Nuclear accident in Japan, a Japanese Chernobyl?

[Former Oceano]

I just followed the link and the control rods go up hydraulically.

The thing is that if there is no more current to supply the cooling pumps, what energy will create or maintain this hydraulic pressure which will raise the bars?



In any event, in this diagram, the explosion is indeed that of the primary circuit with water at 299°C (470°F) pressurized to 69 bars (1000 psi). In addition, this superheated liquid is in contact with the nuclear fuel and therefore contaminated as much as possible.

Finally, if there is hydrogen, that means that the temperature of the water must have exceeded 750°C, there was enough for it to follow the pipes and go and explode outside...

Finally, if the temperature reaches 1135°C, the fuel melts...

And there it is the Chinese syndrome in Japan

[Leo Maximus]

A PDF about Fukushima dated today. History, list of incidents, links. (in English).

http://www.nirs.org/reactorwatch/accide ... tsheet.pdf

ML

[Christophe]

See my previous post. The Fukushima No. 1 is the oldest, it diverged into 1970. It's a General Electric BWR of 439 MW.

ML

Great, so here's the info: http://fr.wikipedia.org/wiki/R%C3%A9act ... bouillante ou http://en.wikipedia.org/wiki/Boiling_water_reactor



Indeed the turbine works on the primary unlike the French (Belgian?) REP which have 2 secondary: the turbine and the cooling:



http://fr.wikipedia.org/wiki/R%C3%A9act ... ris%C3%A9e

[Leo Maximus]

Under Wikipedia, reactor core meltdown lists:

http://fr.wikipedia.org/wiki/Fusion_du_ ... %C3%A9aire

In English (paragraph: "meltdown have occurred):

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

ML

[Former Oceano]

And yes, no secondary circuit given the information given by Maximus Léo...

So it's worse than my first intervention. It is necessary to hope that the bars are well mounted and that the heart is stopped because it sucks

In addition the absurd thing for me is the safety of the control bars which is due by an action. It takes pressure to raise them while the bars of our power stations have to come down which is 'easier'.

This is the difference between the brake circuits of an automobile (the pressure actuates the brakes=BWR) and of a truck (the pressure releases the brakes=PER). So this technology is not safe at all.

[Christophe]

Ok for technologies, good for news, forget politics; I only trust ASN and IRSN:

André-Claude Lacoste, Chairman of ASN, spoke to the press at 13 p.m. on the situation of nuclear power plants in Japan following the magnitude 8,9 earthquake that occurred on March 11 at 14:46 p.m. local time ( 6:46 a.m. French time). Agnès Buzyn, Chair of the IRSN Board of Directors, took part in this press briefing.

The ASN Chairman first underlined the seriousness of the situation in Japan and expressed his first thoughts for the victims of the tsunami.

He then recalled that it was not up to the French Nuclear Safety Authority to replace the Japanese Safety Authority or the Japanese operator in the management of the crisis.

The information available to ASN is fragmentary and incomplete. The efforts of ASN's natural interlocutors in Japan are in fact concentrated on dealing with the situation on site, which is changing rapidly.

During the earthquake on March 11, 11 nuclear reactors operating along the Pacific coast of Japan automatically shut down.

The main difficulties focused on the Fukushima nuclear power plant operated by the electrician TEPCO. They resulted from the loss of electrical power to the reactors and difficulties in cooling them.

Concerns then focused on reactor No. 1. An explosion occurred on the building of this reactor. ASN has asked IRSN to analyze the situation. The weather forecasts provided by Météo-France show that the wind is blowing in the direction of the Pacific. This point constitutes a favorable element in terms of protection of local populations against the risk of radiological exposure.

It is too early to define the lessons to be learned in France from this accident: the priority for the Japanese authorities is to manage the emergency phase. Lessons will be learned when the time comes and with full clarity.

