Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Astronuc]

Thanks.

I need help reading the acronyms page 9 of https://www.sfen.fr/content/download/30655/1616957/file/1-ICAPP_Omoto2.pdf :

EE ?
SAM ?
AMG ?
Rx ?

SAM = Severe Accident Mitigation
AMG probably = Accident Mitigation Guide/Guideline/Guidance

Rx = Reactor, R/B = Reactor Building

EE could be emergency electrical or emergency equipment.

Acronyms can have multiple meanings, so context is important.

 

[bytepirate]

I never know what to think about CAMS readings.

But I can say that when I look back at the reactor 1 drywell CAMS readings I noted in the past, I have just one sensors data for the date range march 20th->april 8th, and it was yoyoing around the 30-50 range over this time, tending to be towards the lower end of this range as time went on. Then it suddenly went up to 100 on the 8th, then back down to 68.3 later on the 8th april. Then no more data was published from unit 1 D/W CAMS all the way until 17th may where we get 2 sensors readings ever since, one of which is usually well below 1 and the other which darts around from either 25-35 or sometimes leaps to 200 or more.

Over the same period S/C CAMS readings for unit 1 were available continually and tended to behave themselves more. Starting off with just one sensor on march 20th, started at 40 and decreased steadily to as low as 8 on april 6th. Bumped back up to 12.9 on april 7th before continuing its decline, down to 6.67 by april 17th. At this time it was joined by a second reading from the S/C, one that was lower at just over 1. By may there was less disagreement between both sensors, and they are both down to around 1 right now.

OK from that I could say that both S/C and D/W readings suggest something happened around april 7th-8th but I could not say what, though I seem to recall some earthquake around this period has ben discussed on this thread in the past weeks. I have forgotten whether there are any similar signs at other reactors, nor whether there was much of interest to be seen from the rather limited CAMS data from earlier on pre march 20th.

there is more data here (until 4/24): http://www.tepco.co.jp/nu/fukushima-np/f1/images/syusei_level_pr_data_1u.pdf (download as csv as well from this page: http://www.tepco.co.jp/nu/fukushima-np/)

i have attached a diagram of the D/W CAMS values (x is hours after scram, y is Sv/h).

EDIT: same diagrams for unit 2 and 3 look much 'smoother'

 

[SteveElbows]

there is more data here (until 4/24): http://www.tepco.co.jp/nu/fukushima-np/f1/images/syusei_level_pr_data_1u.pdf (download as csv as well from this page: http://www.tepco.co.jp/nu/fukushima-np/)

i have attached a diagram of the D/W CAMS values (x is hours after scram, y is Sv/h).

EDIT: same diagrams for unit 2 and 3 look much 'smoother'

Thanks. I had seen that data before, but I forgot to compare it to the original data that I had been recording manually from each status update.

By looking at both sets of data, it seems highly likely that the reason they originally stopped publishing unit 1 CAMS for the drywell after April 8th is not just because it spiked upwards and then wobbled all over the place, but because they got the 2nd sensor working at this time and it completely disagrees with what the other sensor was saying, by quite some orders of magnitude. I am not really sure why they started showing it on the overall status updates again as of may 17th, because the 2 sensors still disagree a lot.

 

[jlduh]

A nice computer animation of the Ocean pollution data from March 11th to May 21st :

Yes, and Two other ones for the evacuation zone outside of the 20 kms round zone (i guess it is based on SPEEDI data?):

http://www.youtube.com/watch?v=AavVDd1SmLQ&feature=related

http://www.youtube.com/watch?v=K4JzZGr5fwA&feature=related

 

[jlduh]

i apologize if this has been posted earlier. below links to 3 presentations from the icapp meeting special japan session.

https://www.sfen.fr/content/download/30655/1616957/file/1-ICAPP_Omoto2.pdf
https://www.sfen.fr/content/download/30419/1606950/file/2-ICAPP Fukushima Accident_Masui.pdf
https://www.sfen.fr/content/download/30420/1606953/file/3-ICAPP-0503P_Sato.pdf

source:
https://www.sfen.fr/ICAPP-11

Hi, thanks for the infos. I just wanted to mention that SFEN is acronym for Société Française d'Energie Nucleaire and is a french association which is a pro nuclear lobby . I know that because I've been personnally a member of this association... a long time ago!

