Japan's Nukes Following Earthquake

[namlive]

Sea water is 3.5% solids.  To get 90 tons of salt would require the evaporation of 2500 tons of seawater.  To evaporate that much water in 15 days would require about 6500 MW average power so I don't buy the 90 tons of salt claim.
I could buy that 90 tons of seawater - that could happen with 200MW of average power.
I wonder what their efforts to get freshwater to the plant are?   

The have been putting in 150 tons of seawater in one cooling shot. The 2500 tons is not out of reach.
Unit 3 has 6% MOX fuel. The rest do not from what I can tell. I am not sure if it will be an issue, other than the fact the reactor building roof is useless in unit 3. I remember sitting on the Peach Bottom fuel floor with my buddy Steve who said, "They spent 100 million dollars a piece to build these units and then they put a tin roof on it." (Actually corrugated steel.) I always wondered when the fuel pools being exposed as much as they are would bite the industry.

[Matthew B]

The have been putting in 150 tons of seawater in one cooling shot. The 2500 tons is not out of reach.

It has to be 2500 tons of evaporation though.  If the sea water is leaking back out, it will pick up salt and wash it away because sea water isn't saturated with salt.

[Sun Dog]

Unit 3 has 6% MOX fuel. The rest do not from what I can tell. I am not sure if it will be an issue

If you are interested in understanding what impact the presence of Mixed Oxide Fuel had, than get a copy of the ANS Technical Brief dated 03-25-2011 that was prepared by Michaele (Mikey) Brady Raap.

It clearly explains the impact MOX fuel had on the accident consequences at Fukushima Daiichi.

[Loffy Muffin]

I

t clearly explains the impact MOX fuel had on the accident consequences at Fukushima Daiich

No it don't.  It's nothing more then a weak sales pitch that addresses only the impact of MOX on cooling the fuel as compared to LEU.   With any luck, the article will stay internal to ANS.  The industry would be better served with critical questions and solid solutions then endless pollyanna articles. 

[Sun Dog]

I

No it don't.  It's nothing more then a weak sales pitch that addresses only the impact of MOX on cooling the fuel as compared to LEU.   With any luck, the article will stay internal to ANS.  The industry would be better served with critical questions and solid solutions then endless pollyanna articles.  

Being able to express differing opinions - one of the great things about America.  As far as the document staying internal to ANS, no it don't.

[Matthew B]

I have some doubt as to the source of the hydrogen in unit 4 coming from the spent fuel pool.  The fuel there was aged for 4 months before the accident so it would have cooled down considerably.

Unit 3 and unit 4 share a stack and ventalation system.  I wonder if the hydrogen was actually from unit 3?  Since the ventelation fans were off, when the vent from unit 3 was open, the steam and hydrogen would have been driven throughout the ductwork.  This could have resulted in a release of hydrogen into unit 4's reactor building.

[roadhp]

http://www-pub.iaea.org/mtcd/publications/pdf/pub1265_web.pdf

From Nuclear Street...
www.nisa.meti.go.jp/.../en20110320-4-2.pdf

http://www.iaea.org/Publications/Factsheets/English/ines.pdf
Gives a graphic and everything.

[hamsamich]

wasn't the unit 4 spent fuel pool on fire at one time?  that would cause bunches of hydrogen, right?  besides, uncovered fuel in a fuel pool will heat up unless it is really old.  4 months isn't enough time to think uncovered fuel won't heat up and cause hydrogen production unless I am missing something...

[Marlin]

Today's IAEA report is fairly detailed on unit status and worker exposure. I-131 and Cs-137 don't seem that bad in the surrounding areas, detectable and little above limits but not catastrophic. 200 to 600 rem to a couple of workers legs are a little higher than previous exposures.

http://www.iaea.org/newscenter/news/tsunamiupdate01.html

[matthew.b]

wasn't the unit 4 spent fuel pool on fire at one time?

Something on the top of unit 4 was burning, but since no one was in there I don't think they know for sure.  No doubt there is plenty of flammables up there to make a bunch of smoke.

  that would cause bunches of hydrogen, right? 

