Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Reno Deano]

TEPCO's latest update. I am assuming they mean that no water has leaked from the RPV to the Primary containment, which is questionable.

Press Releases

Press Release (Mar 19,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 0:00 pm March 19th)


No New Developments since 9:00pm, 19th March

Unit Status
1 • Reactor cold shutdown, stable water level, offsite power is
available.
• No cooling water is leaked to the reactor containment vessel.
• Maintain average water temperature at 100°C in the pressure
restraint.
2 • Reactor cold shutdown, stable water level, offsite power is
available.
• No cooling water is leaked to the reactor containment vessel.
• Maintain average water temperature at 100°C in the pressure
restraint.
3 • Reactor cold shutdown, stable water level, offsite power is
available.
• No cooling water is leaked to the reactor containment vessel.
• Maintain average water temperature at 100°C in the pressure
restraint.
4 • Reactor cold shutdown, stable water level, offsite power is
available.
• No cooling water is leaked to the reactor containment vessel.
• Maintain average water temperature at 100°C in the pressure
restraint.
other• In the Unit 1, 2, 3 and 4, which automatically shut down due
to the Tohoku-Chihou-Taiheiyo-Oki Earthquake on March 11th, 2011,
we had been preparing measures for decreasing the pressure of each
reactor containment vessel since March 12th. However, on March
17th, we released such preparation in all of the Units.

 

[turbo]

Our military has some very capable autonomous/remote controlled rotor-wing aircraft with visual/IR imaging systems, like the RQ-8A Fire Scout. It is hard to believe that such drones have not been tasked with getting better images than the ones that the public can access. I can understand the military not wanting to disclose the capabilities of their surveillance systems, but this is a pretty dicey situation and more accurate imaging (and not just top-down shots) could be very valuable in assessing damage and charting out a course of action for each damaged reactor.

 

[LanceV]

I wish anyone would publish SOME radiation readings ...

The GRS has been compiling the some of the known radiation data in some nice diagrams (in german but should be self-explanatory):
http://www.grs.de/informationen-zur-lage-den-japanischen-kernkraftwerken-fukushima-onagawa-und-tokai
Especially
http://www.grs.de/sites/default/files/Radiation-Data_Daiichi_20110319-1800.pdf and
http://www.grs.de/sites/default/files/ODL-Werte-Poll_20110319_1715_0.pdf
are interesting.

 

[M. Bachmeier]

Japan reluctant to disclose footage of power plant taken by U.S. drone


http://mdn.mainichi.jp/mdnnews/news/20110319p2a00m0na005000c.html

 

[Angry Citizen]

Note: This is regarding the second link.

It is by no means 'self-explanatory' -- I had to utilize translation software. It is saying that radiation levels less than half a kilometer away from all six reactors has peaked at about five millisieverts/hour for the past several days. This seems to be good news. The purple spikes correlate to the explosions, with the largest one also correlated with the fire at unit 4. I want to know why the main building (Hauptgebäude) is continually reading what appear to be spikes -- large increases followed by exponential decrease.

 

[MadRocketSci2]

My understanding is that when they perform steam venting operations, there is a brief spike in the observed radiation.

 

[83729780]

TEPCO's latest update. I am assuming they mean that no water has leaked from the RPV to the Primary containment, which is questionable.

Press Releases

Press Release (Mar 19,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 0:00 pm March 19th)

not Daiichi

 

[edmundredmark]

Lurker de-cloaking here partly to say thanks to the knowledgeable participants and excellent photo researchers in this thread and partly to make a few random comments:

A) On useful vs. stupid coverage of this event: I've been using mainly the New York Times and Kyodo News for news, and I think they've been, not perfect, but pretty thorough and accurate. (For instance, somebody asked a few pages back 'where are our Predator drones'? Well, that was answered by the NYT a day or two ago: there is indeed one in use, and other military surveillance assets normally targeted at North Korea are also being used over the Fukushima site.) With the Times, you have to keep checking back, however -- they do this kind of running update to their main article, rather than publishing a new story every time something new happens.

I've also found the information from the Union of Concerned Scientists and the MIT Dept. of Nuclear Engineering to be valuable.

