Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[TCups]

can someone please explain what is producing this so called neutron ray that's been seen (sorry detected)? There was the mention of 1.5km, so I can only assume that it's been detected 1.5km distance from the plant, in a certain direction?

Artax:
I am not the best to answer, but I will give it a try, but I can only do so in a very basic way.

1) The elements in the core's fuel rods are neutron emitters. Neutrons, atomic mass 1, charge 0, are heavy but uncharged subatomic particles that come from the decay of U235 and Plutonium at high speed.

2) If the speed of the neutrons emitted are "moderated", slowed, as by water or graphite in a reactor core, then the the slowed ("thermal") neutron from one nucleus is more likely to hit or be captured by an adjacent nucleus, resulting in fission of the adjacent nucleus + energy + more neutrons.

3) If the emission of neutrons is sufficiently abundant, moderated to improve the chances of interaction with adjacent nuclei in the fuel, and the average "density" of the surrounding fissionable nuclei in the "fuel" - uranium, plutonium is sufficient, then a sustained nuclear reaction occurs and lots of heat is generated in the reactor core.

4) Boron among other substances, absorbs neutrons without undergoing fission, and therefor tends to slow the rate of emission of neutrons available for the chain reaction and controls the chain reaction. Control rods are neutron absorbers.

5) Unlike gamma radiation (very high energy photons, above the energy of the x-ray spectrum that penetrate all but the thickest shielding ), neutrons emitted from radioactive fuel are relatively easy to stop with shielding of moderate thickness. Even some plastics can do the job.

6) Detection of a "neutron beam" outside of the reactor would imply, I believe, elements in the nuclear fuel rods outside of the intact containment of the reactor vessel, or of the SFP, emitting "fast" neutrons (since they fuel was not surrounded by moderators) and therefore, potentially a much bigger problem.

7) It has not been confirmed that neutron radiation has been measured at the plant gates. In fact, one "reported" measurement of neutron radiation at or near the plant gates was a negative number (validity?). The point of measurement for the "neutron beam" was, in one source, reported to be at 1.5K from the site, and at a relatively low level, I believe.

 

[DrDu]

Sorry, i forgot to put the hyperlink for the source document, here it is (I edited the post to add it):

http://www.irsn.fr/FR/Actualites_pr...Seisme-Japon_Point-situation-24032011-08h.pdf

All the daily reports can be accessed from here:
http://www.irsn.fr/FR/Actualites_presse/Actualites/Pages/201103_situation_au_japon.aspx#1

According to the German society for reactor savety (GRS), the JAIP announced at 10 o' clock (the statement from France was at 8 o' clock) that the containment in Nr 3 is undamaged.
http://www.grs.de/sites/default/files/UE-STC-Stand_1100_240311_0.pdf

 

[Borek]

It's been a long, long time since I even thought about Ksp (?) - solubility constants in water. But do I remember correctly that CaCO₃ is less soluble in warm water than in cold?

Yes:

K<sub>sp[/sup] vs temperature in K

or

log_{10}(K_{sp}) = -1228.732-0.299440T+\frac{35512.75}T+485.818 log_{10}(T)</sub>

 

[jlduh]

What are the other confirmation, please ?

Well I should have written one more element that make us suspect that it is in direct contact with environment (let's be scientific ;o)).

Well i was thinking to the IRSN reports that is mentioned, the high readings around the reactor 3 (map) but also to my opinion the way this thing exploded the 14th of MArch.

I want to mention that some medias here question the integrity of this confinement since several days:

http://sciencepourvousetmoi.blogs.nouvelobs.com/archive/2011/03/23/fukushima-suite-16-uranium-et-transuraniens.html
http://sciencepourvousetmoi.blogs.n...-le-coeur-du-reacteur-n-3-est-il-a-l-air.html

but it 's not the vast majority (not a big title yet). The Lybian intervention focuses here a lot of the news...

It will be interesting to see how the IRSN reports with these new points are interpreted and translated into the medias here. But, independently to the fact that this option -reactor n°3 leaking since the explosion- proves to be true or not, i think that clearly this would be a tough news to release and explain to the public, especially in France because of the MOX/Areva stuff around this reactor...

