Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[doc_u]

The four-reactor Fukushima II Daini plant was just 7 miles due south of the Fukushima I Daiichi plant. It was on the coast just like the Daiichi plant, was hit by the same earthquake and Tsunami, and to my knowledge is of similar design.

Why was it not as badly affected?

Wikipedia is our friend here:

Fukushima Daini (Daini means second or two)

Unit	First criticality     Reactor    Architecture	Construction
1	31/07/1981            Toshiba	 Toshiba	Kajima
2	23/06/1983	      Hitachi	 Hitachi	Kajima
3	14/12/1984	      Toshiba	 Toshiba	Kajima
4	17/12/1986	      Hitachi	 Hitachi	Shimizu Takenaka

So, it appears to be somewhat dissimilar to the first Fukushima plant, and obviously built much later, brought online AFTER TMI, so perhaps some lessons learned from that...

The real story for me (and that the media appears not to care about) is that out of the very large number of NPPs in Japan, we are really only facing major issues with 4 reactors at one plant.

Show THIS graphic, news people:

-doc

 

[TCups]

Those IR images are interesting. Why are there hotspots on the ground between 3 & 4? What are the cause of those hotspots? Very interesting.

Where? I see heat signatures from Unit 3 and 4, but not on the ground.

 

[Maxion]

Nuclear PR is familiar with the phrase 'freak accident', Daini (= Plant 2 in Japanese) experienced freak luck.

Seen that slowed-down video footage from the helicopter over Daiichi? Early on you see tarmac ripped like paper by the earthquake. A metre away and it's still intact. Earthquake causes local surface damage over a great many locations. Hope this unscientific explanation helps.

Also, the tsunami did not destroy the generators at Daiini and they got offsite power back quite quickly.

 

[jensjakob]

Where? I see heat signatures from Unit 3 and 4, but not on the ground.

Picture in post 721, I interpret the green areas (on the roofs?) as hotspots too

 

[jensjakob]

Very intersting.

Here we see no temperatures for SFP, but 5&6 are (in my interpretation) less critical than 1+2+3+4.
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300544332P.pdf

Then in this newsclip,
http://www3.nhk.or.jp/daily/english/20_33.html
we read "Water temp at 2 reactors below boiling point" - and the article covers 5+6.

I do NOT like the implications of these 2 items...

What are the temp at SPF 1+2+3+4?

My problem is that I begin to think that the information from JAIF is intended to be enough to keep people from asking why info isn't released - but at the same time the information is cleverly designed to omit the critical parts...

I would also still VERY much like to see radiation readings ABOVE the reactors. On ground level the buldiing shields a lot of the radiation, so the numbers around the site does not show the actual levels of radiation... :-(

 

[PietKuip]

Picture in post 721, I interpret the green areas (on the roofs?) as hotspots too

The green spots in the second image are patches of surface that are cooler (or have lower IR emissivity) than the rest of the roof.

 

[jensjakob]

The green spots in the second image are patches of surface that are cooler (or have lower IR emissivity) than the rest of the roof.

Apologies for misinterpretating. Sorry!

 

[TCups]

Let's say warm spots, comparatively. And I believe them to be on roofs. Which asks the question why there aren't corresponding warms spots on the ground in a symmetric distribution. Don't know what if any clean up has been done. Blast debris on the ground would cool more quickly than those on the roofs, perhaps.

If the color IR image scale is such that white is displayed at temps of only -- what was it? -- 128ºC, then these wouldn't seem incredibly hot. Remember, though, that thermal images can be windowed and leveled to make most everything look hot or cold. The colors are arbitrarily assigned and the temperature differences between colors can be very great or very small. We don't know the WW/WL or temp scales of these are.

It would be interesting to see the relative temps of the debris field and the square-looking thing on the roof that the helicopter fly over was looking at carefully -- to the northwest, in one of the earlier posts.

 

[jensjakob]

Also interesting to see that no 1 has hotspots at each side of the concreteplug, just where those gates are between the pools, and the drywell head...

