Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[M. Bachmeier]

Well, speaking about what happened early on, Unit 1 blew up immediately after venting. That might make operators reluctant to go ahead and vent Units 2 and 3. So pressure builds until Unit 2 and 3 explode. Unit 2 blows through the torus suppression pool without a lot of external damage to the building. Plutonium doesn't get on the ground that way. But Unit 3 was, as Ed Sullivan might have said, a "big, big, really big" explosion. My best analysis of the photos says it blew up and out of the south end of the top floor of Bldg. 3. If the source were from inside the primary containment and it didn't blow out of the torus pool, then it blew the drywell cap, came out the side of the primary containment, through the chute, and into the SFP.

That, to me, seems the most likely route to get Pu out, up, and back down on the ground.

Yes forensic inquiry, what precipitated these events, those are questions that are traditionaly asked afterward, but this seems to be a case where forensic investigation needs to be on par with events.

 

[jlduh]

Trench dimensions:
3x4x76 meters.
Source: http://www3.nhk.or.jp/daily/english/28_h37.html

3x4x76 = 912 m3.

Lets say 70% is full of water = 638 m3 of water. That is a lot of water...

I would like to learn:
1. Did it fill up from the Tsunami wave? Plausible.
2. When did last time inspect it - i.e. has it been dry after the Tsunami hit?
3. The article above talks about "a poodle of water" - which is VERY different from other stories of "filled to the brim".

Bottomline:
1. We don't know how much water is in the trenches
2. It would be good to learn how water rthere is
3. And if the trenches has been reported dry since the tsunami

and
4: Has these trenches been regularly checked for water seeping out of the containment?

The questions you ask are very legitimate. I have a hard time imagining that those trenches don't have been to some extent filled with seawater during the tsunami above them...

On the volumes of water in the trenches, if i look at this picture of the Tepco press conference, I see m3 written in the last column at the right side of the board, and if i sum up the volumes indicated for reactor 1 to 3, i end up with 13 300 m3 (3100 + 6000 + 4200)...
(click)
http://www.netimago.com/image_183582.html

This would be much more than your calculations.

As said before, a shame these conferences are not translated or transcrypted to english?

For Goldman Sachs asking employees to stay there, I think it's because anyway Goldman Sachs is more dangerous for human life than 3 wrecked reactors, so no real danger for those who are inside it's core...

 

[AtomicWombat]

http://www3.nhk.or.jp/daily/english/28_h28.html

"pumping in 16 tons of water every hour in #2, might cut down to the 7 tons that are evaporated every hour".

1. What happens to the 9 tons that doesn't evaporate?

The idea is to fill the reactor & keep it full, even if the water is boiling. The problem appears to be at least 2 reactors are leaking.

2. How much thermal energy does it take to evaporate 7 tons of cold water?

From the UCS site:

So that's 7ton*540Mcal/ton = 3780 Mcal
1 Calorie is 4.2 Joules, so 4.2*(J/Cal)3780 Mcal = 15876 MJ ~ 16 GJ

3. Where does all this steam go?

Either to the condenser (for the reactors - assuming it's working) or straight into the atmosphere (esp. for the spent fuel ponds).

 

[jlduh]

About the concerns for the pollution in the ocean, some basic infos:

1) it seems there is a North to South current that passes along the coast at Fukushima, so if pollution is massive it will probably move towards the south.

http://www.netimago.com/image_183571.html

2) then the current at a bigger scale is dominated by the Kuroshio
http://en.wikipedia.org/wiki/Kuroshio_Current

which then crosses the Atlantic.
http://www.netimago.com/image_183574.html
http://en.wikipedia.org/wiki/Ocean_current

If the pollution is really massive, can we anticipate that surfers on the west US coast will be much less sexy with lead swimming pants?

Or maybe we'll have a "great radioactivity patch" to compare with the "great garbage patch" already existing in the middle of Pacific Ocean:
As said previously, i think dilution in the ocean is a difficult task to predict (i don't even know if models exists similar to what exists for atmospheric regime, see the ZAMG simulation for example) .