 

[Borek]

Important smoke production has been observed. IRSN is evaluating the potential causes for confinement damages on reactor n°3. One hypothesis reviewed by IRSN is the possibility of the rupture of the reactor vessel followed by an interaction between the corium and the concrete at the bottom of the confinement well

That would mean very high levels of radioactivity being ejected, from my understanding so far these have been not reported.

 

[artax]

this site has some glaring omissions!

http://www.bousai.ne.jp/eng/index.html

Wonder what 'under survey' could mean, they're looking into it!

All over the page it boasts about why the site is there and the data collected... for nuclear safety, now... when the data actually means something it's covered up!

bloody ridiculous!
(oh cheers for that TCups!)

 

[TCups]

this site has some glaring omissions!

Wonder what 'under survey' could mean, they're looking into it!

All over the page it boasts about why the site is there and the data collected... for nuclear safety, now... when the data actually means something it's covered up!

bloody ridiculous!

Let's not be too critical of what is actually being done there, and what has been measured and reported. Remember that we are sitting safely in front of our computers, "speculating", not on site, in a very complicated and dynamic situation, trying to compile and report data accurately, in a section of a country that has been devastated by a quake and tsunami.

 

[|Fred]

DrDu, as I stated, French made some speculation base of some figure they read at 8, JAIP made some speculation of figure read at 11..

and I can give you the latest data even before they get published by NISA as the press conference just finished...

http://twitdoc.com/upload/sekizaiten/03242140no4.pdf

UNIT3 , temps @ nozzle are up at 65,6° / 155,7°
Pression in the RCV are 0.139MPa and 0MPa
Pression in the PCV is 0.107 MPa

this site has some glaring omissions!
bloody ridiculous!

the measurement are available else where but it's in Japanese

I want to mention that some medias here question the integrity of this confinement since several days:

What kind of credit can you give to someone who present IRSN speculation as hard evidence, and then base her own speculate on top of those dismissing very basic physics and availables data as she see fit ?

 

[|Fred]

Some pictures of the plant taken from the ground
http://www.meti.go.jp/press/20110324006/20110324006-5.pdf


Purely educated guess on my part: schematic Blue Print of the turbine block and location where the workers got contaminated
http://www.meti.go.jp/press/20110324006/20110324006-4.pdf

again educated guess: HPCP = High Pressure Condensate Pump

 

[83729780]

a couple of simple questions:

1) What is the likely concentration of boric acid in the coolant water?

2) What is the boiling point of brine + boric acid at said concentration?

 

[jlduh]

UNIT3 , temps @ nozzle are up at 65,6° / 155,7°
Pression in the RCV are 0.139MPa and 0MPa
Pression in the PCV is 0.107 MPa

For you, what would mean a ZERO Mpa reading for the RCV? If these are absolute values, then is the measurement unit damaged? If they are relative pressure readings, then this is atmospheric pressure. In GRS reports, they always talk about absolute readings... so i guess this is the case here?

The fact is that this reactor has for whatever reasons pressures which seem to be well below the other ones (I'm not talking about the ones who are in cold state). This is not in contradiction with the hypothesis of a failed confinement, even this doesn't prove either for sure that there is a failed confinement. Do you agree with this statement?

EDIT: the reactor 2 has readings for the reactor vessel of 0,065 Mpa on your japanese doc FRED, which is 0,065 x 1 000 000 = 65 000 Pascals, so less than one atmosphere of course. So either some of these readings are screwed up, either these are relative pressures.

For your remark FRED concerning the "nouvel obs" article, i give no real credit, I'm just saying that some medias ask the question here. On the other hand, it is nor abnormal that medias in France also base their article on what IRSN is saying and writting (which will be proving true or false) because this is the reference organisation in France for the follow up of this kind of accident.

 

[AntonL]

I think this estimates the equivalent exposure of thyroid gland due to Iodine-131 if one stayed outdoors continuesly from 12 to 24 March

 

[fusefiz]

| http://nnsa.energy.gov/mediaroom/pressreleases/fukushimadata

Press Release
U.S. Department of Energy Releases Radiation Monitoring Data from Fukushima Area
Mar 22, 2011

Today the U.S. Department of Energy released data recorded from its Aerial Monitoring System as well as ground detectors deployed along with its Consequence Management Response Teams. The information has also been shared with the government of Japan as part of the United States’ ongoing efforts to support Japan with the recovery and response effort.