I just wanted to let you know this because some of the conclusions may be not only "scientifically neutral"

 

[jlduh]

Meltdowns also at No.2, No.3 reactors
http://www3.nhk.or.jp/daily/english/24_16.html


Regarding the cooling of reactor 3: The 21 m³/h cooling water showing no added benefit was soon reduced to 18 m³/h being pumped into unit 3 and temperatures remaining well above 100^oC proves that most of the water does not even touch the molten core at the bottom of the reactor.

[PLAIN]http://k.min.us/ic1VA0.JPG

The huge amount of cooling water flowing past the core and the onwards to the environment (outside containment) adds to a further problem, Tepco have given notice that pumping away the trench water may soon stop as they have nowhere to store this water. They have pumped this water into the basements of the radioactive waste treatment buildings - but these basements are now nearly full. http://www3.nhk.or.jp/daily/english/23_25.html

As i said earlier, I'm afraid that the ultimate containment will be... the ocean.

Time is running...
Contaminated water is flowing...

 

[htf]

That's not that simple. Images are stored in compressed formats, so bit flips will change not just single pixels, they will break huge parts of the image (assuming file will be still readable).

You are right! So we should ask Tepco whether they observed any corrupted pictures.

 

[jlduh]

I just wanted to mention here this post from andybwell on an other thread:

https://www.physicsforums.com/showpost.php?p=3317685&postcount=106

Well, at the beginning of Gunderson's video above, he is saying :we know that n°1 reactor was already in course of meltdown and the containment was leaking before tsunami hit...

Is this supported by some statements or data or facts?

By the way, how would you describe the defects he is showing (holes, cracks, etc.)?

Personnaly, threatening may be an adequate word.

 

[AntonL]

Meltdowns also at No.2, No.3 reactors
http://www3.nhk.or.jp/daily/english/24_16.html

Most of the fuel is thought to have melted down and collected at the bottom of the reactor pressure vessel by 8 PM on March 15th. That's about 101 hours, or 4 days, after the earthquake

However, if they study the CAMS data http://k.min.us/ilrLwi.pdf" then they would note a spike in the readings between 13:00 and 15:25 on 15 March which would make the event even a couple of hours earlier, - a nice correlation between a theoretical study and actual field readings.

 

[AntonL]

I just wanted to mention here this post from andybwell on an other thread:

https://www.physicsforums.com/showpost.php?p=3317685&postcount=106

Well, at the beginning of Gunderson's video above, he is saying :we know that n°1 reactor was already in course of meltdown and the containment was leaking before tsunami hit...

Is this supported by some statements or data or facts?

some facts:
1. Reactor http://search.japantimes.co.jp/cgi-bin/nn20110517x1.html" after the quake and before the tsunami (Tepco should publish their official findings regarding this soon as instructed by NISA)

2. http://search.japantimes.co.jp/cgi-bin/nn20110516a3.html" at unit 1 well before the explosion indicating a possible breach in containment caused by earthquake.

So for a change, Gunderson statements are (part) true.

 

[Jorge Stolfi]

That's not that simple. Images are stored in compressed formats, so bit flips will change not just single pixels, they will break huge parts of the image (assuming file will be still readable).

Indeed, I get a sample of that from my satellite TV whenever a storm gets between the sat and the antenna.

Penetrating radiation should flip bits at random in every consumer-grade digital circuir --- not just in the image sensor, but also in the compression chips and in the interfacing processor.

In the first T-hawk videos, whenever the drone was getting too close to interesting spots --- such as the #4 SFP, or the service floor of #3 --- the image would dissolve into compression chaos, and I had the impression that the drone would then back away. I thought it could be bad reception perhaps due to all that rebar shielding the signal. But perhaps radiation was to blame?

 

[Giordano]

I have two questions.

A few weeks ago we saw estimations of total amount av radioactive materials emitted to the atmosphere made by NSC and I think Tepco. Should these estimations be updated now since we since then now know there has been a meltdown in #1, #2, and #3?

Has anyone made an estimation yet of the total amount of radioactive material emitted directly to the sea?

Thanks.

