Fukushima Daiichi nuclear disaster

[audiotech]

A nuclear explosion? Absolute nonsense.

I'm no nuclear scientist and I'm relying on what was stated in the documentary by I assume nuclear scientists?

Are we to assume 'absolute nonsense' was kept secret for over twenty years by the Soviets and the West then, or is this 'absolute nonsense' too?

 

[laptop]

I'm no nuclear scientist and I'm relying on what was stated in the documentary by I assume nuclear scientists?

Don't assume, then! Hint: someone billed as "a nexpert" may well be making it up: someone billed as Professor of Nuclear Engineering at This Reputable Institution may be mad, but very likely knows what they're talking about.

Are we to assume 'absolute nonsense' was kept secret for over twenty years by the Soviets and the West then, or is this 'absolute nonsense' too?

Read again what Crispy said. You don't need to be a nuclear scientist to know that it's impossible to get a nuclear explosion out of a power reactor. A chemical explosion, yes...

 

[audiotech]

OK Prof.

 

[elbows]

Why are there four different animations?

Each animation has a different starting time. So the first one shows everything that travels from the area from midnight onwards, the 2nd shows everything from 6am onwards, etc.

 

[elbows]

The scale of the problem is slowly becoming clear.

http://www3.nhk.or.jp/daily/english/23_35.html

Radiation could affect people outside 30km zone
Chief Cabinet Secretary Yukio Edano says computer forecasts show that radiation leaking from a nuclear plant could pose a hazard to people outside its 30-kilometer zone.

Edano said at a news conference on Wednesday that a computer forecast system has shown that radiation levels in some areas outside the 30-kilometer zone would exceed 100 millisieverts, which is the level that could affect the human thyroid if a person is exposed to it outdoors for 24 hours.

Edano cited a lack of data and the need for more precise calculations, and said there is no need for immediate evacuation or to seek shelter indoors.

At the same time, he urged people living downwind from the plant to stay indoors as much as possible and keep the windows shut as a precaution.

The computer system, called SPEEDI, predicts how radioactive substances will spread in case of radiation leakage from nuclear power plants, based on measurements taken at various locations, prevailing winds and other weather conditions.

SPEEDI data can be used to draw up evacuation plans for residents around power plants in case of accidents.
Wednesday, March 23, 2011 18:55 +0900 (JST)

http://www3.nhk.or.jp/daily/english/23_28.html

Extremely high radiation found in soil
Japanese authorities have detected a concentration of a radioactive substance 1,600 times higher than normal in soil at a village, 40 kilometers away from the troubled nuclear power plant in Fukushima Prefecture.

The disaster task force in Fukushima composed of the central and local governments surveyed radioactive substances in soil about 5 centimeters below the surface at 6 locations around the plant from last Friday through Tuesday.

The results announced on Wednesday show that 163,000 becquerels of radioactive cesium-137 per kilogram of soil has been detected in Iitate Village, about 40 kilometers northwest of the plant.

Gakushuin University Professor Yasuyuki Muramatsu, an expert on radiation in the environment, says that normal levels of radioactive cesium-137 in soil are around 100 becquerels at most. The professor says he was surprised at the extremely high reading, which is 1,630 times higher than normal levels.

He warns that since radioactive cesium remains in the environment for about 30 years it could affect agricultural products for a long time. He is calling on the government to collect detailed data and come up with ways to deal with the situation.
Wednesday, March 23, 2011 19:02 +0900 (JST)

Have also seen a story about neutron beams detected but am at work right now with no time to look into this further.

 

[laptop]

Have also seen a story about neutron beams detected...

First image that evokes is fuck-off big holes, lined up, in primary and secondary containments... with something near criticality inside

Hope it's a misreport... or there's another way of getting a neutron beam...

 

[elbows]

OK then, detail is sparse but here's what we have so far:

http://english.kyodonews.jp/news/2011/03/80539.html

Neutron beam observed 13 times
Kyodo News
Tokyo Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of its crippled Fukushima No. 1 nuclear plant.

Tepco said the neutron beam measured about 1.5 km southwest of the plant's Nos. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour. This is not a dangerous level of radiation, it added.

The utility said it will also measure uranium and plutonium, which could emit a neutron beam.

In the 1999 criticality accident at a nuclear fuel processing plant run by JCO Co. in Tokai, Ibaraki Prefecture, uranium broke apart continually in nuclear fission, causing a massive amount of neutron beams.