On March 15, 33 experts from the Department’s National Nuclear Security Administration (NNSA) arrived in Japan along with more than 17,200 pounds of equipment. After initial deployments at U.S. consulates and military installations in Japan, these teams have utilized their unique skills, expertise and equipment to help assess, survey, monitor and sample areas for radiation. The 33 team members joined another six DOE personnel already in Japan.

Since arriving in Japan, NNSA teams have collected and analyzed data gathered from more than 40 hours of flights aboard Department of Defense aircraft and thousands of ground monitoring points.

That data has been collected, analyzed and posted on the Department’s website at www.energy.gov/japan2011. Consistent with the President’s commitment to share important information related to health and safety with the public, the Department will seek to update the data posted on its website daily.


[Go here to download slide presentation, MS powerpoint format]
| http://blog.energy.gov/content/situation-japan/

An image someone pulled from the slide presentation:
| http://forums.arbitraryconstant.com/images/fukushima-radiation.png

[Doesn't look like I managed to show this image inline ... follow the link, reload if necessary.]

All measurements were below 30 mRem/hr. The slide presentation says that the NRC estimates that the averge US resident receives 71 mRem/hr (from all sources combined, I presume).

 

[TCups]

Some pictures of the plant taken from the ground
http://www.meti.go.jp/press/20110324006/20110324006-5.pdf


Purely educated guess on my part: schematic Blue Print of the turbine block and location where the workers got contaminated
http://www.meti.go.jp/press/20110324006/20110324006-4.pdf

again educated guess: HPCP = High Pressure Condensate Pump

Fred: From the annotations that are in the English alphabet, that would be my guess, too - T/B = Turbine Bldg D/G = Diesel Generator, maybe. But the scale doesn't fit, unless it is only part of the building plan. The structure circled in the lower right of the floor plan, as usual, caught my eye. I was wondering if it might have something to do with the hole in the roof of Bldg 3. Probably not.

 

[TCups]

| http://nnsa.energy.gov/mediaroom/pressreleases/fukushimadata

Press Release
U.S. Department of Energy Releases Radiation Monitoring Data from Fukushima Area
Mar 22, 2011

Today the U.S. Department of Energy released data recorded from its Aerial Monitoring System as well as ground detectors deployed along with its Consequence Management Response Teams. The information has also been shared with the government of Japan as part of the United States’ ongoing efforts to support Japan with the recovery and response effort.

On March 15, 33 experts from the Department’s National Nuclear Security Administration (NNSA) arrived in Japan along with more than 17,200 pounds of equipment. After initial deployments at U.S. consulates and military installations in Japan, these teams have utilized their unique skills, expertise and equipment to help assess, survey, monitor and sample areas for radiation. The 33 team members joined another six DOE personnel already in Japan.

Since arriving in Japan, NNSA teams have collected and analyzed data gathered from more than 40 hours of flights aboard Department of Defense aircraft and thousands of ground monitoring points.

That data has been collected, analyzed and posted on the Department’s website at www.energy.gov/japan2011. Consistent with the President’s commitment to share important information related to health and safety with the public, the Department will seek to update the data posted on its website daily.


[Go here to download slide presentation, MS powerpoint format]
| http://blog.energy.gov/content/situation-japan/

An image someone pulled from the slide presentation:
| http://forums.arbitraryconstant.com/images/fukushima-radiation.png

[Doesn't look like I managed to show this image inline ... follow the link, reload if necessary.]

All measurements were below 30 mRem/hr. The slide presentation says that the NRC estimates that the averge US resident receives 71 mRem/hr (from all sources combined, I presume).

fuzefiz: May I help? Here are the two pertinent slide images you reference.

 

[|Fred]

...

Hint
the arrow on top of the drawing indicate "sea" 海 in japanse
so you got it the wrong way round

 

[timeasterday]

Fred: From the annotations that are in the English alphabet, that would be my guess, too - T/B = Turbine Bldg D/G = Diesel Generator, maybe. But the scale doesn't fit, unless it is only part of the building plan. The structure circled in the lower right of the floor plan, as usual, caught my eye. I was wondering if it might have something to do with the hole in the roof of Bldg 3. Probably not.

The orientation of the floorplan is reversed, I believe, in the overlay photo you attached. There's an arrow with the character for "sea" pointing up. I don't read Japanese but I do know quite a bit of Chinese and there are a lot of the same characters used.