But sediments along the Japanese coasts with local concentrations of contamination due to local currents are probably the worst to anticipate. But again not sure there are a lot of studies available concerning mecanisms of nuclear pollution in the ocean (maybe some related to the submarines?).

 

[Astronuc]

This may well be a naive reaction, but it seems to me that the obvious thing to do with the radioactively contaminated water in the turbine buildings is to pump it back into the reactors. Is there something wrong with that action? If/when they are able to re-establish core cooling, perhaps they could then work on dealing with the water contamination (salt, radioactive elements, etc) and leaks. But until then, why not reuse this water for the evaporative cooling?

Pump highly radioactive water to an area where it can be heated and release more radioactive delayed neutron precursors or accelerate gamma or Beta emitting dispersal?

Not a good idea.

Pumping contaminated water back to the site of the contamination is not good certainly. Eventually, whatever is leaking out becomes more contaminated, and that means increased dose rate and cumulative dose for those involved.

Assuming the fission has ceased, the delayed neutron precursors, the longest-lived being Br⁸⁷ (t_1/2 = ~55 s), are long decayed away.

I'm not sure where they plan to put the contaminated water. Perhaps back in the torus, if it has spare volume. If the contaminated water contains solid fission products, then this would suggest fuel washout, which then suggests some leak path from the primary system, e.g., feedwater system, the reactor water cleanup system, or possibly from somewhere in containment, from the lower levels of the containment, or containment sump and torus.

Ideally the contaminated water would be 'contained' in containment, but that does not appear to be the case, otherwise the contaminated water should be flowing in a closed system. However, with contaminated water in the turbine building, this would seem to be hampering efforts to re-establish a closed system.

Solutions of uranyl ions (e.g., uranyl nitrate hexahydrate) would normally be precipitated in a caustic solution, typically with ammonium hydroxide. The precipitate would be collected, dried and then calcined to an oxide powder. This may be an option, but it requires a special portable chemical process plant. Otherwise the solution has to be dewatered, perhaps by vacuum dehydration in a process similar to the production of freshwater from seawater, which leaves behind a more concentrated solution. The problem then is one of collecting the water - with submersible pumps or vacuum hoses. Given the radioactive contamination in the water, perhaps this operation requires remotely operated vehicles (ROVs).

If there is a leak in containment or the piping of the feedwater and attendant systems, then that has to found and stopped in order to reduce/mitigate further contamination.

I wonder if the boric acid solution is buffered. In PWRs, it is common to buffer with LiOH in western PWRs, and KOH in Russion VVERs. The pH in the coolant is kept near neutral ~7.0, to slightly basic up to about pH = 7.4. Acidic water increases the corrosion of stainless steel and nickel alloys.


FYI - [PDF] Mark I Containment Report
http://www.nei.org/filefolder/Report_-_BWR_Mark_I_Containment_03192011_2.pdf

 

[M. Bachmeier]

The window of opportunity to contribute toward effective analysis of the pre-conditions and short term resulting conditions is potentially small.

I wonder if this wonderfully large group of intellect would participate in revision of perceived indictments perceived and known toward solutions... These being in short supply.

 

[turbo]

I'd like to request that people PLEASE re-scale images to maybe 800 pixels or 1000 at the most (horizontally) before posting them. This is a fast-moving thread, and it is very hard to follow the discussion, follow links, etc, when you have to scroll back and forth to see the text. Large images force the forum window to expand to fit, and any text on the same page of posts bleed out of the window, necessitating the scrolling.

Please, just some common courtesy. Thanks.

 

[jlduh]

I'd like to request that people PLEASE re-scale images to maybe 800 pixels or 1000 at the most (horizontally)

You are right, sorry for the big image, i edited and replaced it by a vignette

 

[turbo]

You are right, sorry for the big image, i edited and replaced it by a vignette

Thank you very much! This page of posts is now easily manageable, and allows others to perhaps have two instance of a browser open in order to follow external links that may be overloaded and slow to load. Much appreciated!

