhk.or.jp/daily/english/20_23.html

NHK TV report that Reactor buildings 1 and 2 are intact but attempts to restore power to No. 2 have been
delayed as some equipment such as monitoring meters were shorted and will need to be replaced. This work
is expected to take three to four days.

[Sylvain]

Thanks for the update Gary.
It's not looking very good...they are making very little progress and it's been almost 10days now :/

[gary]

The New York Times has another interactive graphic and related article entitled
"Deconstructing a Controversial Design".



The graphics and article attempts to explain the series of design decisions that went
into the Mark 1 Boiling Water Reactor that lead to the spent fuel rod pools being positioned at the top.

Step by step interactive graphic -
http://www.nytimes.com/2011/03/21/business/global/21sony.html?_r=1&ref=business
Related article -
http://www.nytimes.com/2011/03/20/weekinreview/20wald.html

Track the reactor status here -
http://www.nytimes.com/interactive/2011/03/16/world/asia/reactors-status.html

[CraigS]

More not-so-good news:

Radioactive substances in seawater near Japan nuke plant (http://www.physorg.com/news/2011-03-radioactive-substances-seawater-japan-nuke.html)



Its probably authentic information, given the quantitative nature of the information.

I think swimming might be off the activities list this Summer.

I'd be dodging sea-food as well. Unfortunately those who live there don't have this luxury !

[Sylvain]

Gary,

Thanks for the great links! Especially the reactor status is very useful and informative.

Craig, thanks for the update too, I missed this bit of information. It wouldn't be surprising, but it's very sad :(
I think at this stage the greatest concern is about reactor 3 & 4. And having to evacuate crews does not help in resolving the situation unfortunately.

Thanks for the updates and info guys.

[gary]

Thanks Sylvain,

This Reuters link may also be of interest to you.
http://live.reuters.com/Event/Japan_earthquake2?ShowComments=0

It provides "live updates of developments after the earthquake and tsunami" including
news on the Fukushima plant, "selected by Reuters.com editors and readers.
To see updates from Reuters only, click Options and turn off comments".

The page updates automatically.

[gary]

Hi Craig,

Thanks for the link to the story.

When I read the same syndicated AFP story in this morning's Sydney Morning
Herald (http://www.smh.com.au/environment/radioactive-substances-in-seawater-near-japan-nuclear-plant-20110322-1c43t.html), the numbers reported at that distance at sea were so high compared to
equivalent reported readings at similar distances on the land, that it gave me
reason to wonder if the AFP story had made an error.

Googling about, as best as I can ascertain so far, many news outlets sourced a
story from the Kyodo News Agency in Japan.
See http://english.kyodonews.jp/news/2011/03/80024.html



So perhaps the 100km is a typo error made by a journalist somewhere in the chain
and perhaps it was meant to be, say, 100m?

The best source might be the original TEPCO briefing itself which was probably
broadcast on NHK TV this morning but I have not had the opportunity to watch yet.

When watching the broadcasts over the past week or so, it has often given
me reason to pause to ponder the skill of professional translators who can listen
to a conversation, translate and speak themselves in real time. But in this instance,
another possibility is perhaps something may have got Lost In Translation somewhere?

I am confident one of us will be able to find the original source soon to verify the
numbers.

Nevertheless, irrespective of the distance from the plant, for a nation that can readily
consume fish for breakfast, sushi for lunch and sea slug for dinner, any radioactive
poisoning of the food chain in the surrounding waters is bad news.

As we witnessed on television, many of the worse affected areas in the tsunami
were fishing villages.

Postscript:

Found this -

Press Release on TEPCO web site here -
http://www.tepco.co.jp/en/press/corp-com/release/11032201-e.html



Here is a link to a PDF of the TEPCO analysis -
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110322e1.pdf
Dated 14:39 March 21st 2011 it shows the place as "southern discharge canal (about 100 meters south
from 1_4u discharge canal)."

[wavelandscott]

From Gary: " When watching the broadcasts over the past week or so, it has often given me reason to pause to ponder the skill of professional translators who can listen to a conversation, translate and speak themselves in real time. But in this instance, another possibility is perhaps something may have got Lost In Translation somewhere?"