 

[jlduh]

My instinct just tells me that the circle at the bottom of the drawing could represent the torus of the reactor n°3.

Some drawings also can confirm what my instinct tells me:

Typical BWR Mark I
http://www.netimago.com/image_181784.html

Oyster Creek reactor (US):
To help understand the scale of what we are talking about with these reactors, just consider the relative size of item n°32 on this sketch, which is the entrance gate for personnel and tools inside the containment vessel
http://www.netimago.com/image_181785.html
An other picture that give a good idea of the size of these litlle nuclear cookers:

http://www.netimago.com/image_181791.html

(I'm not sure if this represents the steel confinement or the concrete around it). On this picture, the round hole above the torus is maybe the gate of item 32 (it seems to be around 4,5 meters diameter based on the size of guy on the left side).

 

[TCups]

REGARDING UNIT 3

As referenced above from this document:
http://www.grs.de/sites/default/files/UE-STC-Stand_1100_240311_0.pdf

and quoting, in part, from page 10 of the document:

"From 11:03 h until 13:20 h on 23-03-2011, 35 t of sea water were pumped into the fuel pool of Unit 3 via the pool cooling and purification system.

At 16:20 h (23-03-2011), black smoke emanated from the reactor building of Unit 3. Subsequently, the surrounding premises of Units 3 and 4 were evacuated as a precau- tion. However, the measured values of the reactor pressure vessel and of the contain- ment as well as radiation measurements by the measuring probes in the direct vicinity of the plant showed no significant changes.

The smoke development seemed to cease on 24-03-2011 at around 4:50 h.
At 5:35 h, sea water injection into the fuel pool via the pool water and purification sys- tem was resumed.

According to JAIF (24-03-2011, 10:00 h), the containment is not damaged. Sea water injection into the reactor pressure vessel is being continued.

INES classification by the authority
The event in Unit 3 was classified by the authority on 18-03-2011 as INES 5."

Emphasis added is my own.

Does "containment is not damaged" refer to the reactor vessel and primary containment, or the reactor vessel only, or the primary (dry wall) containment only? I wish the statement had been more precise.

I can see only 2 sources of high level radiation contamination that might come from Unit 3 -- the reactor core or the spent fuel pool (or both). If either the RV or the RV and the primary containment are intact, then could vented steam from Unit 3 RV account for the high level contamination on the ground? If not, then it seems it must have come from the SFP.

Is there any other conclusion that would explain the highest measured levels contamination on the ground (if that is the appropriate term to use) other than it coming from either the core or SFP? Perhaps water leakage from the water sprayed on the building?

Is the most likely (even if speculative) conclusion that there has been both damage to and scattering of at least part of the fuel rod contents of the SFP at Unit 3? I cannot see any other.

 

[|Fred]

[PLAIN]http://i.min.us/imry38.jpg

D/G = Diesel Generator, in line with the diesel tank.. makes sens

 

[artax]

Well thank god for GRS... who are they? German?

That's such a relief to see information put so succinctly that I actually understand and believe it.!
Finally sounds like they're getting to grips with the whole thing now, with actual coolant flowrates and sensible temperature readings.

time to chill a little!

 

[TCups]

Hint
the arrow on top of the drawing indicate "sea" 海 in japanse
so you got it the wrong way round

Thanks all for corrections. My Japanese is even worse than my French.

Corrected diagram of Steam Turbine Bldg 3 oriented to satellite photo (maybe).

 

[jlduh]

[PLAIN]http://i.min.us/imry38.jpg

D/G = Diesel Generator, in line with the diesel tank.. makes sens

This nice insertion of the drawing makes sense to me also...

 

[TCups]

This nice insertion of the drawing makes sense to me also...

I am usually facile enough with images. It is the assessment of the additional data on radiation, and the actual design and operation of the BWR's where I am usually on shaky ground (excuse the quake reference).

Notice that in this diagram, if you look closely, there is a brave fellow in a white lab coat standing in the cutaway of the torus pool, which will give a good size reference.

Just for fun, I put his "clone" in the SFP. Wonder what his badge would read now.

 

[Reno Deano]

My instinct just tells me that the circle at the bottom of the drawing could represent the torus of the reactor n°3.