 

[rhody]

Astronuc,

"Correct me if I am wrong, but there was no Plutonium in the SFP at Unit 4, right? "

Considering there is plutonium in the Reactor core of #3, and if you address TCups question (above), possibly in the SFP for Unit #4 as well, one would think because of the danger of contamination of that extremely long lived radioactive element (plutonium), that more urgency would be given to addressing the isolation/safe removal if possible from both sources. You said in an earlier post that the plutonium rods are diversely spread in the core, right ? If I had to do a cost/risk benefit analysis of the danger and had to choose spreading more short lived radioactive elements while being able to safely remove the longer lived ones, that course of action would seem logical, no ?

Rhody...

 

[Joe Neubarth]

Pumping contaminated water back to the site of the contamination is not good certainly. Eventually, whatever is leaking out becomes more contaminated, and that means increased dose rate and cumulative dose for those involved.

Assuming the fission has ceased, the delayed neutron precursors, the longest-lived being Br⁸⁷ (t_1/2 = ~55 s), are long decayed away.


FYI - [PDF] Mark I Containment Report
http://www.nei.org/filefolder/Report_-_BWR_Mark_I_Containment_03192011_2.pdf

I debated the delayed neutron precursor statement and then thought, "We do not know where all of the Plutonium and Uranium is." We know some is scattered outside the reactor, but there is a strong possibility that it is in the Turbine area, and if so may be splitting as we speak. How much, if any, of that that is from the core we do not know. But I suspect that the core has lost some of its fuel.

Hopefully some of the Uranium fuel is still in the core and if so, exposure to more neutrons is not a good thing as it just makes things dirtier and dirtier. That will just yield more delayed neutron precursors and even more radiation. Nobody caught on to the fact that if the Boron in the control rods was probably totally dissolved in reactor water if we had a full meltdown and that water was being replaced (Not always with borated water), the net total volume of boron in the reactor had probably greatly decreased, and may have resulted in a power transient type reaction which could have taken the uranium lava out from the bottom of all containment. I suspect that has happened in part or in whole.

 

[AtomicWombat]

I would like to learn:
1. Did it fill up from the Tsunami wave? Plausible.
2. When did last time inspect it - i.e. has it been dry after the Tsunami hit?
3. The article above talks about "a poodle of water" - which is VERY different from other stories of "filled to the brim".
4: Has these trenches been regularly checked for water seeping out of the containment?

This NHK report (with an expert interview) was very clear that it was just centimeters from the brim and still rising.
http://www.youtube.com/watch?v=G3QJ8mxZOxA"

At least some of the water must come from the turbine building - for >1000 mSv/hr I'm tempted to say most of it. Tsunami water is generally not radioactive. If they did a radioisotope analysis (as done for the water in the turbine buildings) it would be very clear how much of the water is from the turbine building.

 

[AtomicWombat]

Guys. If radioactive water keeps leaking and outside to the Pacific Ocean. How many miles off shore will the danger remain? I only eat fish and concerned about this.

This can only really be answered by sophisticated modelling followed by monitoring.

 

[AtomicWombat]

Astronuc,

"Correct me if I am wrong, but there was no Plutonium in the SFP at Unit 4, right? "
Rhody...

Yes I'm not Astronuc, but the short answer there is plutonium in all spent nuclear fuel at the site, including that partially "burned" in reactors 1 & 2.

http://www.fas.org/nuke/intro/nuke/plutonium.htm"

"A useful rule of thumb for gauging the proliferation potential of any given reactor is that 1 megawatt-day (thermal energy release, not electricity output) of operation produces 1 gram of plutonium in any reactor using 20-percent or lower enriched uranium; consequently, a 100 MW(t) reactor produces 100 grams of plutonium per day and could produce roughly enough plutonium for one weapon every 2 months. Light-water power reactors make fewer plutonium nuclei per uranium fission than graphite-moderated production reactors. "

 

[turbo]

Astronuc,

"Correct me if I am wrong, but there was no Plutonium in the SFP at Unit 4, right? "

Considering there is plutonium in the Reactor core of #3, and if you address TCups question (above), possibly in the SFP for Unit #4 as well, one would think because of the danger of contamination of that extremely long lived radioactive element (plutonium), that more urgency would be given to addressing the isolation/safe removal if possible from both sources. You said in an earlier post that the plutonium rods are diversely spread in the core, right ? If I had to do a cost/risk benefit analysis of the danger and had to choose spreading more short lived radioactive elements while being able to safely remove the longer lived ones, that course of action would seem logical, no ?