In the latest case at the Fukushima No. 1 plant, a criticality accident has yet to happen.

But the measured neutron beam may be evidence that uranium and plutonium leaked from the plant's nuclear reactors and spent nuclear fuel have discharged a small amount of neutron beams via fission.

 

[laptop]

Ah, "beam" is mistranslation or misunderstanding. We hope.

But they've detected U or Pu off site by their neutron emissions

 

[Dr Jon]

I'm no nuclear scientist and I'm relying on what was stated in the documentary by I assume nuclear scientists?

Are we to assume 'absolute nonsense' was kept secret for over twenty years by the Soviets and the West then, or is this 'absolute nonsense' too?

I think what was referred to was the possibility of a hydrogen or steam explosion if the reactor core melted through the containment floor to the water below, causing much more widespread contamination.

ETA
In fact, the other motive for tunnelling below the containment and to install cooling was to prevent the molten core doing the "china syndrome" thing and melting its way down into the water table.

I wonder if this is what has caused the contamination of water supplies in Japan?

 

[elbows]

I wonder if this is what has caused the contamination of water supplies in Japan?

The relatively mild contamination of water supplies much further afield is to be expected via contamination in the air.

 

[elbows]

They are hoping to revive a pump at reactor 3 by as early as tomorrow. The plan to do that at reactor 2 seems to have been thwarted by high radiation levels, at least we get a number with which to judge how bad it is at this location:

At the No. 2 reactor, workers have been unable to replace a pump to help revive its internal cooling system since Friday as high-level radiation of at least 500 millisieverts per hour was detected at its turbine building, the spokesman said.

Taken from this story which is a reasonable summary of the recent news.

http://english.kyodonews.jp/news/2011/03/80585.html

 

[ATOMIC SUPLEX]

They are hoping to revive a pump at reactor 3 by as early as tomorrow. The plan to do that at reactor 2 seems to have been thwarted by high radiation levels, at least we get a number with which to judge how bad it is at this location:



http://english.kyodonews.jp/news/2011/03/80585.html

What on earth is going to happen with reactor 2 if they have not been able to able to do anything since Friday?

 

[elbows]

What on earth is going to happen with reactor 2 if they have not been able to able to do anything since Friday?

Well they've still been nursing it from a distance during this time, but yeah the high radiation levels at the turbine building will reduce some of their options. Im not knowledgable and many of the ins and out with the design of the plant so I cant really speculate on any details. Plus there is just so much detail we dont know. We have been given a lot more timely info than I would of hoped for, but I expect there is still plenty that they are aware of or suspect, that has not been talked about in public very much yet. Questions with big ramifications still exist for all 4 of the reactors we've been hearing most about, I may talk about each of these reactors and the questions a bit later, but certainly the number 2 reactor could be especially grim. Or not, its that hard to know which of the concerns will simply fade out and which incident will go down in history as the most serious one at this point.

For all that we do know, we dont really have a great sense of how much radioactive material continues to leave the site by air, nor what the major sources are. Theres a range of suspects and possible scales of pollution disaster, and beyond some superficial speculation in the press and the occasional comment from an expert who isnt just hell bent on either playing everything down or hyping everything up, I believe we still dont know enough to jump to any conclusions, although when fresh news or data comes out it is very tempting to.

 

[elbows]

Well I havent been able to find any decent english news about the neutron measurements yet, tried searching for news in Japanese, found one article that mentioned the issue and may have contained a little more info but I couldnt really tell as the translation was poor and too easy to read in a misleading way.

 

[story]

Excuse my stupidity: please explain what a neutron beam is and how it could be significant in this situation?

Google is not helping my understanding on this one.

 

[elbows]

Well as laptop suggests, its quite probably that the word beam is misleading. In which case what they mean is that neutron radiation was detected at some location around the nuclear site perimeter on various occasions. And this in turn means that some substances which emit neutrons are present in the environment there, which means some bad substances beyond the ones mentioned in past news have escaped from one or more reactors and/or spent fuel pools. Its not hugely surprising considering all that has happened there in recent weeks, but it gives us a hint that at least one of the less optimistic estimates for the state of things and what damage has been done to reactor fuel is true. Need a lot more data to say much more than that I would think.

