Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[LanceV]

@minerva:
Thanks for the hint at the KEK data.

You write in your blog:

This is not an injection of seawater into any part of the nuclear reactor or the Nuclear Steam Supply System itself. It is an injection of seawater into the containment structure surrounding the reactor pressure vessel.

Are you sure of this?
In the TEPCO press releases they explicitly say:
"We have been injecting sea water into the reactor pressure vessel."
http://www.tepco.co.jp/en/press/corp-com/release/11031905-e.html
Also the JAIF assumes that sea water is injected into the containment as well as into the pressure vessel in Reactor 1 and 3 and only into the RPV in reactor 2:
http://www.jaif.or.jp/english/

Maybe something is lost in translation, but the rising and falling water levels in the RPV also seem to indicate that water is injected somewhere.
At first I was a bit surpised as well, since there seems to be a danger of a steam explosion if you resubmerge bare fuel rods into the water again, but maybe it is possible.

 

[jinxdone]

Have you taken a look at http://www.youtube.com/watch?v=CmI2lXiTo-g" yet? Rather dubious taking note of the name of the poster and his other videos.. But anyhow, maybe it has some detail to it otherwise missed.

 

[Reno Deano]

From a radiological engineering perspective, it will be nice to see if the TMI upgrades in reactor accident coolant sampling (automated and shielded microliter sampling). At TMI when they tried to do normal coolant sampling 3/8' piping the radiation levels spiked in the sampling room due to fission particle and gases being introduced. The Rad Techs High Range GM Teletectors pegged (>1,000 R/hr). The Techs we shaken mentally at such high radiation levels.

 

[TCups]

Have you taken a look at http://www.youtube.com/watch?v=CmI2lXiTo-g" yet? Rather dubious taking note of the name of the poster and his other videos.. But anyhow, maybe it has some detail to it otherwise missed.

I have now . . . Here are some enhanced stills from the video.

The top of the reactor vessel spewing steam. Note the round hole blasted through the superstructure of the building roof. I believe that to be the equipment pool in the upper left of the photo.

This is what steel reinforcement rods (rebar) left behind after an outward blast with the concrete blown away. They are bent and bow outward.

On the other hand, this is what I think a smashed fuel rod assembly within the rubble after the blast might look very much like. Comments?

I don't know what the yellow stuff is. If it is insulation, and it may be, then there isn't very much of it anywhere else in any of the frames, which makes that interpretation somewhat worrisome. Anyway -- yellow stuff. . .

 

[Thermalne]

On the other hand, this is what I think a smashed fuel rod assembly within the rubble after the blast might look very much like. Comments?

That looks more like a damaged crane structure to me.

I don't know what the yellow stuff is. If it is insulation, and it may be, then there isn't very much of it anywhere else in any of the frames, which makes that interpretation somewhat worrisome. Anyway -- yellow stuff. . .

Looks like piping insulation.

 

[Angry Citizen]

For all y'all know, they're teddy bears. These are grainy photographs of an obliterated structure. Trying to analyze it is futile in my opinion.

One thing we do know is that no corium could possibly be visible in any photograph. The radiation readings would be orders of magnitude higher.

 

[DR13]

CNN has two opinion articles on oppsite sides of the issue:

Anti-Nuclear:
http://www.cnn.com/2011/OPINION/03/19/cooke.nuclear.history/index.html?hpt=C2

Pro-Nuclear:
http://www.cnn.com/2011/OPINION/03/19/chesser.nuclear.future/index.html

The main problem I have with the anti-nuke article is that is references problems from the 50s and 60s and makes no mention of the fact that nuclear safety has progressed. The author keeps saying that it is obvious that eventually something really really bad will happen.

The pro article brings up a lot of points that most people don't consider. For instance, if there is a catastrophic problem at a nuclear plant then bad things happen. Ironically, when fossil fuels are used correctly then bad things happen (climate change, war for oil, etc).

 

[TCups]

That looks more like a damaged crane structure to me.

Which part of this looks like that?

Looks like piping insulation.