Rhody...

As I understand it, not all the uranium in the fuel rods is 235, though the fuel is enriched to enhance that. Lots will be U 238, which by absorption of neutrons will convert to plutonium 239. So any fuel rods that have seen a lot of use should have a decent fraction of plutonium. So dispersed fuel from the spent fuel pools could elevate the levels of plutonium detected outside - not just the MOX fuel used in #3.

Astro and others, if I am way off base, please say so.

 

[rhody]

Yes I'm not Astronuc, but the short answer there is plutonium in all spent nuclear fuel at the site, including that partially "burned" in reactors 1 & 2.

http://www.fas.org/nuke/intro/nuke/plutonium.htm"

"A useful rule of thumb for gauging the proliferation potential of any given reactor is that 1 megawatt-day (thermal energy release, not electricity output) of operation produces 1 gram of plutonium in any reactor using 20-percent or lower enriched uranium; consequently, a 100 MW(t) reactor produces 100 grams of plutonium per day and could produce roughly enough plutonium for one weapon every 2 months. Light-water power reactors make fewer plutonium nuclei per uranium fission than graphite-moderated production reactors. "

Thanks AW,

I understand, a lot of toxic fuel to isolate and somehow safely remove... I wish them well in the herculean effort that will be required. Thanks Turbo, you and AW pretty much nailed it.

Rhody...

 

[AtomicWombat]

In part, from above reference:

"Dr. Sekimura of Tokyo university pointed out the possibility of damage to the fuel in the spent fuel pool of unit-3 since it would appear that the heavy crane have dropped into the fuel pool in this movie. (05:40, March 28)"

I wonder if this makes sense:

1) vertical shaft
2) SFP3
3) Fuel rod handling equipment in SFP3
4) Region of the transfer chute and gate

TCups,
Do you realize that is a view from the north - the opposite side from which you were previously suggesting the SFP was on.

 

[TCups]

TCups,
Do you realize that is a view from the north - the opposite side from which you were previously suggesting the SFP was on.

CORRECTION

[STRIKE]It is a view from the north, looking into the south end of Unit 3, I believe. [/STRIKE] The SFP's are in the southeast corners of Units 3, 4. The original screenshot I annotated WAS NOT the SFP. It was a shot of the equipment pool on the north end of Bldg 3. The original post has been corrected. Sorry for the error.

 

[razzz]

From
http://en.wikipedia.org/wiki/Boiling_water_reactor

Size

"...A modern BWR fuel assembly comprises 74 to 100 fuel rods, and there are up to approximately 800 assemblies in a reactor core, holding up to approximately 140 tons[vague] of uranium. The number of fuel assemblies in a specific reactor is based on considerations of desired reactor power output, reactor core size and reactor power density..."

It's a starting point since some of the reactors are first generation, may not be loaded with such large amounts.. No wonder no one wants to talk about it. Germany has the right idea, decommission any current operating BWRs.

Seems to me, in a Murphy's Law event, with the amounts of fuels involved between 3 crippled reactors and 4 spent pools, every combination and variation of a meltdown/partial meltdown is happening.

What's the worst case scenario fix, vaporized the whole complex with a nuke? Or just post a no swimming sign in the Pacific Ocean and tell the Japanese that they can check out but they can never leave. If not, time will be spent for the next couple of decades robotically cleaning up and that is after the situation stabilizes because of the known and unknown (like a +8.0 Earth movement with accompanied sloshing).

I'm sure the think-tanks discussed all possibilities and will concluded by using percentages. If the DOD hasn't been tracking plumes and taking hi-res pics with sensor readings, they should be de-funded.