 

[elbows]

Some US study of radiation levels in quite a wide area around the plant. Seems to confirm the greater radioactivity to the north-west of the plant, which other contamination data from the ground has often pointed at in recent days. Readings were taken some days back so it would be interesting to see a later version to see if the change in weather has made a difference. This in turn would also give a clue as to whether a large amount of stuff is still escaping or whether most of the contamination shown in this data came out during specific events much earlier on, which happened to coincide with winds taking stuff north-west, and/or rain bringing the substances down to earth at those times & places. Ugh Im tired, not sure if Im making sense, what I mean is that if there is still lots of new stuff escaping then when the winds changed direction completely and rain fell in various places, we would expect to see this on a map made using more recent data than this particular study.

http://blog.energy.gov/content/situation-japan/

 

[laptop]

Excuse my stupidity: please explain what a neutron beam is and how it could be significant in this situation?

Google is not helping my understanding on this one.

To add a bit:

Where does neutron radiation - that is, neutron streams of particles - come from?

Mostly, in this context, from the nuclei of atoms of uranium or plutonium splitting spontaneously, producing in each case neutrons plus two nuclei of lighter elements (this is where the cesium, iodine, etc come from).

So if you detect a low level of neutrons running around, you've detected uranium or plutonium (or possibly other elements that complicate shit), just lying around.

BUT I first read the word "beam" to imply a lot of neutrons, all going in roughly the same direction. How would you get that?

From chain reaction.

One atom of uranium-235 splits, and emits 2 neutrons. If they're absorbed when they collide with other uranium atoms they split those two, which emit 4 neutrons, which if absorbed split 4 more U-235 atoms, producing 8 neutrons...

If the U-235 is dense enough, you got yourself a runaway chain reaction - a nuclear explosion. To do that, you generally take a very precise sphere of nearly pure U-235 ("weapons-grade uranium") and hit it very hard all over at precisely the same instant - by "precisely" I mean within a nanosecond (1/1,000,000,000 second) - to squash it to be dense enough.

This is very hard to do, in three or so ways. Which is why Andorra and the drug cartels don't have nuclear weapons. We hope.

If the uranium is not dense enough, lots of those neutrons escape and you don't get a runaway reaction. If you manage to ensure that exactly one of the two neutrons is absorbed - slowing them down by passing them through a "moderator" (water, or in the case of Chernobyl or Sizewell A, graphite) and absorbing spare ones in boron rods - then you have yourself a steady-state nuclear reaction, suitable for boiling water.

Doing this so that it keeps going but doesn't get over-excited and melt down is a bit tricky, in a balance-a-pencil-on-its-point kind of way.

And if you open a hole in the side of that reactor, you get a beam of neutrons.

Here endeth the lesson.

 

[story]

Thanks for that laptop. I'm learning lots.

Logic and common sense were telling me it must be something like that, (not all the technical stuff, but about a "beam" implying a single relatively large source, and that being a Very Bad Thing) but being ignorant, I thought I'd better check.

Urban teaches.

 

[two sheds]

Yep and thanks for all the updates too, elbows.

 

[elbows]

Cheers.

Todays news in brief:

Tokyo water Iodine levels have fallen back below the limit for infants drinking the water. (think the actual legal limit might be for baby milk)

2 workers injured at unit 3 when their feet came into contact with radioactive water. They hae gone to hospital and a 3rd worker was affected but did not need hospitalisation.

Unit 1 reactor pressure got too high so they stopped pumping as much water in, pressure now said to have fallen.

Some spent fuel pool temperatures that are, I presume, gleaned from the use of infra-red imagery, are said to have fallen.

A temperature reading for unit 4's spent fuel pool has appeared in the stats for the first time, said to be 100C (!) at 02:40 JST March 24th.

Unit 2's spent fuel pool temperatures, which have ben available since Monday, continues to lurk around the 50C level.

Unit 5 & 6 have the following news which I dont yet fully comprehend: 'The pumps for Residual Heat Removal (RHR) was automatically stopped when the power supply was switched from the temporary to the permanent. (17:24 March 23rd)'

They have the lights back on at another control room (maybe unit 1)

Seawater injection into unit 3's spent fuel pool is now being done via 'cooling and purification line' which sounds like progress but I've not seen this explained anywhere yet.

Source for most of the above data about the plant: http://www.nisa.meti.go.jp/english/files/en20110324-1-1.pdf

 

[kyser_soze]

Least hysterical coverage of What's Happening on the web, elbows & laptop.

 

[ATOMIC SUPLEX]

Cheers.