With regard to the possible radiological consequences of this accident on French territory, a network of beacons for detecting radioactivity in the environment exists and makes it possible to identify any increase in radioactivity in a fine, precise manner and in real time. All the results of these measurements are centralized on the national measurement network and accessible to everyone on the website. www.mesure-radioactivite.fr managed by IRSN.

A new point will be made according to the evolution of the situation.

http://www.asn.fr/index.php/S-informer/ ... 11-a-16h00

ASN provides an update on the situation of nuclear power plants in Japan following the magnitude 8,9 earthquake that occurred on 11 March at 14:46 p.m. local time (6:46 a.m. French time).

The information available to ASN remains fragmentary. This is largely explained by the mobilization of its Japanese interlocutors on the management of the crisis.

From Friday 11 March morning and the start of the earthquake, ASN mobilized its emergency system and its teams. ASN is in constant contact with its technical support organization, IRSN, and analyzes in real time the information provided by its Japanese counterpart NISA, by the Japanese operator TEPCO and by the IAEA.

André-Claude Lacoste, President of the ASN, gave an update to the press today at 13:00 p.m. on the ASN premises in Paris. He first underlined the seriousness of the situation in Japan and expressed his first thoughts for the victims of the tsunami. He then recalled that it was not up to the French Nuclear Safety Authority to replace the Japanese Safety Authority or the Japanese operator in the management of the crisis.

In the afternoon of March 12, the Chairman of ASN, accompanied by the Director General of IRSN, took part alongside Ministers Nathalie Kosciusko-Morizet and Eric Besson in a press conference.

The latest developments in the situation known to ASN are the subject of an attached technical information note.

ASN will issue a new update depending on how the situation develops.

http://www.asn.fr/index.php/S-informer/ ... 11-a-21h00

Especially read:
http://www.asn.fr/index.php/content/dow ... ushima.pdf

[Christophe]

And yes, no secondary circuit given the information given by Maximus Léo...

So it's worse than my first intervention. It is necessary to hope that the bars are well mounted and that the heart is stopped because it sucks

Absolutely, it looks worse according to wiki:

The only wide-scale civilian nuclear meltdowns at nuclear power plants

* the Three Mile Island accident in Pennsylvania, USA, in 1979.
* the Chernobyl disaster at Chernobyl Nuclear Power Plant, Ukraine, USSR, in 1986.
* The Fukushima I Nuclear Power Plant at Fukushima, Japan, in 2011 [15]

The fusion of the core is therefore an incident according to Besson? Can't we sue a minister for defamation? No, that's just bullshit...

[Lietseu]

And yes, no secondary circuit given the information given by Maximus Léo...

So it's worse than my first intervention. It is necessary to hope that the bars are well mounted and that the heart is stopped because it sucks

Congratulations!
This is the plant that I saw!

Chrichri, don't take me for "softer knee" than I am! hi, hi, hi! (a diagram is easy to pick up and...to remember)

It seems that the reaction did not stop as expected, although theoretically the bars were removed...

In short, if we have a Three mile Ilsland in Japan, it will be a syndrome...Chilean?

Meow???

[Christophe]

Especially read:
http://www.asn.fr/index.php/content/dow ... ushima.pdf

Here is its contents, in bold the essential:

Technical information note on the situation of the reactors of the Fukushima Daiichi and Daini nuclear power plants (Japan) Saturday March 12, 2011 at 20:30 p.m.

I – Fukushima Daiichi Nuclear Power Plant

I.1 – Update on the situation of reactor no. 1
On March 11, 2011 at 14:46 p.m. (local time), an earthquake struck reactor no. 1 of the Fukushima Daiichi power plant, resulting in its automatic emergency shutdown.
The earthquake also caused:
- the loss of the two external power supplies of the plant which was not compensated by the emergency generators for reasons currently unknown;
- a tsunami which affected the pumping station of the nuclear power plant, a station ultimately allowing the cooling of the reactor (cold source).