 

[clancy688]

A few weeks ago we saw estimations of total amount av radioactive materials emitted to the atmosphere made by NSC and I think Tepco. Should these estimations be updated now since we since then now know there has been a meltdown in #1, #2, and #3?

AFAIK these estimates didn't care the slightest about what was going on in the NPP. Whether there was a core melting down or Osama bin Laden throwing with spent fuel, it wasn't of concern.
They only measured the radiocativity in the air and made estimates with spread and dilution how much was probably released during the course of the accident.

Has anyone made an estimation yet of the total amount of radioactive material emitted directly to the sea?

TEPCO did it for one leak.

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110421e2.pdf

But nobody has any idea how much contaminated water really escaped.

 

[ascot317]

http://ex-skf.blogspot.com/2011/05/mainichi-english-agency-gears-up-to.html

Wait... what? Oo

Exactly my thought... and... "How?"

How is it technically possible to let this happen??

And... "Let's cool it with seawater" (yes, that's sarcasm).

 

[etudiant]

Exactly my thought... and... "How?"

How is it technically possible to let this happen??

And... "Let's cool it with seawater" (yes, that's sarcasm).

Sarcasm seems uncalled for.
When that decision was made, quite reluctantly and perhaps too late, there was no other way to try to cool the reactors.
We should always remember the site is in the middle of a disaster zone, with 25,000 people dead and many times that number homeless.

 

[ascot317]

Sarcasm seems uncalled for.
When that decision was made, quite reluctantly and perhaps too late, there was no other way to try to cool the reactors.
We should always remember the site is in the middle of a disaster zone, with 25,000 people dead and many times that number homeless.

I'm referring (see the link I quoted in my post) to the sodium-cooled fast breeder that apparently swallowed a 3.3 tonne loading machine they now can't retrieve. Just a few months after the first restart in >15 years after the last incident there (15 years that included a technical overhaul). They apparently can't let it run for much more than a year without something terrible happening. It's just radioactive sodium and MOx-fuel.

 

[andybwell]

None taken I was simply defending my idea that the core shroud could fit through a hole of that size in response to your picture that suggested it was impossible due to physical size constraints. There are good arguments against that being the actual ingress point for the new core shroud, but, "It won't fit," isn't one of them.


My central contention in all this is that the green box/framework/hole thing could have had something to do with the core shroud replacement project, not that that spot was definitively the location of core shroud ingress. I really don't care how they got them in and out of the building. The core shroud replacement job is much more than a routine refueling outage. There must be (literally) tons of extra equipment and tools needed above and beyond what's normally in the reactor building, and maybe whatever was happening on the low roof in the SE corner of the building was in a support role for all that extra stuff.

The explosions in buildings 1 and 3 have been attributed to a buildup of H2 gas that escaped from primary containments. The etiology of the building 4 explosion must have been very different. Did the green box/framework/hole apparition and/or the core shroud replacement work contribute to the explosion of building 4? I think we're no closer to answering that question than we were on 12 March.

Could the explosion in building 3 have been within the reactor core, and blown its lid off so that it is now exposed to the air?

 

[~kujala~]

Funny, it was indeed the cooling that caused the cooling problems at #1 right after the earthquake but not the isolation condenser being too weak but too powerful. This is the impression one gets when reading The Daily Yomiuri:

The TEPCO operational manual says the reactor's temperature should not be allowed to fall at a rate of 55 C per hour or more, and isolation condenser operations should be adjusted to prevent such an occurrence.

TEPCO said its workers halted the cooling system because it had caused excessive cooling, with the reactor temperature falling more than 100 C in the time the condenser had been operating.

http://www.yomiuri.co.jp/dy/national/T110524005786.htm

 

[etudiant]

I'm referring (see the link I quoted in my post) to the sodium-cooled fast breeder that apparently swallowed a 3.3 tonne loading machine they now can't retrieve. Just a few months after the first restart in >15 years after the last incident there (15 years that included a technical overhaul). They apparently can't let it run for much more than a year without something terrible happening. It's just radioactive sodium and MOx-fuel.

The Monju accident is a stunner, no doubt about it.
Considering that this reactor had a major breakdown before, with sodium leaking and pooling everywhere, it is almost incomprehensible that the operations would again be mismanaged so badly.
Given that the breeder is Japans best hope for energy independence, one would have hoped for better.