Some drawings also can confirm what my instinct tells me:

Typical BWR Mark I
http://www.netimago.com/image_181784.html

Oyster Creek reactor (US):
To help understand the scale of what we are talking about with these reactors, just consider the relative size of item n°32 on this sketch, which is the entrance gate for personnel and tools inside the containment vessel
http://www.netimago.com/image_181785.html



An other picture that give a good idea of the size of these litlle nuclear cookers:

http://www.netimago.com/image_181791.html

(I'm not sure if this represents the steel confinement or the concrete around it). On this picture, the round hole above the torus is maybe the gate of item 32 (it seems to be around 4,5 meters diameter based on the size of guy on the left side).

Shown (light bulb) is the inner steel liner of Primary Containment Structure (cement) that surrounds the Reactor Vessel.

 

[|Fred]

Breaking TCups news..
we are probably going to get answers (and likely more question) once I translated this:

News 3号機のプール温度 31度に Temperature Of the Unit 3 Pool 31° WTF ?
translating asap

edit:
According to a survey held the morning of the 24th by Self-Defense Force helicopter, the surface temperature of Fukushima Daiichi Nuclear Power Station spent fuel pool at Unit 3, dropped to 31 degrees.
The surface temperature of the building No. 4 to No. 1 T, droped 23° or was bellow 23° (not sure)

 

[jlduh]

Thanks Reno Deano for the confirmation, i thought it was steel but the appearance of the joints between the different part were strange to me like if it was joints between concrete parts. I imagine that due to its huge size this vessel is built on site like for a boat (welded on site)?

 

[TCups]

Breaking TCups news..
we are probably going to get answers (and likely more question) once I translated this:

News 3号機のプール温度 31度に Temperature Of the Unit 3 Pool 31° WTF ?
translating asap

edit:
According to a survey held the morning of the 24th by Self-Defense Force helicopter, the surface temperature of Fukushima Daiichi Nuclear Power Station spent fuel pool at Unit 3, dropped to 31 degrees.
The surface temperature of the building No. 4 to No. 1 T, droped 23° or was bellow 23° (not sure)

News Flash for Fred:

That tells us about what may be left in the SFP, but not necessarily what is no longer present in the SFP.

 

[Joe Neubarth]

can someone please explain what is producing this so called neutron ray that's been seen (sorry detected)? There was the mention of 1.5km, so I can only assume that it's been detected 1.5km distance from the plant, in a certain direction?

I think there is a problem with translation from Japanese to English. The Neutron "Ray" is probably the detection of a stray neutron. Many particles that decay radioactively spit out neutrons. It happens normally with radioactive particles in our rocks and soil, but is only infrequently detected unless you are in a Uranium mine.

Picking up a stray neutron is no big deal. Picking up many neutrons outside of the plant implies that delayed neutron precursors have been released to the outside of the plant or that Uranium or Plutonium from the fuel rods is present.

The additional information that we need to know is what is the strength of the ray? If it is just one neutron, we have almost nothing to worry about. Many neutrons and we have trouble.

 

[Joe Neubarth]

News Flash for Fred:

That tells us about what may be left in the SFP, but not necessarily what is no longer present in the SFP.

That is exactly what I thought. How did the Japanese get the reactor fuel plates to stop heating up?

 

[havemercy]

That is exactly what I thought. How did the Japanese get the reactor core to stop heating up the primary. It is too soon after shut down last week for it not to be heating the water and the vessel that contains that water. So the question that comes to mind is where is the core?
If it is underground, we have lots of trouble on our hands.

Sorry, but they are discussing the temperature of the pool and not of the reactor no ?

the drop of the temperature of the spent fuell pool, i guess, could not lead to the conclusion that the core is gone undergroud, isn't it ?

 

[TCups]

Sorry, but they are discussing the temperature of the pool and not of the reactor no ?

the drop of the temperature of the spent fuell pool, i guess, could not lead to the conclusion that the core is gone undergroud, isn't it ?

I will "guess" here, but it will be an educated guess. If the survey were done by a helicopter, then they might be using a laser interferometer and it would indeed measure the surface temperature of what it were shined on, in this case, the surface of the exposed SFP of unit 3. This would say nothing about 1) how deep the water is in the pool, or 2) if there were still fuel rods in the pool, or if there were still fuel rods in the pool, how many were still there. Also, Fred's "news fragment" doesn't indicate degrees in Fahrenheit or Celsius. I would hazard to "guess" degrees Celcius (ºC).