This total loss of the reactor's external and internal power supplies led to the loss of cooling of the reactor core, cooling already altered by the loss of the heat sink.

The Japanese authorities quickly decreed measures to protect the population:
evacuation of people near the plant (2km radius) and sheltering (10km radius). The evacuation measure was later extended up to 20 km.

Following an increase in pressure inside the containment building (which reached 0,8 MPa) (= 8 bars), it was decided to carry out a voluntary decompression of this containment by a controlled and filtered discharge into the atmosphere. This operation was carried out on March 12, 2011 at 14:30 p.m. (local time) without any problem. The pressure inside the containment dropped to 0,4 MPa.

Around 14:40 p.m. (local time) detectors outside the site measured traces of cesium and then of radioactive iodine. This suggests degradation, at least partial, of the reactor core, which was later confirmed by the operator TEPCO.

At 15:36 p.m. (local time), a violent explosion took place in the upper part of the reactor building causing the roof to collapse. This explosion is probably due to
the hydrogen generated and then accumulated during containment decompression operations.

The Japanese government later stated that the containment nevertheless remained intact after the explosion.

Radioactivity measurements taken in the environment near the plant show a decrease in it after the explosion. The maximum values ​​reached, in terms of dose rate, were of the order of 1 mSv/h (i.e. the annual exposure limit for a member of the public – 1 mSv – is reached in 1 hour of exposure; for the record, in France, the
annual worker exposure limit is 20 mSv).

The weather forecasts confirm that the direction of the wind remains oriented towards the West, therefore towards the Pacific Ocean, which is a favorable element for the local populations.

At 20:20 p.m. (local time), the operator TEPCO initiated the flooding of the containment by injecting borated seawater into it; the expected duration of this operation is approximately 10 hours. This
will allow some cooling of the core (from the outside of the vessel).

The incident was classified by the Japanese Safety Authority as level 4 on the INES scale, which has 7 levels, which corresponds to a nuclear accident with local consequences. For
memory, the Chernobyl accident (Ukraine, 1986) corresponds to a level 7 and the Three Mile Island accident (United States, 1979) to a level 5.

I.2 – Update on the situation on reactors 2 and 3

Reactors 2 and 3 were automatically shut down during the earthquake. They have not been cooled for several hours. It would seem that the pressure in the containment of the
reactors is increasing. The opening of the depressurization valves of each containment of
containment is considered.

I.3 – Update on the situation on reactors 4 to 6

Reactors 4 to 6 were shut down for maintenance (unit shutdown) during the earthquake. TEPCO indicates that it does not have any safety problems with these reactors.


II – Fukushima Daini Nuclear Power Plant

The four reactors are shut down and all the control rods have been inserted. In addition, external power supplies are available.
It would seem that for one of the reactors, there was a pipe rupture in the containment enclosure.

The Japanese authorities have decided to evacuate the public within a radius of 10 km.

At 23 p.m. (local time), the situation was as follows:
• Reactor 1: The water level is stable (thanks to the injection of water by the Make-up Water Condensate System). An increase in pressure appeared in the containment building and the operator prepared for voluntary decompression of the containment.

• Reactor 2: The water level is stable (thanks to the injection of water by the Make-up Water
Condensate System). An increase in pressure appeared in the containment building and the operator prepared for voluntary decompression of the containment.

• Reactor 3: The water level is stable. An increase in pressure appeared in the containment building and the operator prepared for a voluntary decompression of
the enclosure.

• Reactor 4: The water level is stable (thanks to the injection of water by the Make-up Water
Condensate System). Water is additionally injected by the Reactor Core Isolation Cooling System.
An increase in pressure appeared in the containment building and the operator prepared for voluntary decompression of the containment.

• The radioactivity measurement beacons around the site did not detect any increase in radioactivity compared to the usual level.

[Christophe]

(a diagram is easy to pick up and...to remember)

Absolutely, it's pkoi we looked for it, and found it

ps: what are these metaphorical syndromes, speak clearly please