Burning of zirconium would not make hydrogen.  Hot rods in steam would. 

besides, uncovered fuel in a fuel pool will heat up unless it is really old.  4 months isn't enough time to think uncovered fuel won't heat up and cause hydrogen production unless I am missing something...

From what I understand, 4 months is at the edge of the window for heating enough to react the zirconium.  The elements no doubt would get very hot, but the temperature necessary is 1900°F.

[hamsamich]

yeah, but I mean buring rods combined with throwing seawater on them.  hot rods with seawater being put on them is what I am talking about.  didnt they pump seawater into the fuel pool?  seems obvious but maybe I am getting something wrong?

[HydroDave63]

Speaking of cold seawater on spent fuel pools and uncovered cores, any data on Na-24 found?

[Nuclear Renaissance]

I have some doubt as to the source of the hydrogen in unit 4 coming from the spent fuel pool.  The fuel there was aged for 4 months before the accident so it would have cooled down considerably.

Unit 3 and unit 4 share a stack and ventalation system.  I wonder if the hydrogen was actually from unit 3?  Since the ventelation fans were off, when the vent from unit 3 was open, the steam and hydrogen would have been driven throughout the ductwork.  This could have resulted in a release of hydrogen into unit 4's reactor building.

What happened to the presumption by TEPCO that the U4 refuel floor fire was from lube oil? Was that rescinded? I have problems seeing how U3 venting could've affected U4 - containment venting paths are via the stack, whereas reactor building ventilation has its own exhaust. It would've had to reverse down all way through Standby Gas Treatment; with how light H2 is, that seems to be a stretch.

I read today that the U3 hydrogen detonation had such force that it lifted the 200 ton-capacity crane and dropped it to the refuel floor, maybe impacting the pool. Geez.

[RRhoads]

What happened to the presumption by TEPCO that the U4 refuel floor fire was from lube oil? Was that rescinded? I have problems seeing how U3 venting could've affected U4 - containment venting paths are via the stack, whereas reactor building ventilation has its own exhaust. It would've had to reverse down all way through Standby Gas Treatment; with how light H2 is, that seems to be a stretch.

I read today that the U3 hydrogen detonation had such force that it lifted the 200 ton-capacity crane and dropped it to the refuel floor, maybe impacting the pool. Geez.

Uh, yea..that and like the detonation didnt suck some (not all but prob some) of that H20 outta the SFP..duh!

[matthew.b]

What happened to the presumption by TEPCO that the U4 refuel floor fire was from lube oil? Was that rescinded? I have problems seeing how U3 venting could've affected U4 - containment venting paths are via the stack, whereas reactor building ventilation has its own exhaust. It would've had to reverse down all way through Standby Gas Treatment; with how light H2 is, that seems to be a stretch.

I read today that the U3 hydrogen detonation had such force that it lifted the 200 ton-capacity crane and dropped it to the refuel floor, maybe impacting the pool. Geez.

I believe venting containment directly to the stack at the current early BWR units is a rework; the containment originally vented to the RB exhaust system.  The US units got the upgrade, but the Japanese units didn't.

If the containment venting was directly to the stack, then it would have gone right up the stack and never resulted in an explosion to begin with.

[Nuclear Renaissance]

I believe venting containment directly to the stack at the current early BWR units is a rework; the containment originally vented to the RB exhaust system.  The US units got the upgrade, but the Japanese units didn't.

If the containment venting was directly to the stack, then it would have gone right up the stack and never resulted in an explosion to begin with.

Do you remember where you saw that Japanese plants did not get the hardened vent mod to allow venting direct to the stack? I saw an recent interview with the NRC commissioner who said he didn't know if they had it.

There are many ways hydrogen can get into a Mark I secondary containment even if you are intentionally trying to send it up the stack - sustained high pressures in primary containment can force it through valve seats, leakage through HPCI/RCIC steamsides, operating RHR in steam condensing mode, etc. Also, to successfully vent primary containment to the stack, you must isolate the Standby Gas secondary containment suction dampers; normal position for those dampers is open, and I've wondered if they remained open post-blackout and were never able to be closed once venting became necessary.

[Loffy Muffin]

If you are interested in understanding what impact the presence of Mixed Oxide Fuel had, than get a copy of the ANS Technical Brief dated 03-25-2011 that was prepared by Michaele (Mikey) Brady Raap.