 

[bondboy]

Great question! I want to know the readings above and within the reactors. I pulled this from NHK. My follow up question is what are the other 4 materials found? They keep quoting Iodine131 levels but never mention the other materials made by fission.
Anyone care to venture a guess as to what they could have found?

http://www3.nhk.or.jp/daily/english/21_22.html
5 radioactive materials detected
Tokyo Electric Power Company says some of the nuclear fuel at the Fukushima Daiichi nuclear power plant has apparently been damaged, as higher levels of radioactive materials have been detected in the vicinity.

The utility on Monday released the results of a radiation survey carried out at the plant on Saturday.

Officials detected in the air 5 radioactive materials that are generated by nuclear fission.

The level of iodine 131 was 5.9 milibecquerels per cubic centimeter. That's about 6 times the permissible level for workers without protective masks.

The density of the other substances was also higher than usual, but within safety standards.

The utility says the radiation is likely to have come from the damaged reactors, and added that it will check radiation levels daily.

The company also says it has no plan to halt efforts to restore power and pour water into reactors, as these activities pose no risk to workers as long as they wear protective masks.
Monday, March 21, 2011 19:35 +0900 (JST)

 

[jensjakob]

A whole lot of NPP diagrams and layouts - though no BWR as far as I can see:
http://econtent.unm.edu/cdm4/browse.php?CISOROOT=/nuceng

 

[TCups]

The green spots in the second image are patches of surface that are cooler (or have lower IR emissivity) than the rest of the roof.

The green is typically warmer than blue. By comparison, for example, the roofs of the turbine buildings in the lower part of the image (foreground) are a nice green color. The inside of the buildings is still warmer than the outside ground temp. I seem to recall it is winter there. Here is a lovely grayscale photo of myself converted to color with a a typical thermal image look up scale. Do I have "hot" hair?

 

[|Fred]

Anyone care to venture a guess as to what they could have found?

From what I read this morning (GMT) they found 3 iodine isotopes and 2 cesium isotopes.

I do not recall all the numbers but it wrote the most significant one
Iodine131 up to 1500 Bq/l
Cesium137 up to 18 Bq/l

 

[TCups]

Also interesting to see that no 1 has hotspots at each side of the concreteplug, just where those gates are between the pools, and the drywell head...

Perhaps the gates are solid steel and have greater thermal conductivity than concrete? Don't know what it means for sure.

 

[Reno Deano]

Great question! I want to know the readings above and within the reactors. I pulled this from NHK. My follow up question is what are the other 4 materials found? They keep quoting Iodine131 levels but never mention the other materials made by fission.
Anyone care to venture a guess as to what they could have found?

http://www3.nhk.or.jp/daily/english/21_22.html
5 radioactive materials detected
Tokyo Electric Power Company says some of the nuclear fuel at the Fukushima Daiichi nuclear power plant has apparently been damaged, as higher levels of radioactive materials have been detected in the vicinity.

The utility on Monday released the results of a radiation survey carried out at the plant on Saturday.

Officials detected in the air 5 radioactive materials that are generated by nuclear fission.

The level of iodine 131 was 5.9 milibecquerels per cubic centimeter. That's about 6 times the permissible level for workers without protective masks.

The density of the other substances was also higher than usual, but within safety standards.

The utility says the radiation is likely to have come from the damaged reactors, and added that it will check radiation levels daily.

The company also says it has no plan to halt efforts to restore power and pour water into reactors, as these activities pose no risk to workers as long as they wear protective masks.
Monday, March 21, 2011 19:35 +0900 (JST)

One note: 5.9 milliBq/cm3 is not over any limit. Even if it was 5.9KBq/cm3 it would be be the Occupational DAC (10 CFR 20, Appendix B) limit of 7.4E3 Bq/cm3. Hope my conversions are correct!

 

[jensjakob]

Fukushima Daiichi nuclear power plant near the sea damaged by the earthquake east, found that the concentration of radioactive material falls up to 126 times the safety standards, announced at a press conference early Tuesday TEPCO 22.