B) Seems clear that the central issue here at Fukushima is the extended "station blackout". As a layman who went to college (and only a state college, to boot!) and has some decent reasoning capabilities, I'm more than a little aghast that, apparently, in all the emergency contingency planning for NPPs it is simply assumed that a station blackout could never last more than 4-8 hours. I don't think NPPs should be forced to plan for events as unlikely as, say, an attack by Martians, but an event that could knock out grid power and your only set of emergency generators for more than 4 (or, at best, 8) hours? C'mon guys. I think that's grossly irresponsible safety planning, and though I'm not anti-nuclear at all, I am very strongly anti-stupidnuclear.

I look at San Onofre and Diablo Canyon in earthquake-prone California and think they've got to do some serious, and quick, thinking about how to increase redundancy and survivability in their power supplies. Just simply putting some additional diesel generators in a hurricane/tornado/earthquake hardened building a few hundred feet up the hill to a nice elevation, and running some electrical cable underground to the reactor buildings would seem like a simple, and prudent, step that could be taken pretty much now. If I lived in California I would push my elected officials to mandate it now (and be willing to pay a special sales tax or something to pay for it). But I majored in English, so what do I know.

C) One thing on media coverage that I think would be useful is the information that one of the health risks being talked about most here, which is thyroid cancer induced by accumulation of Iodine-131 in the thyroid gland, is actually not that serious a public health threat, relatively speaking. So-called Differentiated Thyroid Cancer (the kind produced by radiation damage) is almost 100% curable in any modern medical system. It ain't fun, but it's not a medical catastrophe in nearly all cases. (I've had it, so speak from personal experience.)

Diablo Canyon NPP:

San Onofre NPP:

[PLAIN]http://images.ocregister.com/newsimages/undefined/2008/07/30_sanonofre1_large.jpg

 

[minerva]

This is interesting.

http://abclocal.go.com/kgo/video?id=8021906

A Zircaloy fuel cladding tube gets introduced to an oxyacetylene torch. It does not actually appear to melt or burn at that temperature.

Are any of you with better nuclear engineering expertise than me able to comment on that? Is it a myth that the Zircaloy actually "catches fire" if heated in air?

There is a lot of very good radiological data coming out of the KEK experimental physics centre in Tsukuba, outside Tokyo.

http://rcwww.kek.jp/norm/index-e.html

Above is their real-time gamma dose monitor.

They also have some very high resolution gamma spectroscopy data, showing the levels of several different significant fission products.

http://www.kek.jp/quake/radmonitor/GeMonitor2-e.html

These fission products are definitely from Fukushima, and they are there at detectable levels – but these instruments are incredibly sensitive, and these levels are absolutely harmless.

We can see the short-lived ¹³²Te dropping away readily over time, as it decays, which makes perfect sense.

We’re talking about, for example, 2 nBq (yes, nanobecquerels) of ¹³⁷Cs per cm³ of air at the moment.

Over the last week I've written a few blog posts about the Fukushima NPP incident as this has been developing. I'm sure some of you might find these posts useful or informative or interesting.

http://reindeerflotilla.wordpress.com/2011/03/19/fukushima-updates-march-18/

http://reindeerflotilla.wordpress.com/2011/03/13/all-right-its-time-to-stop-the-fukushima-hysteria/

http://reindeerflotilla.wordpress.com/2011/03/16/fukushima-redux/

I would certainly love to hear some comments, or peer-review from the more qualified nuclear engineers out there in the audience.

Would anyone care to peer-review my physics on the water loss rate in the used-fuel pool?

I'm still wondering, to be honest, why the LPCIs aren't working at Fukushima I. We know that HPCI can only run for a limited amount of time after SCRAM because there's only a limited amount of heat and steam pressure available in the nuclear steam supply system. RCIC runs on batteries during a station blackout, and those batteries only last for a finite amount of time.

But as far as I understand it, LPCI is designed to run on its own diesel-driven pumps, for days, even without station power, until the heat in the core dropped to the point where cold shutdown is reached.

Can someone explain to me why every single layer of the ECCS seems to have failed at these reactors?

 

[Astronuc]

Regarding the spent fuel pool, see -

Question about spent fuel rod cooling pools in Japàn reactor
https://www.physicsforums.com/showthread.php?t=481599

https://www.physicsforums.com/showpost.php?p=3197363&postcount=12


Zr fires are a concern at the Zr-alloy manufacturing plant - but primarily due to the fines or fine wires that could catch fire. The concern in the pool would be rapid oxidation and the deterioration of the cladding, although some raise the concern of a Zr fire. If the protective oxide cracks, it may be possible to achieve oxidation. Zr + O2 => ZrO2 is exothermic.