 

[AtomicWombat]

It is a view from the north, looking into the south end of Unit 3, I believe. The SFP's are in the southeast corners of Units 3, 4.

I personally can't say with any confidence where the SFPs are in any reactor building, but I'm fairly confident the layered structure beneath the fallen gantry crane beam is the northern external wall of the primary containment. Indeed the smoke appears to rise through the broken roof frame work very close to the northern edge of what's left.

I don't know how to do thumbs so I won't attempt to repost your image.

 

[TCups]

TCups,
Do you realize that is a view from the north - the opposite side from which you were previously suggesting the SFP was on.

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. () The pool shown would have to be the equipment pool, not the SFP. I don't know if the equipment pool has a transfer chute and gate.

Post #1760 has been edited with the correction and the annotated photo I first posted there deleted.

 

[RealWing]

I believe we will eventually find that the diesel generator problem originated with the fuel supply. The fuel tanks are outside of the buildings on a concrete pad separate from the building itself. Five minutes of earthquake shaking independent of the building, with fuel sloshing and adding to the forces on the tank/foundation, would stress the fuel supply lines and connections. If the break happened low enough to draw in water it would result in damage to filters, injector pumps and injectors that would consume more time than the golden 8 hours .

A good summary, but I'll offer one correction concerning EDG fuel supplies. Seismically qualified emergency diesel power supplies means that not only is the DG qualified, but so is the building, all piping and electrical equipment etc in the building, all cabling routes into the plant - but also the outdoor fuel supply tanks and all piping and intrumentation needed post seimic event. All of this should have survived the quake.

Now the tsunami is a different issue. Some possible failure modes are:
- the water wave moved the outdoor tanks and sheared off the fuel lines.
- water entered the EDG buildings and damaged some of the equipment - most likely electrical.
The plant was clearly designed for a lower wave height, so I would expect that the designers did not make the buildings watertight.

 

[Reno Deano]

This may well be a naive reaction, but it seems to me that the obvious thing to do with the radioactively contaminated water in the turbine buildings is to pump it back into the reactors. Is there something wrong with that action? If/when they are able to re-establish core cooling, perhaps they could then work on dealing with the water contamination (salt, radioactive elements, etc) and leaks. But until then, why not reuse this water for the evaporative cooling?

Nice idea, but the reactors are now filled (level TEPCO wishes). Pumping the water back would mean removing water from the vessel (remember previous post: do not want the reactor vessel to go solid with water!), and putting it where?

 

[AtomicWombat]

What's the worst case scenario fix, vaporized the whole complex with a nuke?

That is the worst possible "solution". One of the best ways to increase the radiological impact of an atomic bomb is to use it against a nuclear plant, as nuclear plants generally have many times as much radioactive material than nuclear bombs. The radiation doesn't just disappear it turns into dust and vapour and then blows over the nearby landscape.

Or just post a no swimming sign in the Pacific Ocean...

If we could actually dissolve the whole thing in the Pacific Ocean people would hardly notice. The Pacific is so vast that the additional radioactivity would be tiny.

If not, time will be spent for the next couple of decades robotically cleaning up and that is after the situation stabilizes...

Yup, that's my guess. That's essentially what happened after TMI & Chernobyl, although with less emphasis on robots.

 

[Reno Deano]

How do you explain this?

Goldman Sachs Employees Told Not to Leave Japan
http://www.cnbc.com/id/42304574

Simple: Goldman Sachs is removing their gold in sacks to prevent neutron activation of it. The neutron beam story really scared them.

 

[AtomicWombat]

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. ()

That's OK TCups. This is all pretty much a scientific exercise. We each propose hypotheses, offer evidence and then shoot each other down.

Gee I wish I had your screen-capture and picture posting skills. Mine are rudimentary. If I can't copy links I'm lost.

 

[M. Bachmeier]

so we are talking about the rods in the pool

M. Bachmeier,
Tepco did not provide data for the first 12h or so.. Mitsuhiko Tanaka pointed just like you did that the first 12h are crucial to understand what could have happen.. from the initial data he does figure a few thing
Reactor 1 Core vessel at t+12 is at 0.80Mpa donw from 7MPa , First reading of Containment Vessel is at 0.8Mpa (twice the design spec) up from 0.1MPA normal operating pressure.

