Fukushima: information and report on the nuclear accident

[Remundo]

Boh is researchers civil servants (INRS, CNRS, CEA ...). They cost the same price whether fast or slow, effective or not.

As to whether their pay is counted on the budget of the nuclear industry

[dedeleco]

I have the impression that Japan is currently hiding its problems because an earthquake 6,2 force took place right under Fukushima and they do not talk about nhk!
Amazing, they must have huge problems on their rickety power station, and more than one word as if everything was perfect !!
http://lesmoutonsenrages.fr/2011/11/27/ ... n-7-jours/
http://www.japanquakemap.com/week
http://www3.nhk.or.jp/daily/english/20111126_03.html
http://www3.nhk.or.jp/daily/english/society.html

[Christophe]

Troll mode: well, one more or one less: there is not much to destroy there ...

Realistic mode: I think it's been months that there is a media omerta on the subject ... because nothing is resolved at the moment and the plant continues to flee as in the first weeks not?

It should search on Twitter (facebook?) Or blogs of Japanese ... to take the info directly to the source ...

Here you go on the moutonsenrages.fr (discovered this weend)

[Remundo]

speaking of Omerta and misinformation ... a video to listen to ...
http://www.youtube.com/watch?v=LKV4chKI ... e=youtu.be

This video is part of a confrontation at Kyoto University on October 1er between Dr. Sentaro Takahashi, Deputy Director of the Reactor Reactor Institute of Kyoto University, and the students of the University of Kyoto. Kyoto who are members of the Zengakuren (National Federation of Students on Self-Government Associations).

Dr. Takahashi was responsible for organizing the public lecture by Dr. Yoshiya Shimada of the National Institute of Radiological Sciences, who is known for his assertion that exposure to radiation up to 100mSv / year is without danger.
The students were opposed to the conference, but Dr. Takahashi decided to go ahead and refused to let them in.

For those who have not taken Japanese LV2 is subtitled and it is edifying. The premonitory vision of what will happen in France in a few years or decades.

[Christophe]

Jancovici also talks about 200 mSV / an it seems to me ... While the legal tolerance in France (and elsewhere?) Is 20 mSV / year ...

The Japanese mustachio keeps its cool and the other too! In France they would have come to blows ...

After all we must not be equal to the risks of low doses (but this is another debate)

An interesting report from IRSN on the formation of the corium and its penetration through the concrete slabs dice or even in the ground.

http://www.youtube.com/watch?v=sI09NDpiBP4

Integrated on the site in a news with some links to other econo pages that are going well: https://www.econologie.com/reacteur-nucl ... -4378.html

[Did67]

Read this today: http://www.lemonde.fr/planete/article/2 ... _3244.html

[Remundo]

indeed, as it is the turmoil on the atom market, it might be better to get back in the wind ...

[Christophe]

Roh you missed a nice word game there: The wind turns!

Areva was already placed in the wind turbine before Fukushima.

Just as Total has some interests in solar photovoltaic (Shell and BP also but strangely no oil has never made solar thermal ... to my knowledge).

[Christophe]

http://sciences.blogs.liberation.fr/hom ... shima.html

FUKUSHIMA: NEW REACTOR ANALYSIS

While the huge and complex construction site continues on the devastated nuclear power plant of Fukushima Dai-ichi, engineers, physicists and chemists are looking into the accident.

What really happened in the reactors? How much fuel has melted? Have the coriums (the melted part of the fuel and the metal structure) gone through tanks and enclosures? If so, in what quantities? And what was the amount of radioactivity emitted?

Among the last elements delivered on these subjects, first scientific articles appear on the radioactive emission, with quite different calculations of the estimates made 8 months ago (I will treat this question in another note tomorrow). And the TEPCo engineers yesterday unveiled their latest assumptions about the state of molten hearts. According to them, the most pessimistic assumption is, with a 100% melting, that the corium of reactor No. 1 would have pierced the tank, but not the confinement enclosure in concrete and metal that is below.

