Japan Earthquake: nuclear plants

curie

Has anyone heard officially that there has been an upgrade to INES level 6? I've seen it around the web but it doesn't seem like a formal announcement.

rhody

Lefteris,

I am glad you found us, I just did a google search on the title to this thread and it came up in the top ten list, and to PF's credit , the folks here strive to provide as accurate and timely information as possible. I did a thread contribution count and it is over 250 members (many new because of the reactor disaster) and climbing (no bad pun intended).

Rhody...

havemercy

Following french ASN, the cooling of reactor n° 3 with pure water failed.

"Communiqué de presse n°20 du 25 mars 2011 à 10h00
25/03/2011 10:46"

"L’exploitant poursuit par ailleurs l’injection d’eau de mer pour refroidir les réacteurs n°1, 2 et 3. Une tentative d’alimentation du réacteur n°3 en eau douce a échoué, vraisemblablement en raison des conditions radiologiques d’intervention. "

http://www.asn.fr/

Borek

IMHO it is snowing, it is visible both in closeups and in some more general views. After all it is March 23rd, so nothing unusual.

jlduh

Ok, i would like to bring some more material here. Lots of things to summarize.

The first thing is that i just captured several shots from the live NHK world when they were talking about the 3 workers injured in the basement floor beacuse of the contaminated water. They we're asking a specialist from Tokyo University where this water could come from and he had a nice drawing which i think is a new important element for our analysis here because it seems quite accurate, and it's a transversal cut view through the reactor and turbine building. I let them big if no problem for the forum admins because it's much easier to see some details (the resolution is not excellent).

I post them first and will add infos and comments after.

1


2


3



I have a 4th one which completes the overall view of the buildings and layout which is a view from the top, a cut view also, at the level of the basement (i would say at the ground level approximatively).




Position of the workers injured by the highly contaminated 15cm to 30 cms water laying on the floor:

A) Based on the infos the guy from Tokyo University gave, the 3 workers were in the lowest room, between the torus room (on the left) and the turbine (on the right), where the blue pipe linking the reactor anf the turbine (steam pipe) goes down (on pictures 1 to 3).

B) the guy situated them on the other drawing (picture n°4) close to the big red inscription at the bottom right of the image (so quite far away from the reactor position).

The specialist interviewed also said that he doubts the water could come from the spent fuel pool (because of the level of contamination), but said it could come from a broken pipe coming from the reactor. He also said that the day before, an other shift reported no water here. Very surprisingly (for me), then didn't evoke the possibilty that this water could also come from the suppression pool which is almost at the same level just behind the wall on the drawing...

These drawings give some interesting informations, we see the level at which the suppression pool is installed (quite deep under the ground) but we also see that the turbines are actually well under the ground either!

That's really scary when you think about risks of flooding... By the way, this probably means that seeing the flooding of the plant from the helicopter shot (just after the tsunami), these rooms have been flooded also??? What do you think? Then they would have needed to empty them which could explain the time spent to access these areas?

I'm very surprised to see this kind of layout for the turbine an connecting buildings...

Right AntonL, we were guessing pretty well with the bits of infos everybody brings here. The puzzle is assembling.

Something else: looking at all these new informations on what's inside, i relate the position of the turbines and the position of the big hole in the roof of this turbine building: was this hole done by a big debris coming down after the explosion or was it done DURING the explosion by one of the turbines just blowing out? The hole is right at the top of the turbines:



EDITED: Coming back to the relative level of the torus and the turbine to the ground level, one can evaluate how deep these are below the ground level: the reactor vessel is (if no mistake) around 5,4m in diameter, the bottom of the torus (which not so far in diameter than the RPV) seems then to be at around -1,5 (and even more?) "reactors diameter" below the ground (sorry for this approximate unit of measurement, but at least no conversion units problems!). From the TEPCO tsunami study (which proved exact in showing the buildings below the ground! I was not understanding this... and not believing it! But their scale is misleading: the height of the platform relatively to sea level seems as high as the reactor building, which is obviously untrue!)



we got the info that the platform was at +10 to +13m from sea level. Soooo... do you come to the conclusion that the bottom of the plant floor (which is visibly the torus supported by concrete plots) is probably only a few meters above actual sea level???