The questions for a SFP fire are:

1. Under what conditions does Zr or Zr alloys 'burn'?

2. Are such conditions realized with exposed Zr alloy cladding in a dry or emptied SFP?

Elsewhere I've commented about the manufacturing of Zr alloys in which hot ingots are hot worked to logs for the production of billets.

 

[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.

 

[rhody]

An observation, the US media seems to have "moved on" to the Libyan and other issues, there are no followup or current stories edit: (Google News, 9: 45 EST) regarding containment/cleanup status of the crippled reactors in Japan. I guess I should not be surprised, but I find it odd to say the least, considering the long term implications of this disaster for Japan and the world.

Rhody...

 

[Angry Citizen]

An observation, the US media seems to have "moved on" to the Libyan and other issues, there are no followup or current stories regarding containment/cleanup status of the crippled reactors in Japan. I guess I should not be surprised, but I find it odd to say the least, considering the long term implications of this disaster for Japan and the world.

Rhody...

In my opinion, this is good news. The mass media are vultures. If they're not reporting on Fukushima, it means the situation has stabilized such that they can't induce even artificial panic among the populace like they've been doing. And that's not to downplay the severity of this incident -- it just seems like the Japanese have it handled now. That may be premature optimism, but I have reasons. Notably, power is being restored, radiation levels are dropping, the attempts to cool the spent fuel ponds were successful, and like I said, news media is running grudgingly optimistic stories of successes -- buried amidst their usual nonsense so that few will see it, of course. Forgive my cynicism.

 

[rogerl]

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.

Oh. I watched Discovery Channel "Disaster at Chernobyl" with the timeline of the disaster and there was this part where the worker inside the reactor core saw the fuel rods vibrating and try to wave to the camera connected to the control room. Thought it was accurate reenactment. Darn Discovery channel.

 

[rhody]

In my opinion, this is good news. The mass media are vultures. If they're not reporting on Fukushima, it means the situation has stabilized such that they can't induce even artificial panic among the populace like they've been doing. And that's not to downplay the severity of this incident -- it just seems like the Japanese have it handled now. That may be premature optimism, but I have reasons. Notably, power is being restored, radiation levels are dropping, the attempts to cool the spent fuel ponds were successful, and like I said, news media is running grudgingly optimistic stories of successes -- buried amidst their usual nonsense so that few will see it, of course. Forgive my cynicism.

Angry,

I agree with you, the media in general moves from one crisis de jour to the next. Let's hope what you said in your post: "power is being restored, radiation levels are dropping, the attempts to cool the spent fuel ponds were successful" holds and improves with time.

AntonL,

Can you give us a bit more detail on your post https://www.physicsforums.com/showpost.php?p=3198828&postcount=591" above, excerpt below:

Lets 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.

This sounds like a reasonable approach to me, mixing special coolant and borrowing water from a containment pool to cool fuel and or spent fuel which presents more of an imminent danger. Bright thinking by the nuclear power experts who proposed and then briefed Secretary of State Clinton of the strategy.

Just for clarification to those new to this thread, which reactor uses the reprocessed plutonium mixed oxide fuel (MOX), and if I understand correctly could release much more toxic radiation artifacts ?

Finally, it was reported earlier in this thread that spent fuel may have been moved, and the vehicle was abandoned in the explosion events, and two vehicles can be seen in the high resolution photo posted here. If so what hazard do the sealed container(s) with spent fuel present if left unattended for significant periods of time ?

Thanks...

Rhody...

 

[AntonL]

AntonL,

Can you give us a bit more detail on your post https://www.physicsforums.com/showpost.php?p=3198828&postcount=591" above, excerpt below:

This sounds like a reasonable approach to me, mixing special coolant and borrowing water from a containment pool to cool fuel and or spent fuel which presents more of an imminent danger. Bright thinking by the nuclear power experts who proposed and then briefed Secretary of State Clinton of the strategy.

Rhody...

There is no more detail!

Please read in full content, I started with:
Now I must be careful in italics below is just my imagination and speculation and not reality:
(I now have highlighted this in original post)

I was just imagining what resources and options that disaster management had - I repeat just imagination

As such, to my knowledge, No such proposal as Rhody mentions was made to Mrs Clinton !