That's kind of like making my point. Is there nobody on site (at the time) who could backtrack the data toward possible scenarios given their knowledge of the situation at the time. Besides, I'll bet my bottom dollar there was more to the initial data then is publicly known.

 

[Joe Neubarth]

As I understand it, not all the uranium in the fuel rods is 235, though the fuel is enriched to enhance that. Lots will be U 238, which by absorption of neutrons will convert to plutonium 239. So any fuel rods that have seen a lot of use should have a decent fraction of plutonium. So dispersed fuel from the spent fuel pools could elevate the levels of plutonium detected outside - not just the MOX fuel used in #3.

Astro and others, if I am way off base, please say so.

Five percent enrichment with 235.

 

[TCups]

That's OK TCups. This is all pretty much a scientific exercise. We each propose hypotheses, offer evidence and then shoot each other down.

Gee I wish I had your screen-capture and picture posting skills. Mine are rudimentary. If I can't copy links I'm lost.

Get yourself a Mac and it's very easy [Cmd]+ [Shift] +[4] gives a "+" cursor. Drag it over the screen and it takes a PNG snapshot of whatever is on the screen at that resolution. Then just add it as an attachment or drag the screenshot into Preview or Photoshop to annotate. I use Photoshop if I need to reset contrast, level or sharpen.

Only takes a few seconds. For example . . .

 

[AntonL]

here some basic facts to the cooling problem and amount of fuel on site

Unit 1
design 460 MWelect 1380MWtherm
400 Fuel elements in core and 292 in SFP
rest heat day 17 - 2.66MW reactor and about 60kW for pool

Unit 2
design 784 MWelect 2381MWtherm
548 Fuel elements in core and 587 in SFP
rest heat day 17 - 4.59MW reactor and about 400kW for pool

Unit 3
design 784 MWelect 2381MWtherm
548 Fuel elements in core (6% MOX since August 2010) and 541 in SFP (?% MOX)
rest heat day 17 - 4.59MW reactor and about 200kW for pool

Unit 4
design 784 MWelect 2381MWtherm
0 Fuel elements in core and 1331spent +200unused in SFP
rest heat day 17 - 0MW reactor and about 2000kW for pool

Total 14.5MW of cooling required

rest heat assuming 100% load at time of accident
in about 2 months the rest heat would be 50% of above
1MW will boil away 1.41 m3/h of water at temperature of 30 degree

Total 14.5MW of cooling required that is 20.5 m3/hour without overflow and spillage--------------------------------------
under control

Unit 5
design 784 MWelect 2381MWtherm
548 Fuel elements in core and 946 in SFP
rest heat day 17 - 4.59MW reactor and about 700kW for pool

Unit 6
design 1100 MWelect 3293MWtherm
764 Fuel elements in core and 876 in SFP
rest heat day 17 - 6.35MW reactor and about 600kW for pool

 

[AntonL]

Regarding the MOX fuel, I doubt that there is any in the SFP of reactor 3.

Thus any Pu measurements indicate a leakage from unit 3 reactor is this a correct assumption?

Third Japanese reactor to load MOX
10 August 2010
Tokyo Electric Power Company's (Tepco's) Fukushima I unit 3 is set to become the third Japanese nuclear reactor to load mixed oxide (MOX) fuel after receiving approval from the governor of Fukushima Prefecture, Yukei Sato. The unit follows Kyushu Electric's Genkai 3, which started using MOX fuel in November 2009, and Shikoku's Ikata 3, which was loaded with some MOX fuel in March 2010. According to the Denki Shimbun, the 760 MWe boiling water reactor will be loaded with MOX fuel by 21 August and the unit will restart in late September. Japan's Nuclear and Industrial Safety Agency has so far approved the use of MOX fuel in ten reactors, but utilities must also secure approval from prefectural governments before they can go ahead and use the fuel, which contains plutonium recovered from spent nuclear fuel.