Yes, it does. But I am looking hard for any more of it. And it initially looked like the yellow insulation was hanging out the side of the building, not out of the side of the broken pipe. Lots of other broken pipes around without exposed yellow insulation. Look at the transected end of the pipe on the right. The thick wall of the steam pipe (probably 40 years old) looks to be asbestos-insulated.

As I said, though, I don't know what it is.

. . . and it is a nuclear engineering opinion that would be most valuable now, not an anti-nuc or pro-nuc opinion (but I haven't read the pieces, yet. BTW, in disclosure, I count myself in the pro-nuc category).

 

[Reno Deano]

NRC release FAQs regarding the Japanese reactor accidents and how they apply to US reactor sites.

http://www.nrc.gov/japan/faqs-related-to-japan.pdf"

 

[TCups]

For all y'all know, they're teddy bears. These are grainy photographs of an obliterated structure. Trying to analyze it is futile in my opinion.

Then close your eyes. I intend to keep mine open and keep looking. There is always information to be had in photos like these. If not, then someone sure took some outrageous risks on a futile mission. Let's hope the good guys have better quality copies of the images.

One thing we do know is that no corium could possibly be visible in any photograph. The radiation readings would be orders of magnitude higher.

I keep hearing that, but that presupposes that a) someone knew "corium" was likely to be there before they took the pictures, and b) that is is not possible someone would risk their life to get confirmatory pictures. Where nuclear disasters are concerned, we know both of those assumptions are historically inaccurate. And for the record, I never said it was corium.

PS, Angry, just FYI:

This is a teddy bear:
http://images.free-extras.com/pics/t/teddy_bear-539.jpg

and this is a smoldering reactor building:

and that, I am sure of.

The large, round area (circle), is, in my opinion, the top of the reactor. There may be some railing left intact around it. It looks more like a hole with steam coming out of it than an intact plug, but I can't tell. There are no intact roof girders over it. It seems plausible that the plug may have been blown, though. The square would appear to be the equipment pool at the side of the reactor. i wasn't able to identify what I thought was the SFP with certainty.

 

[jinxdone]

Here's how I interpret the flight path(red) of the early part of the video, and what you are seeing(green). Just before reaching reactor building 1 the camera switches sides to the mainland side and from then the view is almost vertically down. Just in case anybody else was wondering.

 

[AntonL]

At time of disaster nuclear fuel was being transported in casks and presumably loaded or offloaded at reactor 3 as two cask transporters are seen parked outside

Transporter with escort and storage facility are library picture for reference

 

[AntonL]

NHK reports
Workers at the Fukushima Daiichi nuclear power plant are preparing to release gases from the overheating Number 3 reactor to lower pressure inside its container vessel.

The Nuclear and Industrial Safety Agency said on Sunday that pressure inside the vessel is rising despite efforts to cool the reactor.

The agency said the workers will first try to vent gases through a suppression pool to reduce the amount of radioactive substances released into the environment.

If the pressure doesn't decline, the officials will release gases directly from the vessel. If that happens, the level of radioactive iodine in the air will increase by 100-fold.

overheating No 3 reactor! not good news

 

[jensjakob]

Take a look at page 16 in this:
http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

The square hole looks like to at the place of the lift-tunnel that goes to the ground-level.

Leaving the smoking to come from the SFP. And the plug should be to the right of the SFP.

So, your analysis is a bit wrong as to which is which - but - it places IMHO the smoke as coming directly from the SFP.

The caskets on the trucks are interesting though.

 

[jensjakob]

If the pressure doesn't decline, the officials will release gases directly from the vessel. If that happens, the level of radioactive iodine in the air will increase by 100-fold.[/I]

overheating No 3 reactor! not good news

http://www3.nhk.or.jp/daily/english/20_19.html

Venting from an overheating MOX core - what are the isotopes involved?

 

[jensjakob]

1. How come that reactor 3 goes from "stable" (http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300584349P.pdf ) to high and need venting?