It clearly explains the impact MOX fuel had on the accident consequences at Fukushima Daiichi.

While the article defines a very tight (and miss leading) objective  to address, it totally misses the impacts of a failed MOX fuel cell that a reader might expect from the "American Nuclear Society".  Now, what would that be? 

Oh, here it is: Plutonium now detected in soil samples taken over a week ago.

At what point does Japan Prime Minster Fire these TEPCO clowns?  What does it take?  It looks like they wanted to quit and walk off the job two weeks ago, and their actions show conclusively they are no where near being up for the task at hand.  The are using unqualified personnel for dangerous clean up and wasting the efforts the work force that is volunteering blindly following a sense of patriotic duty.   

The PM should have accepted the resignation proposal from Fukushima NP and transitioned Emergency Response management to GE-Hitachi. Or Areva.  Or ten random guys at the airport. There is no indication T+2 weeks into this that their is any leadership, management, or central control in place.  What is the plan?  Answer, there is no plan.  You are looking at it.

A quick look under the hood of this TEPCO operation shows why:  a history of coverups, bribes, forged maintenance inspections, parts failure, deaths, rad releases.  And that is just what we know about with government officials and oversight in their back pocket.   

[Matthew B]

Do you remember where you saw that Japanese plants did not get the hardened vent mod to allow venting direct to the stack? I saw an recent interview with the NRC commissioner who said he didn't know if they had it.

I think it was the NEI; when I go back to the document it appears to have been modified due to the recent testimony.

There are many ways hydrogen can get into a Mark I secondary containment even if you are intentionally trying to send it up the stack - sustained high pressures in primary containment can force it through valve seats, leakage through HPCI/RCIC steamsides, operating RHR in steam condensing mode, etc. Also, to successfully vent primary containment to the stack, you must isolate the Standby Gas secondary containment suction dampers; normal position for those dampers is open, and I've wondered if they remained open post-blackout and were never able to be closed once venting became necessary.

Since you're far more familiar with these plants, how likely do you think it is for the hydrogen to back up into a sister unit?

[Nuclear Renaissance]

Since you're far more familiar with these plants, how likely do you think it is for the hydrogen to back up into a sister unit?

Well the more I think about it, the more plausible your theory that Unit 3 hydrogen migrated back down from the stack into Unit 4. It is a long way to go, but if the venting driving head was about 100 psig in Unit 3 primary containment, then at the base of the stack to was maybe 30ish pounds, which is probably enough to force some backward though Unit 4 Standby Gas (whose secondary containment suction dampers would have been in the normal open position). Over the course of several ventings, it could have pooled enough in the upper regions of the Unit 4 refuel floor until it reached deflagration (burn, not explode) levels. The assumption, though, would have to be that that Japanese plants do have the hardened vent mod, which would have allowed primary containment venting to the stack.

[chimmike]

Forgive me for being an outsider. This thread has really enlightened me on a lot of details.

But my question now is this:

How in God's name can they still with any confidence compare this disaster in any way to TMI? With the massive radiation release going on with Daiichi, likely primary containment leakage (which they still cannot confirm........why? too dangerous to send someone in? What about a robot?), radioactoive water escaping to the ocean via overflow releases (or whatever they're called), and likely major SFP issues? Shouldn't this be a 6 on the 7 level scale?

I think by this continuously being compared to TMI on the scale, they're blowing TMI way out of proportion, making TMI seem so much worse than it actually was.

I agree with Loffy Muffin, because as an outsider, just a normal joe, it looks like they have absolutely no plans, and the Gov't is just regurgitating whatever TEPCO tells them, which may or may not be correct, and is likely to be highly filtered and neutered vs. the truth. I agree the workers there are heroes, but their leadership appears to be plowing through the dark using telekinesis.

[Marlin]

Forgive me for being an outsider. This thread has really enlightened me on a lot of details.

But my question now is this:

How in God's name can they still with any confidence compare this disaster in any way to TMI? With the massive radiation release going on with Daiichi, likely primary containment leakage (which they still cannot confirm........why? too dangerous to send someone in? What about a robot?), radioactoive water escaping to the ocean via overflow releases (or whatever they're called), and likely major SFP issues? Shouldn't this be a 6 on the 7 level scale?