This is normal and Japanese is hard to translate...their language is very indirect and I notice my colleagues often struggle with terms that represent degrees of something...may, could, should, must...and related

[CraigS]

Gary;
Thanks for the 'heads-up' on the 100m vs 100km. I look at all this news with some degree of skepticism.

It may only be 100 m, but 'iodine at levels 126.7 times higher than the legal concentration limit and radioactive cesium 24.8 times higher', is the real worry.

And, it seems there were 'no radioactive substances recently detected in seawater before the disaster', also.

I presume the iodine problem will be short-lived, but the Caesium contamination, isn't good.

Hi Scott;
I see your point about the translation side of things, also. Thanks for your input … 'tis always good to have input from someone who may have to deal with it on a day-to-day basis.
Thanks kindly,
Craig.

[casstony]

Article in the Telegraph about China pursuing thorium based reactors; apparently much safer than current reactors but not pursued by the major powers since you can't make plutonium for bombs: http://www.telegraph.co.uk/finance/comment/ambroseevans_pritchard/8393984/Safe-nuclear-does-exist-and-China-is-leading-the-way-with-thorium.html

[xelasnave]

I have often wondered why not thorium... there is material suggesting it is the go but I felt there must have been something holding it back... now its clear ..no military application... there is plenty of thorium available so why not.
It could be the answer.

alex:):):)

[xelasnave]

With the spinach and bok choi getting radiation I wondered this today.... say the farmers gathered up their contaminated harvests and sort to compost them (compost is the practice of heaping your vegetable wastes and letting them break down via biological/bacterial action so as to produce a nutriment rich material called compost..it can be used as one would use fertilizer... I ask would the compost heap go critical if large enough?... I have a feeling it could:shrug:...any thoughts?

alex:):):)

[gary]

Free to air TV station 7mate have a one hour documentary
tonight 26 March 2011 at 20:30 AEDT entitled "Zero Hour - Disaster
at Chernobyl".

[CraigS]

Yes Gary .. I've been up to other things lately, but looks like they've gotten things at Fukushima Daiichi back under control.

Unfortunate accident for these guys, though ..

Reference: IAEA (http://www.iaea.org/newscenter/news/tsunamiupdate01.html)

Also the radioactive plume off the coast has spread further, I believe.

Better news than over the last couple of weeks, though.

The main issue I guess, is the clean-up work ahead of them.

Cheers

[gary]

Hi Craig,

It was bad news to hear about the workers who were exposed to the high
levels of radiation and who may need to have treatment for burns over the
coming weeks.

Japan Broadcasting Corporation, NHK, have a story about them here, including
a video segment -
http://www3.nhk.or.jp/daily/english/26_03.html

[CraigS]

Hmm .. they were exposed somewhere in the range of 170 to 180 millisieverts, eh ?

The bigger problem is the spreading Caesium isotopes …

How do you avoid the stuff, if you're living there ?

Buy a Geiger counter ...?…
(They're probably as rare as hen's teeth over there at the moment).

Cheers
PS: Oops !! Sorry I was just reading the IAEA report of 24th March. They said that the workers got a dose of 170 - 180 mSv. A huge difference from 2,000 to 6,000 mSv !!
They stood in it for 2 hours !!???!!! Are these guys nuts ??

[CraigS]

IAEA report for the 25th March says:



This NHK report sounds a little suspect, methinks .. :question:

Cheers

[Sylvain]

The situation isn't improving much, on the contrary I'm afraid :(
Do you guys have any information as to why they cooling systems can't be turned back on? Is it that the pumps are dead? or they can't access them? or what?
I fear it might escalate...

[Analog6]

I'm very worried by the reports of levels 1000x normal in the sea off japan, and 80x for cesium 1437, with a 30 year half life, carcinogenic and accumulates in the food chain. That is the Pacific Ocean where our seafood comes from, after all. http://www.abc.net.au/news/stories/2011/03/27/3174814.htm

The thorium piece is extremely interesting - if Australia wants to pursue nuclear power why not this type of reactor?

And I suspect the pumps were damaged in the initial tsunami impact and/or when the power died and/or by later explosions.

And this from http://www3.nhk.or.jp/daily/english/27_11.html

"Higher level of iodine 131 detected in seawater
The Japanese government says radioactive iodine in excess of 1,850 times regulated standards was found in seawater collected near the troubled Fukushima Daiichi nuclear plant on Saturday.