According to TEPCO, near the outlet 21 at 2:30 pm were examined with 0.5 liters of water collected, the criteria established by the Nuclear Reactor Regulation Law is 126.7 times the iodine 131 was detected. This water year, and continue to take every day, the annual limit public exposure to radiation falls on 126.7-fold (nuked) will be. Cesium 134 is a standard 24.8-fold addition, the cesium-137 detected 16.5-fold

http://translate.google.com/translate?sl=ja&tl=en&js=n&prev=_t&hl=da&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.asahi.com%2Fnational%2Fupdate%2F0322%2FTKY201103210384.html

 

[PietKuip]

One note: 5.9 milliBq/cm3 is not over any limit. Even if it was 5.9KBq/cm3 it would be be the Occupational DAC (10 CFR 20, Appendix B) limit of 7.4E3 Bq/cm3. Hope my conversions are correct!

No, those would be horrible levels. http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/appb/Iodine-131.html" says that the inhalation DAC for I-131 is 2E-8 microcurie per ml, which is 0.74 milliBq/cm3.

 

[HansHooligan]

Hi. In this video at about 4:19 in my opinion has fuel rods
Look at the shape of those, looks just like these

What you think?

edit: It seems this video was here already. Just missed it because screen caps are not visible anymore due to exceeded bandwith.. :|

 

[Maxion]

Hi. In this video at about 4:19 in my opinion has fuel rods
Look at the shape of those, looks just like these

What you think?

edit: It seems this video was here already. Just missed it because screen caps are not visible anymore due to exceeded bandwith.. :|

When looking at the video you can quite clearly see the so called fuel rods extending out from concrete slabs at steady intervals. That is rebar, not fuel rods.

Also if you look at the IR shots from today you see no heat signature from where these so called fuel rods are. If these were real fuel rods they would be warmer than ambient.

 

[HansHooligan]

I missed that "at steady intervals", seems more like "just a bunch of sticks".
I don't think that those thermal images are accurate enough to show 10mm thick fuel rods unless those are at really high temperature.

Just my 2 cents.

 

[Maxion]

I missed that "at steady intervals", seems more like "just a bunch of sticks".
I don't think that those thermal images are accurate enough to show 10mm thick fuel rods unless those are at really high temperature.

Just my 2 cents.

With THAT many fuel rods close together they would show. The only "proof" there is of those being fuel rods is a layman's opinion after looking at some shaky, low resolution and blurry footage. Also real fuel rods are bunched together in bundles. If they were fuel rods, how could all of the fuel rods be completely detached from their bundles and still staying that intact as in the video? And have no of the bundle parts attached to them?

And on top of that we also have the IR images showing NO heat from that area. Keep in mind thermal imaging resolution does not work the same way as resolution in a regular camera. Heat coming from a 1cm thick rod will not require a 1cm/pixel resolution of the camera since heat radiates and heats up stuff around the object producing heat.

IF they are fuel rods I will eat my hat.

 

[TCups]

When looking at the video you can quite clearly see the so called fuel rods extending out from concrete slabs at steady intervals. That is rebar, not fuel rods.

Also if you look at the IR shots from today you see no heat signature from where these so called fuel rods are. If these were real fuel rods they would be warmer than ambient.

I don't know if these are fuel rods or some other rod. I don't know the exact relationship of the location of the "rods" to the heat signatures seen on the IR photos posted today. I do know that after the explosion, in this pile of rubble, in this field of view, it would be somewhat reassuring to see even one bent piece of a rod. Absent that, one possible conclusion is that these rods seem to be much more rigid than the bent rebar seen in other areas. If any of these were once embedded in concrete, I can see no conclusive evidence of it on this shot.

I also believe that the green structure in the lower right may be part of the fuel rod handling equipment. If so, then it might support the notion that these are at least somewhere near the location of the SFP.

I also believe the reports that some high level radioactive debris are on the ground and that they have sufficient activity, if not obvious heat, to warrant the workers using dozer blades attached to military tanks to clear the high-level radioactive debris to permit safer access to work on units 3 & 4. There aren't that many different possibilities of sources for high-level radioactive debris on the ground that I can think of.

