8.9 earthquake in Japan: tsunami warnings

[Astronuc]

I don’t know if this is a 'translation issue'? But as I interpret this they mean the "Japan(ese) plant in peril" = Fukushima I

?

It's probably a translation issue, but then I'm sure there are those who will claim that all BWRs with Mk I containment are at risk. That is not necessarily the case, the the operator of those units will not be reviewing their individual situations to ensure that this will not be the case.

I'm sure folks are looking at the EDGs and backup, and at the vulnerability of the spent fuel pools.

 

[turbo]

I think the helicopter reports are in regards to the spent fuel ponds. A few helicopters dumping water could keep the spent fuel from being exposed without risking personnel.

More than a few. Let's say that the spent fuel pond is 40x40x40. That comes out to 64,000 cubic feet. If half of the water had either boiled away or leaked out due to a rupture, that means that 1,984,000 lb of water or 992 tons of water has been lost. If the authorities could get near the pool with a snorkel truck, they might have the capability of pumping in enough water to keep up with boil-off, leaks, etc.

But, we don't know the extent of water-loss in the pool, and are unlikely to actually find out until TEPCO gets this under control.

 

[DevilsAvocado]

It's probably a translation issue, but then I'm sure there are those who will claim that all BWRs with Mk I containment are at risk. That is not necessarily the case, the the operator of those units will not be reviewing their individual situations to ensure that this will not be the case.

I'm sure folks are looking at the EDGs and backup, and at the vulnerability of the spent fuel pools.

Many thanks Astro for your balanced answer! We definitely need more of that in this thread...

My only intention with the link was to provide dlgoff with supplementing info on GE Mark 1 in the U.S. That’s all.

As I understand – this is a terrible catastrophe now, but we will get new info that we never had before, and that will make everything safer in the long run.

 

[FlexGunship]

I reserve the right to sound like an idiot here, but if they were able to pump anything directly into the primary cooling loop around the reactor core, why wouldn't they be pumping in water laced with a neutron-absorbing material?

As boron sediment formed around the fuel rods perhaps the heat would die down enough to at least prevent a meltdown. As I understand it, control rods are replaced less frequently than the fuel rods. This either means the control rods are used very infrequently or that the neutron capacity of the control rod material is high enough to out last the fuel rods themselves.

I'm kind of guessing, and I'm only skimming the 23 page thread (an act I hate when perpetrated by others).

 

[nismaratwork]

I reserve the right to sound like an idiot here, but if they were able to pump anything directly into the primary cooling loop around the reactor core, why wouldn't they be pumping in water laced with a neutron-absorbing material?

As boron sediment formed around the fuel rods perhaps the heat would die down enough to at least prevent a meltdown. As I understand it, control rods are replaced less frequently than the fuel rods. This either means the control rods are used very infrequently or that the neutron capacity of the control rod material is high enough to out last the fuel rods themselves.

I'm kind of guessing, and I'm only skimming the 23 page thread (an act I hate when perpetrated by others).

They have been mixing the seawater with Boric Acid for just that reason, but all that does is (hopefully) prevent a criticality incident. I don't know how well that hold for the spent rods in pools... especially if they've been scatterd by explosions and more.

 

[FlexGunship]

They have been mixing the seawater with Boric Acid for just that reason, but all that does is (hopefully) prevent a criticality incident. I don't know how well that hold for the spent rods in pools... especially if they've been scatterd by explosions and more.

Hmm, okay. I'm glad they took my advice.

I've actually been curious about this. My uncle is a nuclear engineer, but I rarely get to talk to him. The fuel rods are actually in the form of stacked pellets (as I understand). If that's the case, wouldn't it be conceivable to eject (via gravity) the pellets from each rod down shafts into storage containers laced with neutron-absorbing material? Or even just shape the bottom like a cone so the pellets had a tendency to fall away from each other. If the shafts were angled away from each other slightly, the divergence of the fuel rods alone would help to prevent criticality.

In an event like this, it seems that the reliance on active emergency control systems is the fundamental flaw. But no tsunami or earthquake would cause gravity to fail. I guess you need a hydraulic door to open the bottom of the fuel rod receivers, so that could fail. But maybe you make it accessible to some external motive power.

I dunno... this is that classic: "well, if I had designed it..." with a little bit of "Captain Hindsight" thrown in.