 

[ailog]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

 

[M. Bachmeier]

Has anyone looked at the potential leaks from the mounts of the dry-well caps 1-3?

I'm sure I've come across more than one reference to effective seating of the cap on older Mark I reactors.

Without guile, is this the primary leak of contaminants?

 

[Joe Neubarth]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

1.Once cool enough a massive quantity of water can keep the Reactor Fuel from heating up. The question is where is it?

2. Pressure?

3. Until we find out where the fuel is, Boron in ample quantities to meet water standards is necessary. The control rods with most of the boron in them may still be standing tall. Just because the Zirconium and the Uranium flowed down to the bottom of the reactor does not mean the Control rods did. If they did melt in conjunction with the reactor melt down, the Boron would have dissolved in solution. As they were pumping sea water in by the ton, they probably seriously diluted the amount of boron in the reactor even though they are said to have injected boron at the end of the sea water injection. The sea water injection by itself could have led to limited criticality and reheating of the forming Uranium Lava sufficiently to burn through the bottom of the reactor vessel. I suspect that they made a bad situation far worse. Now that the water has accumulated in many diverse places it has a dilute solution of boron in it, but we do not know for certain where the Uranium fuel is.

 

[razzz]

Press Release (Mar 29,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 9:00 am March 29th)[No update from the last release issued at 9:00 pm, March 28th]

Unit Status
1 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
2 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
3 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
4 · Reactor cold shutdown, stable water level, offsite power is
available.
· No reactor coolant is leaked to the reactor containment vessel.
· Maintain average water temperature below 100°C in the Pressure
Suppression Chamber.
Other N.A.

...Have a nice day...

 

[AntonL]

IAEA presentations available here http://www.slideshare.net/iaea/

 

[AntonL]

@AtomicWombat

I stand corrected, sir. The detail picture originally provided as a screenshot and then annotated by me to show what I thought was the shaft, SFP, and something in the SFP is apparently WRONG. The screenshot I annotated matches the north end of the floor of Bldg 3, not the south end, so it cannot be as I annotated it. Sorry for the error. () The pool shown would have to be the equipment pool, not the SFP. I don't know if the equipment pool has a transfer chute and gate.

Post #1760 has been edited with the correction and the annotated photo I first posted there deleted.

https://www.physicsforums.com/attachment.php?attachmentid=33668&d=1301364476

As the SFP is on the south side of the reactor, the steam escaping on the north side (follow link above) could indicate that the containment is breached and steam is not from a boiling SFP pool.

 

[AntonL]

[URL]http://www.asahi.com/national/update/0329/images/TKY201103290240.jpg[/URL]

[URL]http://www.asahi.com/national/update/0329/images/TKY201103290255.jpg[/URL]

The plan is to pump water in outside tunnel/trench into suppression water storage tanks marked by 2 blue dots south of unit 4. Total 6800m3 storage is available in those two tanks but 2800m3 are already stored - so 4000m3 can be pumped from the tunnel/trenches into those tanks.

The table list the maximum volume of the tunnel/trenches before overflowing, but we can see that they are about to overflow by the levels given.

 

[shogun338]

Has anyone looked at the potential leaks from the mounts of the dry-well caps 1-3?

I'm sure I've come across more than one reference to effective seating of the cap on older Mark I reactors.

Without guile, is this the primary leak of contaminants?

This is a good link about the seal that may be leaking a lot of this water around the area. http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at This happened at plant Hatch in Georgia back in 1986 and they lost over 140000 gallons of water from the spent fuel pool . Don't trust TEPCO to tell the truth because when this happened at Hatch they told everyone that only 5000 gallons leaked. I live very close to Plant Hatch and fish around it all the time on the Altamaha River .

 

[shogun338]

I have followed this thread and the situation in Japan but am uncertain of what's happening currently. Here are some GENERAL observations and some questions. Please comment to help my understanding.

