Japan: Explosion at Reactor No. 4

Japan: Explosion at Reactor No. 4

www.reuters.com

(Reuters) - Radiation levels around quake-stricken nuclear reactors in northeastern Japan are rising but there are no plans to extend the 20-km evacuation zone, the government said on Tuesday.

An explosion at the No. 4 reactor likely caused the new radiation which could rise to levels that may affect health around the reactors.

(visit the link for the full news article)



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Wow... nothing left to blow up.

There were 50 workers on-site working to pump water into the reactors. I hope they are OK.

There were reports earlier from the Japanese Cabinet Minister that reactor #4 was on fire. Now it has exploded.

Still waiting to see if footage of #2 explosion emerges.

www.reuters.com
(visit the link for the full news article)

I'm still trying to sort through the conflicting reports regarding meltdowns and the other reactors.

Surely, an explosion is a terrible event, and I'd assume there is no longer personnel pumping water, so do we assume meltdown is likely?

That's an incredibly brief article for a fourth explosion... and the PM did increase the evac zone, to 30 kilometers. So, part of that information is incorrect. I saw the "Breaking News" headline on Kyodo's scroll, but no other information over various sites or feeds.

I would like to say without any animosity that we all need to work together as a group and try and figure out what is really going on with these reactors. I am noticing quite a bit of bickering back and forth whether these explosions are a precursor to a full meltdown and also hearing alot of members saying that radiation levels aren't very high but as far as I'm concerned it is all, I repeat all speculation at this point. I personally would like to know whether or not we are in a bit of trouble or we will all be alright but we would never know if we keep arguing about who's right or who's wrong because in the middle of it all we could moss the most important evidence of all. Jut saying......

bbc news radio just updated that the japanese president was forced to give a statement that radiation has leaked, & is 4 times higher than "safe levels"
1 million japanese are without water or light

sorry, i can't provide "evidence" links etc - was just on radio :S

reply to post by Flyzoid


I completely agree! They say that "crowd-sourcing" is extremely powerful - let's prove it!

I posted this in another thread, but it has deteriorated into a bitching argument. I'll re-post here:

Here is what we know:

* Report: 20 km exclusion zone from Plant 1. Actual: 60 km (as of Saturday based on reporters blocked attempts).

* Report: Reactor 1 explosion didn't affect reactor. Action: exclusion zone set up.

* Report: radiation not a health risk. Action: exclusion zone of at least 20 km.

* Report: radiation not a health risk. Action: Iodine tablets given to everyone in area.

* Report: radiation not a health risk. Action: US Navy moves aircraft carrier located 80 miles off coast due to detected radiation.

* Report: Reactor 3 explosion didn't affect reactor. Action: exclusion zone extended to 30 km.

* Report: Reactor 2 damaged. Action: plant evacuated except for 50 workers.

* Report: Reactor 2 explosion. Action: unknown. No pictures of reactor 2.

* Report: Reactor 4 on fire. Action: unknown. No pictures of reactor 4 fire.

* Report: Reactor 4 explosion. Action: unknown. No pictures/video of explosion.

Please add to/amend this list. I tried to post the main points in chronological order.

Maybe we need a moderated research thread on time-lines and events/news reports with what we know?

I found some great videos on YT showing the various explosions and damage from a few angles that show what they are *saying* is happening is untrue, and is in fact much worse. There is also a satellite photo kicking around that shows the view after reactor #3 exploded.

Keep in mind that Japan has a history of cover-up on these matters. They can't be trusted to tell the truth.

reply to post by Flyzoid



i agree - it needs concerted & cooperative efforts...

this is what people were trying to do on the other main thread last night - trying to get to the bottom of conflicting news reports (about US army detecting radiation away from japan) - but some people are too ready to jump in & question things as it's happening in real time etc, rather than help get to the bottom of it

i know it's difficult, when sources are still being investigated for confirmation & legitimacy, for people to put faith in what's coming up on threads here... add panic & trolling to the equation, & things can get out of focus & muddied

reply to post by mirageofdeceit


good ideas about the time-line & dates

pc probs are really slowing me down, & i only have a radio :S

Okay, so since I'm not at the 20 post mark yet I won't be able to make a thread but I feel this may be a good point here. I have noticed in the last couple hours where I live FA/18 fighter jets flying above my house. Now while this isn't totally out of the ordinary( I am in the military). They never fly this late at night and never fly over residential areas unless they are practicing for airshow or doing fly by for the chargers game. This is not fear mongering, this is fact. I worked on miramar at a squadron as an aviation ordnanceman so I definitely know what's goes on daily and this is not normal.

What I don't understand is why can't they turn the damn things off? Or are they designed to give so much hell when the power is cut off? Isn't there some shutdown mechanism in place to prevent meltdowns?

reply to post by Flyzoid


Your input may be important to other people around you, keeping them informed with what is happening. Feel free to comment on any of my threads with anything you want to reach your 20 post mark!

No need to read them!

i just saw this.

"And news has just come in that there has been another explosion at the plant's Reactor No. 4."

www.arirang.co.kr...

"Radioactive levels "significantly" higher after plant blasts...... and the French embassy said a low level radioactive wind could reach Tokyo in 10 hours."

news.yahoo.com...

According to the BBC, reactors 4, 5 and 6 were offline at the time of the earthquake, and non-operational. They wouldn't have turned them on, so how can number 4 suddenly be able to be on fire and explode?