2. Why is it that radiation north of service building keeps on rising?
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300584349P.pdf

 

[jensjakob]

Official report:
"There is immediate threat of
radioactive nuclides release from the spent fuel pools of Unit 3 and
4, because of incapability of cooling these pools."
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300590001P.pdf

 

[AtomicWombat]

One thing we do know is that no corium could possibly be visible in any photograph. The radiation readings would be orders of magnitude higher.

Angry Citizen, do you have any evidence to support your assertions? At Chernobyl, photographs were taken of corium at close range.

Note the steel steam pipe has not melted in the last image.

The radiation measurements we have seen so far are not inconsistent with exposed corium:
https://www.physicsforums.com/showpost.php?p=3196528&postcount=491
https://www.physicsforums.com/showpost.php?p=3196602&postcount=495
https://www.physicsforums.com/showpost.php?p=3197079&postcount=526

Workers were exposed to corium at Chernobyl for brief periods - most survived. I have heard some reports of emergency workers at the Fukushima falling ill with symptoms suggestive of radiation poisoning, but the condition is insidious, with death after lethal levels of exposure taking up to three months:
http://www.nytimes.com/2011/03/16/world/asia/16workers.html?pagewanted=all"
"Among plant employees and firefighters at Chernobyl, many volunteered to try to tame, and then entomb, the burning reactor — although it is not clear that all were told the truth about the risks. Within three months, 28 of them died from radiation exposure. At least 19 of them were killed by infections that resulted from having large areas of their skin burned off by radiation, according to a recent report by a United Nations scientific committee. And 106 others developed radiation sickness, with nausea, vomiting, diarrhea and dropping blood counts that left them highly vulnerable to infections. "

I don't have confidence that we would be told the full details about cases of radiation sickness in this incident. Do you?

 

[AtomicWombat]

http://i306.photobucket.com/albums/nn270/tcups/90f8736d.jpg

The large, round area (circle), is, in my opinion, the top of the reactor. There may be some railing left intact around it. It looks more like a hole with steam coming out of it than an intact plug, but I can't tell. There are no intact roof girders over it. It seems plausible that the plug may have been blown, though. The square would appear to be the equipment pool at the side of the reactor. i wasn't able to identify what I thought was the SFP with certainty.

http://i306.photobucket.com/albums/nn270/tcups/Picture7-2.png

Hi TCups,
I've examined the reactor building frames and made some measurements on Google Earth. Reactors 2, 3 and 4 have roof dimensions about 35 by 45 metres (120 by 150 feet). I believe they are about 55-60 metres tall although this is harder to estimate. The short dimension (35 m) is spanned by 4 spans - held up by 5 rows of vertical beams. The longer dimension (45m) is spanned by 6 spans - held up by 7 rows of vertical beams.

This is consistent with this diagram:

The mouth of the primary containment - the concrete flask that holds the reactor is about 10-12 metres across. I believe I am in agreement with you in that the evidence suggests that the "concrete shield plug" has been blasted out of the building by an explosion originating deep in the containment. In my view https://www.physicsforums.com/showpost.php?p=3192987&postcount=304":

"The explosion last Monday was directed strongly vertically suggesting to me it originated from deep within the containment structure. It clearly carried substantial solid material to a height of 400-500 metres. Whilst I can't be sure this may have been due to a melt-down of the fuel rods in reactor 3. They melted through the reactor floor (1500 Celsius) and fell into the flooded "dry-well" below. This triggered a large steam- zirconium-water-hydrogen explosion. I suspected this not only blew the concrete top off the containment, it also blew most of the reactor contents out of the reactor."

This explosion was clearly different in nature from the explosion of building 1 which was directed horizontally, with the debris cloud not exceed the height of the stack (120-150 metres). The explosion of building 3 can be likened to the popping of a champaign cork - the shape of the flask directs the energy vertically.

I suspect the hole you have identified is too large to be just the reactor mouth. My impression from the available drawings and the video is the RHS of the hole is the open reactor mouth and the LHS is some form of deep storage pool, perhaps for spent fuel (SFP), equipment etc.