[PLAIN]http://captainhindsightsays.com/wp-content/uploads/2010/11/captain-hindsight1.jpg

 

[nismaratwork]

Hmm, okay. I'm glad they took my advice.

I've actually been curious about this. My uncle is a nuclear engineer, but I rarely get to talk to him. The fuel rods are actually in the form of stacked pellets (as I understand). If that's the case, wouldn't it be conceivable to eject (via gravity) the pellets from each rod down shafts into storage containers laced with neutron-absorbing material? Or even just shape the bottom like a cone so the pellets had a tendency to fall away from each other. If the shafts were angled away from each other slightly, the divergence of the fuel rods alone would help to prevent criticality.

In an event like this, it seems that the reliance on active emergency control systems is the fundamental flaw. But no tsunami or earthquake would cause gravity to fail. I guess you need a hydraulic door to open the bottom of the fuel rod receivers, so that could fail. But maybe you make it accessible to some external motive power.

I dunno... this is that classic: "well, if I had designed it..." with a little bit of "Captain Hindsight" thrown in.

[PLAIN]http://captainhindsightsays.com/wp-content/uploads/2010/11/captain-hindsight1.jpg[/QUOTE]

Or... start with something like this? http://en.wikipedia.org/wiki/Pebble_bed_reactor

 

[Borek]

I reserve the right to sound like an idiot here

Good for you.

In an event like this, it seems that the reliance on active emergency control systems is the fundamental flaw.

That's not where the problem lies, reactor was correctly scrammed. Please read the earlier posts in the thread.

 

[FlexGunship]

That's not where the problem lies, reactor was correctly scrammed. Please read the earlier posts in the thread.

Well, I got that just fine. But there's still decay heat even when the control rods are fully inserted, right? So, regardless, the reactor could benefit from additional neutron-absorbing material.

I don't think my post was so information-less as to warrant admonishment. And if you read it, it was kind of a response to the way people haphazardly toss around the idea of "adding water to the primary cooling loop." Even with Nismar's clarification I don't actually think my post was useless. I apologize.

 

[Astronuc]

Well, I got that just fine. But there's still decay heat even when the control rods are fully inserted, right? So, regardless, the reactor could benefit from additional neutron-absorbing material.

The reactors are shutdown, as intended, by the control rods (which contain neutron absorbing material), which is their function. The problem isn't the fission reaction, which stopped, so adding more neutron absorber, will not address the problem, which is the decay heat.

The core is sealed in the pressure vessel, which is covered by the containment of reinforced concrete. The problem is one of getting cooling water to the core in order to cool the fuel by removing the heat generated by the decay of fission products. Ideally, that would be handled by a closed cooling system, but that some how got damaged by the earthquake/tsunami - the actual details of which we do not know.

The action then is to pump seawater (desparate action) into the pressure vessel to cool the fuel in the core. However, the system is no longer closed, and they have to vent steam through valves in order to prevent a build up of pressure that could damage the contaiment. The containment contains most radioactivity - except for the gases and volaties such as radioiodine, which get vented with the steam.

 

[FlexGunship]

The reactors are shutdown, as intended, by the control rods (which contain neutron absorbing material), which is their function. The problem isn't the fission reaction, which stopped, so adding more neutron absorber, will not address the problem, which is the decay heat.

The core is sealed in the pressure vessel, which is covered by the containment of reinforced concrete. The problem is one of getting cooling water to the core in order to cool the fuel by removing the heat generated by the decay of fission products. Ideally, that would be handled by a closed cooling system, but that some how got damaged by the earthquake/tsunami - the actual details of which we do not know.

The action then is to pump seawater (desparate action) into the pressure vessel to cool the fuel in the core. However, the system is no longer closed, and they have to vent steam through valves in order to prevent a build up of pressure that could damage the contaiment. The containment contains most radioactivity - except for the gases and volaties such as radioiodine, which get vented with the steam.

Astronuc, thanks!

I guess I misunderstood the term "decay heat" which I now understand to mean "residual heat" or the heat energy already stored in the reactor. I was taking it to mean the heat that is generated even when the reactor is "shut down." Given that you can't stop the actual decay of the fuel rods, I guess I had assumed there would still be a non-trivial amount of heat being generated.

The two points I bolded in your post were the points I believe I was confusing. I'm now more knowledgeable!