 

[SteveElbows]

Results of air sampling from above reactors 1 & 4 is out, not sure I've seen this mentioned here till now?

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110524_01-e.pdf

Numbers too low to cause much excitement? Not that these reactors were looking like the best candidates for giving off the largest releases, and I am not entirely sure about TEPCOs choice of sampling point above each building either. Whats located in the corner of unit one that they chose?

(photos showing sampling locations here http://www.tepco.co.jp/en/news/110311/index-e.html )

 

[Borek]

I see we are back to armchair blaming TEPCO management and engineers. Please move this part of the discussion elsewhere.

Just in case you all forgot:

Do not condemn until you have walked in their shoes.

 

[maddog1964]

I see we are back to armchair blaming TEPCO management and engineers. Please move this part of the discussion elsewhere.

Just in case you all forgot:

Thank you.

 

[andybwell]

Results of air sampling from above reactors 1 & 4 is out, not sure I've seen this mentioned here till now?

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110524_01-e.pdf

Numbers too low to cause much excitement? Not that these reactors were looking like the best candidates for giving off the largest releases, and I am not entirely sure about TEPCOs choice of sampling point above each building either. Whats located in the corner of unit one that they chose?

(photos showing sampling locations here http://www.tepco.co.jp/en/news/110311/index-e.html )

I am reading info stating almost 200 sieverts per hour at reactor 1. Is this believable?

http://webcache.googleusercontent.com/search?q=cache:qp1hOuKX1zgJ:atmc.jp/plant/rad/+%3Ca%20href=

 

[andybwell]

I am reading info stating almost 200 sieverts per hour at reactor 1. Is this believable?

http://webcache.googleusercontent.com/search?q=cache:qp1hOuKX1zgJ:atmc.jp/plant/rad/+%3Ca%20href=

My apologies, I did not see the "instrument failure" next to graph.

 

[jmz007]

I am reading info stating almost 200 sieverts per hour at reactor 1. Is this believable?

http://webcache.googleusercontent.com/search?q=cache:qp1hOuKX1zgJ:atmc.jp/plant/rad/+%3Ca%20href=

you read it right, but not completely. it says "instrument failure" in the header.

.edit: I'm slow..

 

[elektrownik]

My apologies, I did not see the "instrument failure" next to graph.

I can't agree with this, on tepco data there is no info about sensor damage, and there is more data, look on tepco data not on this site, some days ago it show 5000Sv in unit 4... tepco data is first and best information source...

 

[ottomane]

"instrument failure" is only found in these documents (what source is this?), not in the original tepco datasets.

 

[Atomfritz]

some days ago it show 5000Sv in unit 4... tepco data is first and best information source...

aaaawww... 5000 Sv? where exactly? link pls :)

 

[MiceAndMen]

Could the explosion in building 3 have been within the reactor core, and blown its lid off so that it is now exposed to the air?

Not likely.

 

[Uagrepus]

The original photo with "fried pixels" near Unit 2 is in Tepco's press releases:

http://www.tepco.co.jp/en/news/110311/images/110412_1f_tsunami_6.jpg

The Exif-info of this picture shows the used camera was a Sony DSC-P32. Some people mod this model by replacing the infrared filter glass with normal glass in front of the CCD-sensor:
here ...
http://www.pixcontroller.com/forums/index.php?act=attach&type=post&id=3528
or ...
http://www.pixcontroller.com/forums/index.php?act=attach&type=post&id=3564

The original picture is from this photo-session ...

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e9.pdf

and the single photos are linked on Tepcos site ...

http://www.tepco.co.jp/en/news/110311/index-e.html
... beginning with date "2011.4.11 (Fukushima DaiIchi Nuclear Power Station)".

Alas none of the other photos that day were shot with this Sony DSC-P32 (Panasonic, Olympus etc.), so there is no reference, whether the Sony cam had these pixel anomalies before or after that take :-/

Wasn't lovely bionerd23 using a Sony CCD in her video?
http://www.youtube.com/all_comments?v=jFNvYA7731o

 

[clancy688]

Some new informations by EX-SKF again.

http://ex-skf.blogspot.com/2011/05/containment-vessels-of-reactors-1-2-3.html

http://ex-skf.blogspot.com/2011/05/multiple-10-centimeter-holes-in-reactor.html

Someone at Yomiuri Shinbun who was made to read the TEPCO's report to the Nuclear and Industrial Safety Agency (NISA), the government overseer, found this bit of information in the main report (225 pages, in Japanese; English translation is on-going at TEPCO): Containment Vessels were damaged within 24 hours of the quake.