As to the fuel rods and yellow material, they are suggestive, but I'm unsure. Where are the other components of the fuel assemblies - the spacers and channels (external box)?

And I keep seeing image artefacts suggestive of hot spots, even http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichirec_march17_2011_dg.jpg" . I'm still looking for corroborative evidence (or otherwise).


Note, http://www.nucleartourist.com/areas/bwr-in1.htm"

 

[TCups]

Take a look at page 16 in this:
http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

The square hole looks like to at the place of the lift-tunnel that goes to the ground-level.

Leaving the smoking to come from the SFP. And the plug should be to the right of the SFP.

So, your analysis is a bit wrong as to which is which - but - it places IMHO the smoke as coming directly from the SFP.

The caskets on the trucks are interesting though.

Jens:

I agree with your analysis. One of the two trucks seems to still have its casket. The second truck is partially covered with debris -- I can't tell if it is an empty cradle where the casket used to be or if the casket is just covered with debris and harder to see. Also, it appears that the smoke/steam is coming from a point source and spreading out, perhaps as if leaking from a pipe or crack, not rising from the entire surface of the area of the pool. I believe that point might be near the gate connecting the SFP with the containment wall outside the reactor vessel -- do you agree?

Also, it seems to me that the fly-over footage spent a lot of time looking at the debris field on the ground. Leads me to wonder if they were looking for something in particular. Don't know.

 

[AtomicWombat]

The square would appear to be the equipment pool at the side of the reactor. i wasn't able to identify what I thought was the SFP with certainty.

I agree with jensjakob, the square hole appears to be a lift well for fuel elements.

 

[AntonL]

And I keep seeing image artefacts suggestive of hot spots, even http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichirec_march17_2011_dg.jpg" . I'm still looking for corroborative evidence (or otherwise).

I think you are referring to the white dots with red or green around them - overexposure from reflected sunlight from a metal sheet. You can see lots of them in the harbor when sun reflects of the water.

 

[AtomicWombat]

Interesting article on the UCS site on the operations & dimensions of the spent fuel pool.

http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at"

 

[minerva]

http://www3.nhk.or.jp/daily/english/20_19.html

Venting from an overheating MOX core - what are the isotopes involved?

The same fission products as any other reactor, really. The fact that it's MOX fuel is not really significantly different; the fission products are pretty much the same as any other reactor and the plutonium itself is not significant.

 

[swimmer]

http://www3.nhk.or.jp/daily/english/20_19.html

Venting from an overheating MOX core - what are the isotopes involved?

Update: No gases to be released from No. 3 reactor
http://www3.nhk.or.jp/daily/english/20_23.html"

 

[minerva]

Interesting article on the UCS site on the operations & dimensions of the spent fuel pool.

http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at"

Personally, I don't take UCS very seriously. I always remember the fact that, despite working with them closely on disarmament and arms control issues, Hans Bethe refused to join UCS because they were fundamentally opposed to all nuclear power, a position that Bethe refused to endorse.

Of the thousands of nuclear physicists and nuclear engineers across the United States, they found themselves with a couple who became anti-nuclear activists - like Lochbaum.

Lochbaum's claims about a Zircaloy fuel cladding fire have been debunked... simply by actually doing a simple experiment.

https://www.youtube.com/watch?v=x__2yWx9zGY

 

[AntonL]

What caused the welds on these pipes to break and unfurl?

 

[Reno Deano]

MOX fuel is different, I beg to differ. Higher gap fission product migration/releases, etc. Burns different. If melted will release 100 times mores plutonium than standard LEU fuel rods. See NRC Safety Analysis for putting MOX in US reactor:

http://adamswebsearch2.nrc.gov/idmws/DocContent.dll?library=PU_ADAMS^pbntad01&LogonID=026baa2ac948650fffa957db74869764&id=040970215