It may seem surprising that these questions are still ... questions, more than eight months after the accident. But it is that the scientists who treat them are not satisfied with the answers already given, because they are often uncertain and imprecise.

For example, the fusion of the reactor cores has been considered certain since the very beginning of the accident. As early as March 13 (read this note), I wrote that the detection of cesium in the air involved at least the beginning of melting of the hearts, without it being quantifiable at that time. Then, as early as March 15, I wrote that this merger - "partial" because we could not quantify it - was "confirmed".

On the other hand, the portion of the fuels that has melted and the location of the corium - especially since it may have separated into several parts and now be found in several places (tank, enclosure, under the enclosure ???) remain difficult to establish. This is not surprising, since in the case of the Three Miles Island accident, it is only 7 years after the amount of melted heart could be established as well as the precise localization of the corium. The reactors are inaccessible for the moment, and therefore only analyzes and models can provide answers ... which do not have the certainty of an observation in situ by a robot.

In an analysis report (it's here but in Japanese so I'm working from English summaries and graphs) made public last night, Tepco is putting forward a scenario where the reactor fuel 1 has completely melted, pierced the tank and fell on the concrete part of the containment, crossing it to a depth that could reach 65 centimeters. See the graph on the right.

The molten fuel would thus be found in places at 37 centimeters (this is a calculation not a measurement) of the steel hull, itself surrounded by a concrete building resting on a slab 7,6 meters thick ( the "write off"). This scenario is for the engineers and physicists of the TEPCo the "worst case" .... but it could well be that it is about what actually happened between March 12th and 15th.

In this case, however, the corium would not have left the containment and would not have fallen on the floor. This part of the scenario is rather supported by the fact that such a phenomenon would have resulted in explosions of steam and chemicals (there was water, and the concrete would have been attacked).

For the reactors N ° 2 and N ° 3, the scenario would be the one represented on the graph of left. Part of the fuel melted, pierced the tank and began to fall on the concrete, gnawing only a few centimeters because in smaller quantities than the reactor No. 1. The spilled water would then have stopped the erosion of the concrete.

Attention, these are calculations, computer simulations, based on various measurements made by control instruments. For now, no direct observation of the reactors is possible and it will take years to achieve this.

This document contains two other graphs that can be used in spite of the language, which relate to the temperature measurement points and to the latest operations conducted to cool the coriums.

The graph opposite shows temperature measurements from March 22 to November 17, as well as measurement points. We can see that temperatures are around 100 ° C from the beginning of May. Then go under the 50 ° C in November.

Another graph (below) zooms in on the last period between October 18 and November 17 for one of the reactors. It shows that the Japanese considered that they could control a "cold snap" by slightly increasing the water flow at the end of October and shows that the cold shutdown of the corium is roughly achieved. The term is of course abusive, because a true "cold shutdown" of a normal reactor allows the unloading of the core to begin. In this case, it is impossible. Be careful, the temperatures are not those of the molten fuel, which is hotter, but of the measurement points of the instruments.

It may seem a bit futile to try to understand in detail what happened during the accident, given the extent of the devastation, but it could play an important role in determining strategies for future dismantling. destroyed reactors. It also affects another subject: how much radioactivity was emitted during the accident and in the days that followed? I will come back to it tomorrow.

By Sylvestre Huet, the 1 December 2011

[stipe]

It may seem a little futile to try to understand in detail what happened during the accident.

I note :
- the great precautions and the conditional, to signal that we do not know anything, we estimate ...
- That for this journalist the accident is over, which is not the case ...
if not :
http://fukushima.over-blog.fr/

According to Tepco, the 69 tonnes of fuel would have remained in the containment, gnawing the concrete only to a depth of 65 cm. In this configuration, the corium would not have left the containment. It remains to explain why the 31 march, the water table to 15 m under the reactor was seriously polluted by iodine-131.

Anyway, the strategy seems clear to me now ... Little by little we recognize what really happened by diluting the bad news in time, it will pass better.
Maybe in ten years we will have a chance to know the state and the real position of the corium of this factory ....