1. There is presently no coolant circulation whatsoever in any of the reactors 1 thru 4? The rush to get electrical power back on was to no avail because coolant pumps/piping and electrical equipment and controls were damaged beyond repair. Which means that if the emerg. generators had survived they most probably wouldn't have mattered (wrt circulating coolant).

2. Currently the affected reactors are filled with seawater? If the seawater is not circulated and cooled somehow, how does this help the reactor core? Just distributes the core heat? Steam is being made and periodically vented to reduce pressure?

3. If boron is a good moderator, would pumping a slurry of boron into the reactors help?

USA has sent boron to Japan to pump into the reactors . Other countries are also sending it to Japan . http://www.liveleak.com/view?i=d35_1300513133

 

[Soafcom]

Here are a few more images of Reactor 3 from 2011-03-16:

 

[|Fred]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

ps: http://www.ustwrap.info/show/iwakamiyasumi
tepco Press conference just started

 

[AntonL]

notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?[/url]
tepco Press conference just started

If you check all available photos and videos you will see that the fuel loading tunnel to the west of the building is also destroyed. Unit 4 was under maintenance so fire/blast doors, hatches etc would be open that in units 1-3 would have been shut tightly allowing the blast to propagate from roof to basement as is evident in the visual material

 

[shogun338]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

ps: http://www.ustwrap.info/show/iwakamiyasumi
tepco Press conference just started

When reactor #3 exploded it caused most of this damage to unit 4 from the reports I have read . Here is a link to the very large explosion at reactor #3 . Reactor #3 is also the reactor that was loaded with the MOX fuel .http://ireport.cnn.com/docs/DOC-573617

 

[AtomicWombat]

This is a picture of unit 4 showing S/W wall and S/E wall
in Green overlay the operating Floor, in blue the alleged Spebt Fuel Pull
In yellow overlay the floor bellow the operating floor, notice that on this unit 4 the blast seems to have occurred on that yellow floor as well. how do we make sens of that ?

Hi Fred,
This is the southern wall of this reactor building. There is an almost identical hole in the northern wall (see my attachment) that has what looked to me like a discharge of corium lava. It may be just melted insulation. I am still unsure. Based on the position of the fuel crane (northern wall), it seems that this melted mass is unlikely to be corium.

I can explain the holes in the opposing sides assuming they are adjacent to the equipment pool (on one side) and the SFP on the other. Hydrogen would accumulate over the SFP. Once it reached the explosion limit the explosion would be strongest there, presumably strong enough to blow out both the SFP containment and the exterior wall.

Reactor diagrams also show that adjacent to the equipment pool the exterior wall is the only barrier to the outside environment. So this would be a weak point.

I find it difficult to explain why so many panels below the operating floor on the east and west side also blew out, especially since hydrogen is a light gas and would not tend to settle deep in the building..

 

[Emreth]

When reactor #3 exploded it caused most of this damage to unit 4 from the reports I have read . Here is a link to the very large explosion at reactor #3 . Reactor #3 is also the reactor that was loaded with the MOX fuel .http://ireport.cnn.com/docs/DOC-573617

We've been over this here, there are images after explosion at unit 3 which shows no damage on unit 4.

 

[AtomicWombat]

Unit 4 was under maintenance so fire/blast doors, hatches etc would be open that in units 1-3 would have been shut tightly allowing the blast to propagate from roof to basement as is evident in the visual material

Seriously? I had no idea these procedures were in place in reactors. It's like a warship or submarine.

 

[jensjakob]

Areva sends 2 experts to Fukushima:
http://english.kyodonews.jp/news/2011/03/81681.html

 

[shogun338]

We've been over this here, there are images after explosion at unit 3 which shows no damage on unit 4.

Why would it explode if it was in shut down mode ? Where is the link to the pics and the explosion of #4 ? I can't find them .

 

[Emreth]

Why would it explode if it was in shut down mode ? Where is the link to the pics and the explosion of #4 ? I can't find them .

This is the image after explosion #3 before #4. I don't think we have an explosion video for #4. #4 had fresh fuel in SFP.
https://www.physicsforums.com/showpost.php?p=3197547&postcount=539

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichiov_march14_2011_dg.jpg