Excerpt: Table 1: Nominal Unirradiated Fuel Isotopics, %
U.S. European Proposed
Isotope LEU MOX MOX LTA
wt% 234U / U 0.03 ---- ----
wt% 235U / U 3.2 0.24 - 0.72 0.35
wt% 236U / U 0.02 ---- ----
wt% 238U / U 96.75 92.77 95.28
wt% 238Pu / Pu ---- 0.88 - 2.40 0.05
wt% 239Pu / Pu ---- 53.8 - 68.2 90.0 - 95.0
wt% 240Pu / Pu ---- 22.3 - 27.3 5.0 - 9.0
wt% 241Pu / Pu ---- 5.38 - 9.66 1.0
wt% 242Pu / u ---- 2.85 - 7.59 0.1
wt% Pu / HM ---- 4.0 - 9.0 4.37
wt%Fissile / HM 3.2 3.65 - 5.25 #4.15
HM = Pu + U. May not sum to 100% due to rounding and ranges. Derived
from data in licensee submittal, ORNL/TM-2003/2 [Ref.1], NUREG/CR-0200 V1 [Ref.2]
The two MOX fuel types differ in that the relative concentrations of plutonium and uranium and
the distributions of their isotopes differ. Table 1 above compares the distribution of fissile and
non-fissile isotopes in typical LEU fuel, typical commercial reactor-grade MOX fuel, and the
proposed MOX LTAs. The differences in the initial fuel isotopics are potentially significant to
accident radiological consequence analyses since the distribution of fission products created
depends on the particular fissile material. If the fissile material is different, it follows that the
distribution of fission products may be different. For example, one atom of I-131 is created in
2.86 percent of all U-235 fissions, whereas one atom of I-131 is created in 3.86 percent of all
Pu-239 fissions. This is an illustrative example only in that the radionuclide inventory in the fuel
at the end of core life depends on more than fission yield. Nonetheless, this shift in the fission
product distribution needs to be evaluated for its impact on the previously calculated
radiological consequences of DBAs.
The LEU fuel is enriched in the U-235 isotope, an operation that occurs on a molecular scale
while the UO2 fuel is in the gaseous phase. This processing results in fuel pellets with a high
degree of homogeneity and uniform grain sizes. The proposed MOX LTA fuel will be
manufactured in a process that involves blending of UO2 and PuO2 powders to achieve the
desired Pu content. The MOX fuel pellets, therefore, are not as homogeneous as an LEU fuel
pellet. This difference in pellet structure has the potential to affect the diffusion of fission gases
through the fuel pellet and may impact the fraction of the pellet fission product inventory that is
in the fuel rod gap between the pellet outer surface and fuel clad inner surface (i.e., gap
fraction). It is generally understood that the fission gas release (FGR) rate for MOX fuel is
greater than that for LEU fuel, given comparable enrichments and burnups. This behavior is
primarily explained by the lower thermal conductivity of MOX fuel pellets that results in higher
fuel temperatures than in LEU rods. Since the gap fractions are an input to the analyses of
calculated doses from non-core melt DBAs, changes to the gap fractions associated with MOX
fuel need to be considered

 

[AntonL]

Interesting article on the UCS site on the operations & dimensions of the spent fuel pool.

http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at"

I would be more interested to know how it came to a hydrogen explosion in reactor 4.
That all the water boiled away to expose the fuel just does not seem possible to me,
as then by now all the fuel rods would have been exposed and a huge fire would be witnessed
TEPCO always stressed that there is enough water in SFP so hydrogen generation could not have
been from the SFP. So from where was H2 generated?

We recap the source of the hydrogen is: The claddings of the fuel rods which keep the fuel together
are made from alloys of zirconium. When the rods are no longer covered by water during an accident they
reach temperatures much higher than they designed for, and the metal starts to oxidize at about 1000 °C.
Since there is no free oxygen around the reactor core the metal reacts with the water vapour and takes
the oxygen from there. When oxygen is removed from the water molecule hydrogen is left.