Further, I saw the challenge of getting new water into a highly pressurized system (if they are venting of steam from the inner most cooling loop, then surely there's not enough room to add more water without further pressurizing it), which is why I shared the (now silly) idea of:

if they were able to pump anything directly into the primary cooling loop around the reactor core, why wouldn't they be pumping in water laced with a neutron-absorbing material?

 

[nismaratwork]

Astronuc, thanks!

I guess I misunderstood the term "decay heat" which I now understand to mean "residual heat" or the heat energy already stored in the reactor. I was taking it to mean the heat that is generated even when the reactor is "shut down." Given that you can't stop the actual decay of the fuel rods, I guess I had assumed there would still be a non-trivial amount of heat being generated.

The two points I bolded in your post were the points I believe I was confusing. I'm now more knowledgeable!

Further, I saw the challenge of getting new water into a highly pressurized system (if they are venting of steam from the inner most cooling loop, then surely there's not enough room to add more water without further pressurizing it), which is why I shared the (now silly) idea of:

You're kind of right, it's just that beta decay isn't moderated by neutron poisons, it's all within the materials... I think.

Poppa Astronuc?

 

[Angry Citizen]

Neutron poisons exist to stop neutron chain reactions. It really doesn't stop any kind of actual decay, whether it be alpha, beta or gamma. These are different from the neutrons of fission -- alpha emission is essentially a helium nucleus, beta an electron (it's more complicated than that, of course), and gamma is just insanely powerful light. A neutron is a neutron -- an uncharged particle that is capable of being captured by fissile material, resulting in a split and further release of neutrons. The neutrons (and subsequently the actual uranium fuel) are not the problem here.

 

[Al68]

I guess I misunderstood the term "decay heat" which I now understand to mean "residual heat" or the heat energy already stored in the reactor. I was taking it to mean the heat that is generated even when the reactor is "shut down."

Decay heat isn't "residual" or stored heat, it's heat that is generated after the reactor is shut down, just not (directly) by fission. It's generated by the radioactive decay of fission products both during normal operation and after shutdown. And, as Astronuc pointed out, radioactive decay is unaffected by neutron poisons (or anything else).

 

[nismaratwork]

Ugh... just saw a video of a single house floating at sea... this is so ugly in so many ways. These poor people are absolutely traumatized, having seen so much fear, death, and suffering.

 

[Astronuc]

You're kind of right, it's just that beta decay isn't moderated by neutron poisons, it's all within the materials... I think.

Yes - the beta decay is unique to the specific nuclide, and we cannot speed it up or slow it down in situ.

Astronuc, thanks!

I guess I misunderstood the term "decay heat" which I now understand to mean "residual heat" or the heat energy already stored in the reactor. I was taking it to mean the heat that is generated even when the reactor is "shut down." Given that you can't stop the actual decay of the fuel rods, I guess I had assumed there would still be a non-trivial amount of heat being generated.

The two points I bolded in your post were the points I believe I was confusing. I'm now more knowledgeable!

Further, I saw the challenge of getting new water into a highly pressurized system (if they are venting of steam from the inner most cooling loop, then surely there's not enough room to add more water without further pressurizing it), which is why I shared the (now silly) idea of:

Once the reactor is shutdown and cools off a bit, the pressure is reduced. It will have some pressure because of the decay heat. Under normal operation, the plant uses power from the local grid (which was disrupted/lost). Then the emergency diesel generators should kick in (which they did) - BUT, the fuel supply to EDGs was disabled/damaged, so the EDGs quit. Ouch! Then batteries ran for a while, but then ran down. Meanwhile, we understand that they scrambled to get backup generation.

Now they are pumping seawater into the reactors and containment.

 

[hypatia]

Ugh... just saw a video of a single house floating at sea...

That was a very un-nerving video. So many dramatic photos are emerging.

 

[nismaratwork]

That was a very un-nerving video. So many dramatic photos are emerging.

Yeah... it's heartbreaking... just absolutely awful.