If they are all still there, then a temp reading of 23ºC is fantastic news. If all of the fissionable material has been blown out of the pool and (speculating wildly here) lies out and about on the ground or atop the building ruins, "beaming" neutrons and scattering gamma radiation, then there would be no reason for the pool to heat up. The real answer could be either or anything between those two ends of the possibility spectrum. Who knows.

 

[KateB]

I think there is a problem with translation from Japanese to English. The Neutron "Ray" is probably the detection of a stray neutron. Many particles that decay radioactively spit out neutrons. It happens normally with radioactive particles in our rocks and soil, but is only infrequently detected unless you are in a Uranium mine.

Picking up a stray neutron is no big deal. Picking up many neutrons outside of the plant implies that delayed neutron precursors have been released to the outside of the plant or that Uranium or Plutonium from the fuel rods is present.

The additional information that we need to know is what is the strength of the ray? If it is just one neutron, we have almost nothing to worry about. Many neutrons and we have trouble.

Here is what I had asked earlier re: the Neutron ray, as well as a person's excerpt of the press item describing said neutron ray- that also inquired above me (page 58 near the bottom) My knowledge of nuclear physics is rudimentary, but wouldn't neutron rays captured 1.5 km away, even such low readings, lead one to extrapolate that fissable material escaped the Suppression pools, and perhaps even containment?

From Reuters: "Radiation at the crippled Fukushima No.2 nuclear reactor was recorded at the highest level since the start of the crisis, Japan's nuclear safety agency said on Wednesday. An agency spokesman said 500 millisieverts per hour of radiation was measured at the No.2 unit on Wednesday. Engineers have been trying to fix the plant's cooling system after restoring lighting on Tuesday."

from Kyodo:

Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of the Fukushima Daiichi nuclear plant after it was crippled by the massive March 11 quake-tsunami disaster.

TEPCO, the operator of the nuclear plant, said the neutron beam measured about 1.5 kilometers southwest of the plant's No. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour and that this is not a dangerous level.

Not trying to flame the fire here. The rad levels are low and I'm hoping TEPCO continues to make progress controling the site but the neutron beam got me thinking about reactor integrity. Neutron beams are product of fission correct? Would this finding confirm reactor damage even if it's just a pin hole?

Y, 11:28 AM #928
KateB

KateB is Offline:
Posts: 1
Re: Japan Earthquake: nuclear plants
I was actually just going to query on the neutron beam reported 1.5 km from the Fukushima nuclear plant. As a Biochem undergrad, my knowledge of physics is rudimentary at best, but wouldn't a neutron beam offsite signify release of plutonium/uranium, and to extrapolate further, does this mean that one of the spent fuel pools blew fissable material "sky-high"? What are the implications of this news? I have been following this thread for a while, and this has been a great pool of knowledge and learning for me.

 

[|Fred]

I thought that emphasized strongly enough my surprise , rather than my joy.

Tepco had this information since this morning... and it was only released at 21:15
it is 2:45 am ... and we are still waiting for tepco press conference that has been delayed ... ( am I losing my science? )

NB: Japanese do not use barbaric units.. they use celcius )
Ps: They says that the temperature mesured on the 23th was 57°

 

[TCups]

I thought that emphasized strongly enough my surprise , rather than my joy.. hence my hint that this would raise more questions...

Tepco had this information since this morning... and it was only released at 21:15
it is 2:45 am ... and we are still waiting for tepco press conference that has been delayed ... ( am I losing my science? )

NB: Japanese do not use barbaric units.. they use celcius )

No, Fred -- keep us informed. Thanks.

 

[Pheesh]

At the bottom of this article from today..

http://english.kyodonews.jp/news/2011/03/80849.html

"The government said, meanwhile, it detected 2.54 million becquerels of iodine and 2.65 million becquerels of cesium, another radioactive substance, from weed leaves in the village of Iitate in Fukushima Prefecture about 40 km northwest from the nuclear plant, far above the provisional limits for food of 2,000 becquerels for iodine and 500 becquerels for cesium.

Abnormally high levels of these materials were also detected again in the sea near the plant, TEPCO said, warning the radiation levels in seawater may keep rising."