Now I must be careful in italics below is just my imagination and speculation and not reality:
Various cross sections Of the reactors show a smaller pool or equipment pool. Let's suppose some of the
equipment pools water was "borrowed" to make up lost water in the neighbouring reactors, this would save
the reactors (once sea water injection started the reactors are scrapped), Also remember Hilary Clinton
at the beginning of the catastrophe announced that USA is urgently sending special coolant to the site,
thus "borrowing" water from the equipment pool does not seem to be a bad and dangerous decision;
unless supposedly some fuel was stored in the equipment pool of unit 4 as the SFP is completely full
because of maintenance. This could explain the hydrogen development and the two short lived fires
that self extinguished in reactor 4, and lay weight to the speculation in this thread regarding the molten mass.

Time Line:
Unit 1: 11th 16:36 Event falling under Article 15* occurred (Incapability of water injection by core cooling function)
Unit 2: 11th 16:36 Event falling under Article 15* occurred (Incapability of water injection by core cooling function)
Unit 3: 13th 05:10 Event falling under Article15* occurred (Loss of reactor cooling functions) (Two days later)
Unit 4: 15th 09:38 Fire occurred on extinguished spontaneously
Unit 4: 16th 05:45 Fire occurred on extinguished spontaneously

 

[Reno Deano]

NEI has release a White Paper on BWR Mk-1 Containment Status and History.

http://www.nei.org/resourcesandstats/documentlibrary/reliableandaffordableenergy/reports/report-on-bwr-mark-i-containment/"

Interesting information on Mark 1 containment analyses and required upgrades.

 

[Reno Deano]

IAEA officials will hold a briefing today Sunday for journalists to discuss the nuclear emergency in Japan.

The briefing will begin at 16:30 CET on Sunday, 20 March 2011, in the Press Room of the M-Building, in the Vienna International Centre (VIC).

http://www.iaea.org/press/"

NRC to hold public meeting on Japanese Reactor crises March 2st, 2011

http://www.nrc.gov/public-involve/public-meetings/webcast-live.html"

 

[rogerl]

Just wondering.. how come nuclear plants don't install cameras inside the reactor core itself so they can see it live? Even a $10 video camera module at Radio Shack would be effective. Cost cutting in Japan?

 

[Astronuc]

Just wondering.. how come nuclear plants don't install cameras inside the reactor core itself so they can see it live? Even a $10 video camera module at Radio Shack would be effective. Cost cutting in Japan?

Camera's are used at some distance. Normal camers would get fried by the radiation. Cameras are not suited for 285C (555 F) operating temperatures or pressures ~72 atm (~1055 psia). Even rad-resistant cameras can only take so much before the glass turns brown due to radiation.

GE's comments on the Fukushima matter
http://www.gereports.com/facts-on-the-nuclear-energy-situation-in-japan/
http://www.gereports.com/setting-the-record-straight-on-mark-i-containment-history/

http://files.gereports.com/wp-content/uploads/2011/03/GEA14883C-AdvanBWR_LR.pdf

 

[Reno Deano]

Just wondering.. how come nuclear plants don't install cameras inside the reactor core itself so they can see it live? Even a $10 video camera module at Radio Shack would be effective. Cost cutting in Japan?

They (cameras) would become another piece of rad waste to chuck out, plus they would jeopardized fuel bundle channels when they broke apart during reactor operations. I do not know of any devices currently installed with in a RPV that has electrical cables attached and are as flimsy as a Radio Shack camcorder. How would you broadcast the images? WIFI, I don't think so. Take the video camera of your choice and put it into a pressure cooker and in the oven set at 500 + degrees F and see how long it continues to broadcast via WIFI.

 

[Angry Citizen]

Angry Citizen, do you have any evidence to support your assertions?

For one, post #526 quoted another post which disagreed with the assertions. Two, the radiation levels at Fukushima are not indicative of corium release. The following chart compares radiation levels at Fukushima next to known corium releases:

http://upload.wikimedia.org/wikipedia/en/f/fd/Fukushima_map.png

What it shows is that one reactor from Chernobyl was releasing orders of magnitude more radiation than four damaged reactors at Fukushima. This displays a high degree of confidence that no corium has escaped into the environment.