I think by this continuously being compared to TMI on the scale, they're blowing TMI way out of proportion, making TMI seem so much worse than it actually was.

I agree with Loffy Muffin, because as an outsider, just a normal joe, it looks like they have absolutely no plans, and the Gov't is just regurgitating whatever TEPCO tells them, which may or may not be correct, and is likely to be highly filtered and neutered vs. the truth. I agree the workers there are heroes, but their leadership appears to be plowing through the dark using telekinesis.

   To put this simply, they are responding to a disaster beyond the Safety Basis Design with a thousand year event, the fifth largest earthquake in recorded history. They are in a controlled chaos mode that does not lend itself well to updating upper management on every minute detail and I don't think they should their priority is the safety of the public right now as the plants are a loss. Communication is starting to flow but they just got lights back on in their control rooms this week so that is not to bad in my opinion.
   You are right this should not be compared to TMI which was purely an economic disaster for the utility alone. It is not close to Chernobyl which blew a large portion of its active core out the top of the building. That and the design of Chernobyl was substandard by western norms, that and the Russian bureaucracy fueled an initial plant condition with safety systems blocked for an experiment.
   Yes you are right the front line workers are heroes.

[hamsamich]

This Fuku things seems to be something in between TMI and Chern.  More units involved than either with Fuku, more radiation released to the environment than TMI, more physical damage to components that are supposed to protect the health and safety of the public than TMI, more damage to levels of containment.  No deaths attributed to acute radiation exposure yet....TMI had none, chern had plenty.  100 rem/hr due to airborne near the Fuku plant is another hard to swallow point put out by the media, I think they meant puddles of radioactive water were reading 100 rem/hr (1,000 millisieverts per hour reported).  Maybe they mean if you stuck your face right in the middle of the plume of the worst unit?  Until TEPCO puts out better reports and more of the mainstream media learns to interpret better, we are still in the who knows phase....

[chimmike]

Right Marlin, I agree with some points. Of course we don't get the whole story though the media so I try to take it with a grain of salt, but there needs to be a reliable, consistent line of reporting from the front-line guys to the corporate heads/government to allow the full situation to be understood. What I believe is happening is TEPCO is watering it down for the government rather than telling the whole truth. I believe TEPCO knew from the get-go that this was a terrible scenario and that radiation was escaping but wanted the Govt' to believe they had a handle on it.

I know this is definitely no chern. I've read a lot on Chern and it seems like that was just a snowball of ignorance, disbelief, and failure to follow procedures based on warnings. And the several people sent to check the reactor who reported it had exploded were consistently met with disbelief.....just unbelieveable that situation was.

However, TMI was minor, in my opinion, compared to Daiichi is now. We're getting Iodine isotopes reported on the east coast of the U.S., some 5,000 miles from Daiichi. I can't sit here as an outsider with a straight face and go "oh, this is no big deal to Japan, those workers have this under control."

The way I see it, they need to inject boron/concrete into those reactors and stop this whole mess now. I doubt they'll be able to safely get in there and remediate/disassemble those things in any safe manner to people or property. I know the plant is a total loss, that much was clear when they started using salt water.

Again, forgive me, but that is my view as an average joe.

[hamsamich]

need to cool the reactors.  covering it all with concrete would not help that cause until much later.  freshwater much better at this point to keep them from catching on fire at 2200F or more. gotta get rid of the decay heat first.

[Marlin]

The way I see it, they need to inject boron/concrete into those reactors and stop this whole mess now. I doubt they'll be able to safely get in there and remediate/disassemble those things in any safe manner to people or property. I know the plant is a total loss, that much was clear when they started using salt water.

   Then what do you do with the monolithic waste that needs to be monitored and controlled. If you followed Chernobyl you would know that they burrowed under the facility as well to contain it. The less you have to dig out and ship to a proper landfill or above ground repository the better. Beach front mausoleums does not sound like a good stable environment for this kind of "nuclear waste" here in the US it would be "greater than class C" waste which has no permanent disposal path at this time.

Again, forgive me, but that is my view as an average joe.

Nothing to forgive, you are much better informed than most "average Joe's" I speak with.