On Friday, iodine 131 at a then-record 1,250 times regulated standards was detected in seawater collected in the same place 330 meters south of a plant water outlet.

The nuclear safety agency says there is no immediate threat to people within the 20-kilometer evacuation zone from the nuclear power plant.

The agency adds that seawater is dispersed by ocean currents and the contamination level will decline."

[gary]

Hi Craig,

Some certainly are.

An independent blog entry by Rachel Courtland entitled "Radiation Monitoring in Japan Goes DIY (http://spectrum.ieee.org/tech-talk/energy/environment/radiation-monitoring-in-japan-goes-diy)" on the
Institute of Electrical and Electronic Engineers (IEEE) "Spectrum" web site discusses
how some resourceful members of the general public in Japan are digitizing their
own Geiger counter readings and uploading them to the Pachube (http://community.pachube.com/) server.

The readings from various points across the country are then aggregated onto
maps which can be found on the Pachube web site here -
http://community.pachube.com/node/611



As Courtland reports in her blog -


Courtland's blog story can be found here -
http://spectrum.ieee.org/tech-talk/energy/environment/radiation-monitoring-in-japan-goes-diy

[CraigS]

Ha ! Fascinating, Gary !

Thanks for that .. who would've thought anyone would do that ?

Amazing !
(And a bit scary, too, I suppose ;) )
:)
Cheers

[CraigS]

Gotta chuckle (wryly) ... this one turned up this morning ..
Nuclear fears spark rush for radiation detectors (http://www.physorg.com/news/2011-03-nuclear-detectors.html)


Very predictable, I guess.

Cheers

[Octane]

Sounds like bad news this morning. From what I understand, a meltdown has occurred.

H

[gary]

Yesterday, March 29th 2011, Tokyo Electric Power (TEPCO) made their 9th release
of documents entitled "Detection of radioactive materials from the seawater
around the discharge canal of Fukushima Daiichi Nuclear Power Station".

They can be found here -
http://www.tepco.co.jp/en/press/corp-com/release/11032906-e.html

Here are some salient figures extracted from the reports -

In samples collected at 8:40 on 28th March -

30km north of the discharge canals of Units 5 and 6 -
Iodine 131 levels are 816 times the statutory limits.
Cesium 134 levels are 110.2 times times the statutory limits.
Cesium 137 levels are 73.9 times times the statutory limits.

In samples collected at 14:40 on 28th March -

30km north of the discharge canals of Units 5 and 6
Iodine 131 levels are 665.8 times the statutory limits.
Cesium 134 levels are 93.8 times times the statutory limits.
Cesium 137 levels are 63.5 times times the statutory limits.

Levels south of the plant are lower, but, for example -

10km south of the discharge canals for Units 3 & 4 -
Iodine 131 levels are 85.5 times the statutory limits.
Cesium 134 levels are 10.1 times the statutory limits.
Cesium 137 levels are 6.9 times the statutory limits.

For further numbers, interested readers should refer to the original reports.

Japan's national broadcaster, in a news story today, March 30th report -


That story and a video clip here -
http://www3.nhk.or.jp/daily/english/30_01.html


Meanwhile, inside the plants themselves, NHK report today, March 30th -


That story and video clip here -
http://www3.nhk.or.jp/daily/english/30_07.html

NHK also have a story dated March 29th that includes a video clip with graphics showing the trenches
that are filled with radioactive water that is of a concern to authorities.
See http://www3.nhk.or.jp/daily/english/29_18.html

[CraigS]

Hi Gary (& all);

It seems that the pumping situation has not yet brought the temperatures across the reactors, fully under control at Units 2, 3 and 4 yet, either.

IAEA says:


Tricky to interpret what al this means in terms of the criticality level.

IAEA says:


..and all this is apart from the worker casualties which have occurred, and the contamination of the water table and the offshore environment.

[SkyViking]

Not good news:

Article here: http://edition.cnn.com/2011/WORLD/asiapcf/03/31/japan.nuclear.reactors/index.html?iref=NS1

With I-131 having such a short half-life it's obvious that radioactive material is being leaked constantly from somewhere.