Todays news in brief:

Tokyo water Iodine levels have fallen back below the limit for infants drinking the water. (think the actual legal limit might be for baby milk)

2 workers injured at unit 3 when their feet came into contact with radioactive water. They hae gone to hospital and a 3rd worker was affected but did not need hospitalisation.

Unit 1 reactor pressure got too high so they stopped pumping as much water in, pressure now said to have fallen.

Some spent fuel pool temperatures that are, I presume, gleaned from the use of infra-red imagery, are said to have fallen.

A temperature reading for unit 4's spent fuel pool has appeared in the stats for the first time, said to be 100C (!) at 02:40 JST March 24th.

Unit 2's spent fuel pool temperatures, which have ben available since Monday, continues to lurk around the 50C level.

Unit 5 & 6 have the following news which I dont yet fully comprehend: 'The pumps for Residual Heat Removal (RHR) was automatically stopped when the power supply was switched from the temporary to the permanent. (17:24 March 23rd)'

They have the lights back on at another control room (maybe unit 1)

Seawater injection into unit 3's spent fuel pool is now being done via 'cooling and purification line' which sounds like progress but I've not seen this explained anywhere yet.

Source for most of the above data about the plant: http://www.nisa.meti.go.jp/english/files/en20110324-1-1.pdf

Not the stabilizing news I was hoping for, but that was never going to happen.
We are currently preparing to go but with an option to pull out at the very last minute.

 

[Barking_Mad]

Reuters:

A statement from the ISRN (Institute for Radiological Protection and Nuclear Safety) at 8 am this morning in Paris (France) on the reactor 3: "IRSN analyzes the potential causes of loss of containment of reactor No. 3.

One hypothesis discussed by IRSN is the possibility of a rupture of the reactor vessel followed by an interaction between the corium (a mixture of fuel and molten metal) and concrete at the bottom of containment. "

www.irsn.fr/FR/Actualites_presse/Ac...Seisme-Japon_Point-situation-24032011-08h.pdf

 

[Barking_Mad]

...

According to a story in the Mainichi News, the Nuclear Safe Commission of Japan has announced that persons within the 20-30km zone received a cumulative dose of 500 millisiverts during the first 12 days of the accident. In addition, some people outside the 30km zone received 100 millisiverts.

http://mdn.mainichi.jp/mdnnews/news/20110324p2a00m0na037000c.html

 

[elbows]

Can confirm that the control room light on is indeed unit 1. TV has reported steam coming from all 4 reactors early this morning, first time steam has been seen around unit 1.

Regarding unit 4 fuel pol temperature reading which showed up earlier. A subsequent release of data now shows 'incorrect indication' rather than a temp of 100C.

http://www.nisa.meti.go.jp/english/files/en20110324-2-1.pdf

 

[elbows]

...



http://mdn.mainichi.jp/mdnnews/news/20110324p2a00m0na037000c.html

Thanks for the link. I was complaining about this story in another thread yesterday, so its good to see some additional details, but specifically I find the following advice to be too vague:

"There is no need (for people living outside of the 30-kilometer radius of the nuclear plant) to evacuate or stay indoors immediately. The government recommends those situated in the lee of the power plant to keep their windows closed and seal themselves indoors," said Chief Cabinet Secretary Yukio Edano during a press conference on March 23.

 

[elbows]

The switching back on of some other MOX reactors in a different part of Japan has been delayed:

http://english.kyodonews.jp/news/2011/03/80802.html

Government considering asking people 20-30km from plant to move away, rather than stay indoors. They are saying its all about practicalities, which is at least partially true, but I think various readings in recent days also give cause for this consideration.

http://english.kyodonews.jp/news/2011/03/80801.html

The government is reviewing whether to continue its current directive for people living 20 to 30 kilometers away from a troubled nuclear plant in Fukushima Prefecture to remain indoors, with an eye on possibly recommending they relocate further away to make their everyday life easier over the long term, the top government spokesman indicated Thursday.

Chief Cabinet Secretary Yukio Edano noted in a news conference that reconsidering the directive does not mean the risk of radiation leaks from the plant is increasing.

''We've been informed about the difficulty of supplies reaching them,'' Edano said. ''We're reviewing whether people can continue living under the current conditions given that they've been living this way for a considerably long period of time.''

 

[ATOMIC SUPLEX]

Ahhhh, I was all ready to go. Now I am back to square indecisive.

 

[story]

What's happening to all the water that they're pumping in? Presumably it is becoming contaminated? Is it being collected in any way? Will it flow into the ground, water table, sea?