So...evac zone is 20km...these levels were detected 40km away, yet they are only 'considering' increasing the evac zone for convenience. Am I just misunderstanding the amounts quoted, they seem significant.

Thanks everyone for the information here, I have been quietly absorbing it.

 

[AntonL]

Corrected diagram of Steam Turbine Bldg 3 oriented to satellite photo (maybe).

the turbine building 3 is about 125 x 35 metres
the reactor building 3 is about 45 x 34 metres
reactor building to turbine building is about 25 metres apart
(source measured on google Earth 35:25:15N 141:02:02E)

Turbine building has an aspect ratio of 3:1Japanese plan has an aspect ratio of 2:1
I estimate it at 120 by 60 metres (based on door sizes, corridors)
Has no doors to the outside, so it is either a basement or an upper floor,
My guess upper floor as a ladies and gents can be identified. (just above the ng of Turbine Building)

My next guess - upperfloor of turbine building + connecting building between reactor and turbine

 

[Bodge]

Hi guys, 1st post!

Fascinating, terrifying stuff in this thread..

Here is a report by the US Department of Energy on blackout (no power supply) conditions in a Mark.1 G.E. BWR.

Note the timeline below:

Here is the full report.

http://www.osti.gov/bridge/servlets/purl/6124656-R8y05j/6124656.pdf

It states that all reactors should have ruptured their boilers within 8 hours.

Can we *really* have corium below ground? Where is the water table?

 

[Joe Neubarth]

the turbine building 3 is about 125 x 35 metres
the reactor building 3 is about 45 x 34 metres
reactor building to turbine building is about 25 metres apart
(source measured on google Earth 35:25:15N 141:02:02E)

Turbine building has an aspect ratio of 3:1Japanese plan has an aspect ratio of 2:1
I estimate it at 120 by 60 metres (based on door sizes, corridors)
Has no doors to the outside, so it is either a basement or an upper floor,
My guess upper floor as a ladies and gents can be identified. (just above the ng of Turbine Building)

My next guess - upperfloor of turbine building + connecting building between reactor and turbine

So all the diesel generators were on the ground floor? I have read that the diesel generators were washed away. So what was the extent of the damage to the main Turbine Generator? I am guessing that is what was in the middle of the schematic?

 

[Borek]

So all the diesel generators were on the ground floor? I have read that the diesel generators were washed away.

They were not. They started to work as expected and failed after about an hour.

 

[|Fred]

tepco conference just finished at 5 am !... ****

 

[Borek]

It states that all reactors should have ruptured their boilers within 8 hours.

If memory serves me well, cooling systems were working for about 9 hours - first on DG, then on batteries. I don't know how fast heat output from decay goes down, but for sure it is the strongest during first hours after scramming.

 

[Bodge]

If memory serves me well, cooling systems were working for about 9 hours - first on DG, then on batteries. I don't know how fast heat output from decay goes down, but for sure it is the strongest during first hours after scramming.

Thanks Borek

Still worrisome though

 

[|Fred]

Japanese are considering upgrading to INES 6, very confusing they were talking about radiation in terms of 27 Ci in the water on the power plant.
I'll wait for the official bulletin..

edit: mainly the press conference was minor statement from tepco indicating that, the worker went to a zone that was supose to have minor "air" radiation,when they arrived they found 13 cm of water , 2 of them where not prepare for that and did not have boots, (those 13 cm of water were not present the day before)
the radiation was in the range of 400mSv/h .
The press asked a lot of questions as for where does the watter come from etc.. Tepco does not know , one hypothesis that they are considering is a total meltdown of the rods (Spent Fuel ?) ..

we will get a better view tomorrow

 

[M. Bachmeier]

Here is what I had asked earlier re: the Neutron ray, as well as a person's excerpt of the press item describing said neutron ray- that also inquired above me (page 58 near the bottom) My knowledge of nuclear physics is rudimentary, but wouldn't neutron rays captured 1.5 km away, even such low readings, lead one to extrapolate that fissable material escaped the Suppression pools, and perhaps even containment?