They say it's reactor 2.

www.bbc.co.uk...

www.bbc.co.uk...

A fresh explosion rocked reactor 2 at the Fukushima Daiichi plant - 250km (155 miles) north-east of Tokyo - in the early hours of Tuesday. Chief Cabinet Secretary Yukio Edano said, "Now we are talking about levels that can impact human health."

Mr Kan also said a fire had broken out at the plant's reactor 4. It now appears to have been put out."

I really feel for the Japanese people right now, this is the last thing they need to hear. Seems noone really knows what the hell is going on

Originally posted by frozenspark
What I don't understand is why can't they turn the damn things off? Or are they designed to give so much hell when the power is cut off? Isn't there some shutdown mechanism in place to prevent meltdowns?

Basically there are two types of rods in the reactor, the ones that cause a nuclear reaction and the ones that stop it, when a nuclear reaction is ongoing as in the plant is operating the control rods are up, as soon as the quake happened they pushed the control rods down stoping the nuclear reaction, but the nuclear rods are still extremely hot thats what they are having problems with, normally the cooling pumps would pump in cooling water to cool down the reaction that usually takes days or weeks to cool completely down but the tsunamy caused the

backup generators to fail that where outside of the plant so cooling water stoped being pumped, they have brought in aditional ones and are pumping in cooling water but the pumps have failed several times causing a build up of steam in the containment chamber, thats like a big steel pressure cooker, to prevent a breach they had to let the steam out which cause the top of the buildings to explode, that in itself is not a bad thing, this type of reactor has several containment layers, first you got the rods which are protected by metal, then they are inside the steel containment chamber, that chamber is surrounded by concreted and limestone, and then that

has a aditional concreted layer and then the building, at this point they think several of the reactors steel casing around the rods, so the first inner containment layer have breached letting some nuclear material leak into the steel containment chamber so the second layer, so they still have more layers to go trough before things get bad, as long as the last concrete layer is not breached were all good.

reply to post by frozenspark


No, the fuel rods remain extremely hot, and if they don't have time to cool, lots of time, then what is happening now happens.

Originally posted by frozenspark
What I don't understand is why can't they turn the damn things off? Or are they designed to give so much hell when the power is cut off? Isn't there some shutdown mechanism in place to prevent meltdowns?

These reactors are Boiling Water Reactors (BWR) type. Any nuclear reactor requires moderation. It basically slows down/absorbs neutrons emitted by the fuel (in this case, Uranium-235 and Plutonium-239).

Without moderation, an atom in the fuel rod emits a neutron, it flies into another atom, causing it to release more neutrons. More bombardments occur and more neutrons are emitted. This is known as a chain reaction. This causes the fuel rods to get hot, and this heats the water.

There are two parts to the moderation' neither are sufficient in isolation to stop the chain reaction. The first are boron rods. These absorb neutrons. The second is heavy water. This slows down the reaction as well as absorbing neutrons.

To shut down the plant, you fully insert all the control rods, and keep circulating the cooling water until the reactor is at ambient temperatures.

In the case of these reactors, the water is not being circulated. You still have the rods inserted, but this is insufficient. Initially, heat is generated from the by-product of fission of the fuel. If left unchecked, fission can start again. During this period the heat generated is increasing. The chain reaction can start again, and this heats the rods yet further. As they get hotter, they release more neutrons. This process accelerates like crazy. The water gets hotter and hotter (beyond limits), and turns to steam. The pressure keeps rising, as does the temperature. Eventually the water splits into hydrogen and oxygen. All that is left is for the hydrogen to gather in sufficient amounts for it to want to create helium or deuterium. When it does so, the thing explodes.

It doesn't stop there. Assuming sufficient material is left, it can melt the very materials that comprise the core, and the thing melts. This is a meltdown. It can occur before or after an explosion, but the conditions for an explosion exist prior to the temperatures required to melt the reactor (1400 degrees C at very high pressure is required to split water - the reactor components start to melt about 2000 degrees C).

That is the situation.

They are reporting that the hydrogen exploded outside of the reactor, but in the building, during venting of pressure (to lower the pressure in the reactor). This can't be so due to chemical nature of the hydrogen generation, and its reactivity. It is very likely to explode whilst still in the reactor due to the heat of the fuel rods (remember at this points the rods are exposed, and extremely hot - maybe 2000 degrees C). The hydrogen contacts these in sufficient quantity and BOOM.

Whilst the hydrogen is extremely volatile outside the reactor, it is unlikely to wait for the venting operation before deciding to fuse together. This is what makes all the reports of the all reactors being intact and all suffering the exact same problem at the same time (exploding only once the hydrogen was vented) so implausible.

There is some great footage of the aftermath of the explosion of reactor 3 on YT. There is clearly a void where the reactor should be. This proves beyond doubt that it was the reactor that exploded. It is much clearer on the TV.

I hope this clarifies sufficiently for you. It is late here, and there is a lot to type on the subject, but this should be a good start.

Please please puhhhleazee let there be no explosion in #3.
That is plutonium in there and makes the situation LITERALLY 20 thousand times more serious than Uranium.
Source: homepage1.nifty.com...

reply to post by xxPUSH0Noo


#3 Blew up in terrifying fashion almost a whole day ago. Sorry to say.