I suspect I can no more convince anyone these are fuel rods than anyone can convince me that after the explosion, all the fuel rods are still in the SFP and that they survived the blast, unscathed.

 

[aamrwc]

The JPG picture T-cup shows doesn't look like re bar to me. RE bar would bend. There are other pictures of bend re bar in other clips. These sure look like a pile of fuel rods like in #757. None of it is bent and I don't see any attached concrete

 

[AtomicWombat]

@Wombat
Well if I'm not mistaken in your calculation you assume that the radiation level measure taken at x meters are "induce" from the radiation source hence your reverse invert square law calculation.

In my opinion you are likely making a false assumption / interpretation : The radiation source are more likely the volatile isotope in the air , at least for the most part.


ps: to make my self more understandable your calculation would be right if let say you had a pile of radioactive isotope outside your windows, you were in your house and wanted to know how radioactive this pile was taking a measurement from a distance. But what we have here is a window leaking and wind blowing some of the stuff to the inside..

Thanks for your comment Fred,

The origin of this line of reasoning was the the possibility that the lava-like discharge from the hole in the north side of reactor 4 is corium. Corium would emit gamma rays.

See:
https://www.physicsforums.com/showpost.php?p=3193343&postcount=331
https://www.physicsforums.com/showpost.php?p=3194084&postcount=381
https://www.physicsforums.com/showpost.php?p=3195114&postcount=416

I have no way of ruling out lofted radio-nucleotides as the source of the radiation.

 

[TCups]

Here are a few questions for those more sure than me to ponder:

What is a reasonable estimate of the mean age of spent fuel rods stored in a SFP after removal from the reactor? Is it possible that after many months or years in the SFP the rods might have exhausted the residual heat to level that they would not glow and might be lost in the background heat signature coming from the ruins of Unit 3?

What might become of the contents of one of those casks coming off or going back on one of the two refueling flatbed trucks seen out back of unit 3 in the satellite photos?

Are shiney, "new" low level enriched uranium (oxide?) fuel rods that have not been in a reactor extremely hot before the fission reaction has occurred in the core of a reactor?

If a fuel rod cask were being downloaded or uploaded, what would the actual process be? Might there be some point in the re-fueling or de-fueling process where the rods would be out of the racks and perhaps in a state or location more vulnerable to a disastrous accident like the current chain of events?

How robust are the racks and individual rod bundles that hold together a fuel rod assembly.

How robust are the casks in which fuel rod assemblies are transported?

If the fuel rods are spent (with respect to the level of fissionable materials present necessary to sustain an efficient chain reaction in the core), then would it be reasonable to suspect loosely scattered rods such as these pictured, if they were spent, would necessarily heat up more in their haphazard arrangement?

I don't know the answer to any of these questions.

 

[rhody]

Here are a few questions for those more sure than me to ponder:

What is a reasonable estimate of the mean age of spent fuel rods stored in a SFP after removal from the reactor? Is it possible that after many months or years in the SFP the rods might have exhausted the residual heat to level that they would not glow and might be lost in the background heat signature coming from the ruins of Unit 3?

What might become of the contents of one of those casks coming off or going back on one of the two refueling flatbed trucks seen out back of unit 3 in the satellite photos?

Are shiney, "new" low level enriched uranium (oxide?) fuel rods that have not been in a reactor extremely hot before the fission reaction has occurred in the core of a reactor?

If a fuel rod cask were being downloaded or uploaded, what would the actual process be? Might there be some point in the re-fueling or de-fueling process where the rods would be out of the racks and perhaps in a state or location more vulnerable to a disastrous accident like the current chain of events?

How robust are the racks and individual rod bundles that hold together a fuel rod assembly.

How robust are the casks in which fuel rod assemblies are transported?

If the fuel rods are spent (with respect to the level of fissionable materials present necessary to sustain an efficient chain reaction in the core), then would it be reasonable to suspect loosely scattered rods such as these pictured, if they were spent, would necessarily heat up more in their haphazard arrangement?

I don't know the answer to any of these questions.