Gilles

I don't really know what happens when corium meet a concrete slab - I think of some kind of reaction between silicates and molten metals, leading to further fusion of the slab. Not sure it is supposed to emit a lot of smoke : black smoke is usually associated with incomplete combustion of organic materials with emission of fine carbon particles (soot)- well they may be some rubber, isolated (!) cables, and so on, under the reactor, but I'm not sure this represents a large amount of material.

AntonL

Not Bad - as posted here


OK I made a mistake I thought is as upper level but now we know it is the basement

|Fred

I would like to point out a few thingy

March 20th
Reactor 3 Pressure = 250-290 KPa
PCV Pressure= 310 Kpa
Suppression Pool Pressure = over 400 KPa out of scale

Preparation to lower the pressure was carried. Judging from the situation, immediate pressure relief was not required.

March 23
Reactor 3 Pressure = 135-0 KPa
PCV Pressure= 100
Suppression Pool Pressure = down scale

March 24
Reactor 3 Pressure = 142-0 KPa
PCV Pressure= down scale
Suppression Pool Pressure = down scale

March 25th
Reactor 3 Pressure = 139- 0 KPa
PCV Pressure= 107 Kpa
Suppression Pool Pressure = 194 KPa
===========================================

I think that the Reactor pressure sensors are compromised, one likely dead.
the Down scale indicated a dé pressurization of the PCV.

AntonL

It must be a relative slow leak, I would imagine a valve not holding the pressure
and now the contaminated steam is escaping, which condenses to the water
the basement acting as a containment area.

havemercy

Sorry to step back regarding the neutrons. I heard that the water has the effect to slow down the speed of the neutrons.

If this is correct, in the Spent Fuell pool, the neutrons with high speed will go through the fuell without making contact with the fuell and thus reduce the nuclear reaction.

If they add water, it will reduce the speed of the neutrons that will making more contact with the fuell and then increase the nuclear reaction.

The fact to put water in the pools will accordingly have the effect of making more nuclear reaction, isn't it correct ?

|Fred

I edited my post as I did not gave it enough sensible thoughts :)

jlduh

@Havemercy: my understanding is that water (not bored of course) increases the reaction and that steam reduces it, and that this is a way to control the reactivity and the reactor in a BWR. But answers from specialists would clarify that...

Maclomer

In all of the reactors (setting aside the spent fuel pools) the absolute imperative is to maintain cooling by whatever means is feasible and, however it is done, active cooling will probably be needed for many months.

Right now we know some of the cooling is done by directing water jets onto the exterior of the containment and the runoff will go into the ocean. If the containment is breached, that runoff will be radioactive so then there is bound to be a continual emission by this route. Unavoidable.

Now my question:
To what degree is cooling water, and so it seems, seawater, being injected directly into the cores (for example Number 3) and is this water is being heat-exchanged in a closed loop; or are they injecting the water and then allowing the steam to escape (people have commented here about salt build-up)?

I ask this because, at the same time, we hear about 'restarting the cooling pumps', especially for Number 3, using this newly laid power line, which implies to me that an intact cooling loop with proper heat exchange may still be possible, at least for some of the reactors.

Gilles

I think water in general increases the reaction rate by slowing neutrons. It's just that water vapor is much less dense than liquid, so the effect of steam is to decrease the rate relative to liquid water (negative void coefficient). In reactors using graphite as a moderator like RBMK , it was positive , because water acted essentially as neutron absorber and not as a moderator. That's the same for Pu-Na fast breeder ...

|Fred

Reactor 1 (not compromised) but under heavy stress
Reactor 2 stabilized (may be wishful thinking)
Reactor 3 (compromised, not necessarily the vessel it self may be only in the pipe of the cooling system and the containgment)

artax

There's a long but interesting doc. here on spent fuel storage (wet and dry):-

http://www-pub.iaea.org/MTCD/publica...e_0944_scr.pdf

TCups

RE: IODINE PILLS & IODINE UPTAKE BY THE THYROID

Normal iodine will not, I believe, displace radioactive I-131 that has already been taken up by the thyroid gland. The purpose of the iodine pills is to effectively flood the normal biologic uptake of trace amounts of iodine with the normal, non-radioactive isotope, and suppress any further uptake of iodine, ie, radioactive iodine, by the thyroid. After a large dose of RAI (radioactive iodine), potassium iodide will do little good.