From Reuters: "Radiation at the crippled Fukushima No.2 nuclear reactor was recorded at the highest level since the start of the crisis, Japan's nuclear safety agency said on Wednesday. An agency spokesman said 500 millisieverts per hour of radiation was measured at the No.2 unit on Wednesday. Engineers have been trying to fix the plant's cooling system after restoring lighting on Tuesday."

from Kyodo:

Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of the Fukushima Daiichi nuclear plant after it was crippled by the massive March 11 quake-tsunami disaster.

TEPCO, the operator of the nuclear plant, said the neutron beam measured about 1.5 kilometers southwest of the plant's No. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour and that this is not a dangerous level.

Not trying to flame the fire here. The rad levels are low and I'm hoping TEPCO continues to make progress controling the site but the neutron beam got me thinking about reactor integrity. Neutron beams are product of fission correct? Would this finding confirm reactor damage even if it's just a pin hole?

Y, 11:28 AM #928
KateB

KateB is Offline:
Posts: 1
Re: Japan Earthquake: nuclear plants
I was actually just going to query on the neutron beam reported 1.5 km from the Fukushima nuclear plant. As a Biochem undergrad, my knowledge of physics is rudimentary at best, but wouldn't a neutron beam offsite signify release of plutonium/uranium, and to extrapolate further, does this mean that one of the spent fuel pools blew fissable material "sky-high"? What are the implications of this news? I have been following this thread for a while, and this has been a great pool of knowledge and learning for me.

From post #22 https://www.physicsforums.com/showthread.php?t=481620

Re: Astronuc

"The matter of the neutron 'beam' or neutron radiation is of concern. It would seem to indicate loss of transuranics (fuel particles/fines) from the containment, which is not a good sign.
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[KateB]

From post #22 https://www.physicsforums.com/showthread.php?t=481620

Re: Astronuc

"The matter of the neutron 'beam' or neutron radiation is of concern. It would seem to indicate loss of transuranics (fuel particles/fines) from the containment, which is not a good sign.
__________________
Getting the 'right' answer is important, but understanding how to solve the problem (i.e. how you get the right answer) is just as important, if not more so.
Peace on Earth, and Goodwill to all Peoples, each day, every day, ad infinitum. - Joy to the World, Joy to You and Me. - Three Dog Night

The other 2005 Engineering Gurus: FredGarvin, Clausius2, Brewnog, Morbius, PerennialII, berkeman, arildno, Cliff_J, Geniere, minger

Raspberry Jam Delta-V - Joe Satriani"

Thank you. That is what I was concerned about. I appreciate the reply, It didn't occur to me to check other threads. I know speculation is not encouraged here, but perhaps someone could posit an educated guess as to the implications of transuranics escaping containment, and most especially if they had come from the Hydrogen explosion at No. 3 that rendered the building? I realize this hinders the effort at containment, but my question centers more on what the best and worst outcome regarding the possible escape of these particles could mean, mostly in the long term, as I know the half lives of these isotopes can range from multiple thousand to billions of years. I remember hearing a scientist say that the "fallout" from an atomic bomb was "safer" (which I realize is a ludicrous word to use in any discussion on large radioactive releases and/or bombs) than the slow fission and continued presence of transuranics within the environment. Is there a plausible way to recover any of these materials from the environment, IF there is indeed any release, or will an extended area have to be abandoned for...an eternity in human foresight? Thanks in advance.

 

[Bodge]

tepco conference just finished at 5 am !... ****

Anything to report?

 

[Joe Neubarth]

They were not. They started to work as expected and failed after about an hour.

They failed about thirty minutes after the Earthquake (and reactor Scram) because they no longer were there.

 

[Joe Neubarth]

__________________
Getting the 'right' answer is important, but understanding how to solve the problem (i.e. how you get the right answer) is just as important, if not more so.
Peace on Earth, and Goodwill to all Peoples, each day, every day, ad infinitum. - Joy to the World, Joy to You and Me. - Three Dog Night

The other 2005 Engineering Gurus: FredGarvin, Clausius2, Brewnog, Morbius, PerennialII, berkeman, arildno, Cliff_J, Geniere, minger

Raspberry Jam Delta-V - Joe Satriani"

With ruptured fuel plates, a release of high pressure steam would carry some entrained solids with it. The question is how much?

 

[Reno Deano]

News Flash for Fred:

That tells us about what may be left in the SFP, but not necessarily what is no longer present in the SFP.

The fact that they can get into the plants and grounds around them indicate that there are no spent fuel rods from the SFPs laying about.