TCups,

All very good, well organized, clearly stated questions... simple answer... where is Astronuc !

Rhody...

 

[TCups]

TCups,

All very good, well organized, clearly stated questions... simple answer... where is Astronuc !

Rhody...

On his way to Japan? He said that was his immediate goal if he could get there.

 

[dallasbrew]

cask integrity:

I don't know about modern ones, but back when I was going to nuke school, it was noted that they were designed to drop, burning from a truck on an overpass into the path of a train and not be compromised.

They are supposed to be pretty tough things.

 

[rhody]

On his way to Japan? He said that was his immediate goal if he could get there.

TCups,

To the best of my knowledge as of Sunday evening no, he said it would be some time before he may travel there. We could use his expertise since it revolves around the aging process of the fuel and fuel mixtures used. I am sure if he is about he will pop in and contribute.

Just to lighten the mood somewhat, don't you guys, TCups, AtomicWombat, etc... ever sleep ! Sometimes to step away for a bit allows your brain to mull things over and you come back with fresh insight. It happens for me once in awhile, mostly in the shower in the early am.

When this whole affair wraps up, hopefully positively, I hope you guys stick around and contribute your life skills, it has been interesting to watch to say the least.

Rhody...

 

[gmax137]

Here are a few questions for those more sure than me to ponder:

What is a reasonable estimate of the mean age of spent fuel rods stored in a SFP after removal from the reactor? Is it possible that after many months or years in the SFP the rods might have exhausted the residual heat to level that they would not glow and might be lost in the background heat signature coming from the ruins of Unit 3?

Mean age? probably 10 to 20 years. They would certainly not be 'glowing' hot.

What might become of the contents of one of those casks coming off or going back on one of the two refueling flatbed trucks seen out back of unit 3 in the satellite photos?

I expect they’re putting fuel into dry storage casks, though I really don’t know.

Are shiney, "new" low level enriched uranium (oxide?) fuel rods that have not been in a reactor extremely hot before the fission reaction has occurred in the core of a reactor?

The new fuel isn’t even warm to the touch. You could safely keep it in your kitchen.

If a fuel rod cask were being downloaded or uploaded, what would the actual process be? Might there be some point in the re-fueling or de-fueling process where the rods would be out of the racks and perhaps in a state or location more vulnerable to a disastrous accident like the current chain of events?

Not sure what you mean here. I don’t think the rods are pulled from the assemblies at any time.

How robust are the racks and individual rod bundles that hold together a fuel rod assembly.

They are very robust. If you dropped an assembly from the crane you might bend the first row.

How robust are the casks in which fuel rod assemblies are transported?

Here in the US they are extremely robust. Google for videos of the casks being hit by locomotive at high speed, etc.

If the fuel rods are spent (with respect to the level of fissionable materials present necessary to sustain an efficient chain reaction in the core), then would it be reasonable to suspect loosely scattered rods such as these pictured, if they were spent, would necessarily heat up more in their haphazard arrangement?

No, the arrangement doesn’t alter the heat generated in any given rod; the heat is just the fission products decaying away at their given rate.

I'm not a BWR guy so these are just my best guess answers. Hope that helps.

 

[TCups]

Aside:
OK, I bit the bullet and spent $2.99 (not auto renewing) and paid by PayPal so I have unlimited bandwidth for the next 30 days. The links in the previous posts should be working once more. Now I am even more "invested" I suppose.

 

[TCups]

Mean age? probably 10 to 20 years. They would certainly not be 'glowing' hot.I expect they’re putting fuel into dry storage casks, though I really don’t know.The new fuel isn’t even warm to the touch. You could safely keep it in your kitchen.Not sure what you mean here. I don’t think the rods are pulled from the assemblies at any time.They are very robust. If you dropped an assembly from the crane you might bend the first row.Here in the US they are extremely robust. Google for videos of the casks being hit by locomotive at high speed, etc.No, the arrangement doesn’t alter the heat generated in any given rod; the heat is just the fission products decaying away at their given rate.

I'm not a BWR guy so these are just my best guess answers. Hope that helps.