 

[russ_watters]

Not sure if you guys saw this, but on Sunday, the JSDF rescued a man from the roof of his house...which at the time was located about 10 miles off the coast of Japan. http://www.therepublic.com/view/story/8ab0b68aefbb49938079d2a7c8239ceb/AS--Japan-Earthquake-Roof-Rescue/

 

[dlgoff]

Not sure if you guys saw this, but on Sunday, the JSDF rescued a man from the roof of his house...which at the time was located about 10 miles off the coast of Japan. http://www.therepublic.com/view/story/8ab0b68aefbb49938079d2a7c8239ceb/AS--Japan-Earthquake-Roof-Rescue/

Wow. Check out all the debris that far out in their close-up picture of the man on the roof top.

http://www.therepublic.com/view/photos/8ab0b68aefbb49938079d2a7c8239ceb/110313012491/"

 

[Astronuc]

Man vs Mother Nature. Mother wins!

http://news.nationalgeographic.com/news/2011/03/pictures/110315-nuclear-reactor-japan-tsunami-earthquake-world-photos-meltdown/?source=link_fb20110315japan20pics

http://images.nationalgeographic.com/wpf/media-live/photos/000/332/cache/japan-earthquake-tsunami-nuclear-unforgettable-pictures-wave_33291_600x450.jpg

 

[Evo]

Wow. Check out all the debris that far out in their close-up picture of the man on the roof top.

http://www.therepublic.com/view/photos/8ab0b68aefbb49938079d2a7c8239ceb/110313012491/"

His wife didn't survive, that was mentioned in another article.

 

[Astronuc]

His wife didn't survive, that was mentioned in another article.

May she rest in peace, and may he not hurt so much.

 

[OmCheeto]

Cyclones and meteor strikes?

My own personal coincidence is that I've have been refreshing my knowledge of modern physics over the last few months. This weekend, I made it to chapter 30 - the section on nuclear reactions.

BTW, what does "nanaimo sheedonai" mean? All I get in Google is a reference to towns in Canada and Japan (nanaimo).

Freaky. I did not make the connection between Nanaimo and Nanimo until you mentioned Canada.

And it took me awhile to figure out if what I was to reveal was still classified information.

Nanaimo is the town where 30 years ago, I was involved in the closest thing to a nuclear disaster I would ever experience.

A full loss of coolant flow to the reactor, with me at helm of the reactor control panel.

I must say, for a 22 year old, it was a brown stain moment.

Little did I know, 30 years later, I'd be reliving it.

 

[dlgoff]

His wife didn't survive, that was mentioned in another article.

May she rest in peace, and may he not hurt so much.

This whole thing is really getting to me.

 

[lisab]

This whole thing is really getting to me.

Me too, I'm getting to where I just can't process it, it's all so horrific. I can't imagine what the people living it must be going through...*shudder*

 

[Lacy33]

Me too, I'm getting to where I just can't process it, it's all so horrific. I can't imagine what the people living it must be going through...*shudder*

And to all of this, us too.
We just watched in part a video of the wave coming in and a group of people running up to the mass of rushing water and debris seeingly trying to help someone in the water and we think we saw that the wave may have taken the people trying to help as well. CNN cut off the viewing just before that might have happened.
I have to say, I have never seen any kind of humanity like that before and feel utterly ashamed to think i may have even begun to ever help anyone.

I just had to write this, in our family, we don't know what to say anymore.

 

[Newai]

Wow. Talk about bad timing!

Apocalyptic Video Games Delayed/Cancelled Due to Japan's Disastrous Events

Sony has postponed the PlayStation 3 racing game "MotorStorm 3: Apocalypse," which consists of user's racing through different areas that are being destroyed by natural disasters. The game was due to be released in Europe and Japan this week, and in the United States on April 12. While the U.K.release is still being discussed, it is unknown whether the U.S. release will be postponed as well.

...

While many video game companies have decided to delay certain games or characters, Tokyo-based video game developer Irem is the first to completely cancel one of its games due to the earthquake/tsunami in Japan. The game is "Zettai Zetsumei Toshi 4," better known as "Disaster Report 4" in the U.S., and it is a PlayStation 3 game that was set to launch in Japan this spring. But this game in particular seems to resemble the current situation too much, with an earthquake destroying a city in the very first scene.

http://www.dailytech.com/article.aspx?newsid=21135

[PLAIN]http://img191.imageshack.us/img191/3582/19030disasterreport.jpg

 

[jtbell]

CNN.com is reporting in a "breaking news" banner that workers at the Fukushima nuclear plant have suspended operations and evacuated.

 

[Lacy33]

CNN.com is reporting in a "breaking news" banner that workers at the Fukushima nuclear plant have suspended operations and evacuated.

What does that mean?