According to the Mainichi article, TEPCO came to the conclusion of multiple 10-centimeter holes in the Reactor 2 Containment Vessel and one 7-centimeter hole in the Reactor 1 Containment Vessel from the analysis of the pressure data.

I'm really anticipating the translated version of this 225 page report. But this will take a while. One month according to TEPCO - http://www.tepco.co.jp/en/press/corp-com/release/11052412-e.html

Still, there are two new releases.

Summary of the analysis - http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110524e13.pdf
Status of reactor cores 2 and 3 - http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110524e14.pdf

Typical TEPCO humor again...

Seeing that cooling by water injection is continued, we don't think it will develop into the serious situation that leads to a large-scale emission of radioactive materials.

To sum it up, we have a INES level 7 radioactivity release, we have 10% of Chernobyl emissions, the whole pacific is now a nuclear waste storage facility and probably half of Fukushima prefecture is an exclusion zone, but that still is not, I quote, a "serious situation" with "large-scale emission of radioactive materials".

 

[andybwell]

"instrument failure" is only found in these documents (what source is this?), not in the original tepco datasets.

It appears to be from a Company called ATMC

http://www.atmc.co.jp/company.html (I translate it using Google Chrome)

 

[jlduh]

Some new informations by EX-SKF again.

http://ex-skf.blogspot.com/2011/05/containment-vessels-of-reactors-1-2-3.html

http://ex-skf.blogspot.com/2011/05/multiple-10-centimeter-holes-in-reactor.htmlI'm really anticipating the translated version of this 225 page report. But this will take a while. One month according to TEPCO - http://www.tepco.co.jp/en/press/corp-com/release/11052412-e.html

Still, there are two new releases.

Summary of the analysis - http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110524e13.pdf
Status of reactor cores 2 and 3 - http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110524e14.pdf

This article is again very interesting and i second all the comments and remarks.

http://ex-skf.blogspot.com/2011/05/containment-vessels-of-reactors-1-2-3.html

It's been revealed that the steel Containment Vessels of the Reactors 1, 2 and 3 that house the Reactor Pressure Vessels (RPV) may have been damaged within 24 hours after the earthquake on March 11, according to the detailed analysis of the core meltdown at Fukushima I Nuclear Power Plant by TEPCO.

Pfff, they start to become very predictable at Tepco: just read the last sentence of my post moved here

https://www.physicsforums.com/showpost.php?p=3320250&postcount=171

A little bit more time will tell what did damage these vessels, but earthquake is a good candidate.

 

[SteveElbows]

A little bit more time will tell what did damage these vessels, but earthquake is a good candidate.

Im not convinced that it is. If they are basing containment damage estimates on pressure readings, then have to look at the time the pressure readings that are indicative of containment failure occur, and we would expect this to be quite a long time after the earthquake itself from everything I remember of pressure data at all the reactors..

I do not rule out the possibility that the earthquake damaged some stuff, but any signs of this remain elusive, and so much happened within a short space of time. Its fairly hard to separate earthquake damage, tsunami damage, human error and loss of power as factors which influenced events of the first few hours.

At this point I will assume that damage to containment etc was result of conditions inside the reactors once sufficient cooling & water levels were lost, because almost all of the data we have that shows bad stuff happening, either to fuel, reactor vessel or containment, is from later on.

 

[rowmag]

[Posted in other thread, copying here.]

From this morning's paper:

http://www.asahi.com/special/10005/TKY201105240733.html

Summary: Unit 3 ECCS (Emergency Core Cooling System?) may have been damaged by the earthquake, before the tsunami arrived.
(According to analysis released by TEPCO on the 24th.)

Add: I guess the analysis is the report EX-SKF was talking about: http://www.tepco.co.jp/cc/press/betu11_j/images/110524a.pdf
Ooh, this looks juicy. Good bedtime reading.