OK, so it would not be reasonable to expect a sideways blast into the SFP could "disassemble" a fuel rod assembly, I suppose. Probably not even with a shock wave traveling through water rather than air. But it seems possible, in the unlikely event that these are fuel rods, that they might not have a high heat signature in the IR range. Now we need some x-ray imagery of the site, I suppose.

The question of the origin of the unbent rods remains unanswered.

 

[AtomicWombat]

First IR image released in news broadcast

Hot spot over spent fuel pools indicated as 128 deg C and multiple hot spots at other places
(at the moment I cannot listen to the broadcast - only watch so no idea what they saying

Well 128 C means the SFP (assuming that is what it is) is definitely not covered with water (at atmospheric pressure) at the time of the IR photo. Steam at atmospheric pressure will usually only be at 100 C. So whatever is being viewed is solid or the solid crust of a molten mass.

Can anyone direct me to the original source of these IR images?

 

[AtomicWombat]

I tried last evening, for a good hour, to confirm from any independent source, the exact layout of the floor plans of any of the units at Fukushima.

Does anyone have a better source for the actual "anatomy" of what the Fukishima facility is supposed to be, rather than a stylized schematic? A blueprint or floor plan would certainly help to be able to draw more informed conclusions about what is seen.
Thanks.

TCups,
I think you can safely assume that the SFP and equipment pool straddle either side of the reactor on the long orientation of the reactor building (i.e the 45 m length). The large crane spans the 35 metre dimension of the building. So the SFP and equipment pool will be approximately centred on the north and south walls of each reactor building, or perhaps slightly offset from the centre line.

I think you are basically correct. The hole just above the steam is the SFP. The steam in the image comes from roughly from the "cattle run" between the reactor and the SFP. The hole to the right, with the "cut-out" of the steel frame above it, is the reactor plug hole.

 

[Reno Deano]

Here are a few questions for those more sure than me to ponder:

What is a reasonable estimate of the mean age of spent fuel rods stored in a SFP after removal from the reactor? Is it possible that after many months or years in the SFP the rods might have exhausted the residual heat to level that they would not glow and might be lost in the background heat signature coming from the ruins of Unit 3?

At one time before moving "old" spent fuel from the SFP to Dry Casks, the age could have been 10 years or more. Due to the 2/3 burn-up the long lived fission products (Cs-137, PU, etc, would give then a good heat signature.

What might become of the contents of one of those casks coming off or going back on one of the two refueling flatbed trucks seen out back of unit 3 in the satellite photos?

Coming off the truck they would be empty. Going on they would be full and destined for fuel reprocessing in France

Are shiney, "new" low level enriched uranium (oxide?) fuel rods that have not been in a reactor extremely hot before the fission reaction has occurred in the core of a reactor?

HE fuel bundles (navy type is room temperature.) LE Fuel bundles is less than room temperature, and individual rods are ambient temperature.

If a fuel rod cask were being downloaded or uploaded, what would the actual process be? Might there be some point in the re-fueling or de-fueling process where the rods would be out of the racks and perhaps in a state or location more vulnerable to a disastrous accident like the current chain of events?

Spent fuel bundles/modules are either loaded into casks under water or by a shielded transfer container. Pieces of rods are keep out of the casks.

How robust are the racks and individual rod bundles that hold together a fuel rod assembly.

Robust enough to withstand high pressure oscillations with within the core and incidents normal to transportation. The SFP racks are designed with seismic considerations.

How robust are the casks in which fuel rod assemblies are transported?

Almost indestructible. Goggle: DOE Spent Fuel Shipping Cask Testing

If the fuel rods are spent (with respect to the level of fissionable materials present necessary to sustain an efficient chain reaction in the core), then would it be reasonable to suspect loosely scattered rods such as these pictured, if they were spent, would necessarily heat up more in their haphazard arrangement?

The picture is from a fuel manufacturing facility, prior to them being placed into the fuel bundle matrix/array. Spent fuel rods from power reactors would be oxidized and not sparkling.
I don't know the answer to any of these questions.

See italicised answers below your questions.