Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
Borek
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#10405
Jun30-11, 05:49 PM
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Quote Quote by causeceleb View Post
but i still don't get it. i thought one becquerel was one disintegration;

how can i have .000003 disintegration (counts per second)
What about one disintegration per 300000 seconds per mL?
causeceleb
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#10406
Jun30-11, 05:51 PM
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Quote Quote by causeceleb View Post
here's the correction:

2.3 micro becquerels (counts per sec.) per cubic centimeter in the air for Iodine-131

9.5 micro becquerels (counts per sec.) per cubic centimeter in the air for Cesium-134

9.3 micro becquerels (counts per sec.) per cubic centimeter in the air for Cesium-137
Quote Quote by Borek View Post
What about one disintegration per 300000 seconds per mL?
then you are saying that TEPCO is saying that there is next to zero radioactivity (these
three isotopes) at the main gate?
clancy688
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#10407
Jun30-11, 06:01 PM
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Quote Quote by causeceleb View Post
but i still don't get it. i thought one becquerel was one disintegration (1 count per sec);
how can i have .000003 of a disintegration (.000003 counts per second)?
what is a 3 millionth of a disintigration?
what is a 3 millionth of a count per second?
It is my understanding that such measurements are taken over a larger area than 1 cm and over a bigger timeframe than one second.

So for example you take 1 m air and count all disintegrations over a period of twelve hours. Afterwards you recalculate those results into easier to understand numbers, e.g. Bq/cm3.

What you finally get is more or less a disintegration probability. The probability that there'll be a disintegration in one cm air is 0.0003% every second.
Borek
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#10408
Jun30-11, 06:03 PM
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Quote Quote by causeceleb View Post
then you are saying that TEPCO is saying that there is next to zero radioactivity (these three isotopes) at the main gate?
No, I am just explaining what the result means.
clancy688
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#10409
Jun30-11, 06:14 PM
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Quote Quote by SteveElbows View Post
The following document, which I have mentioned at least once before in this thread and which is in Japanese, seems to contain a wealth of information about how they estimate contamination, far more than we usually get. Its from an NSC meeting (meeting 31). Computer translation does not do a perfect job of revealing the details in their full glory, but give it a try and you should at least see what I mean. There are a few tables and charts there too which require almost no translation to understand. And the one on the very last page shows a timeline of release magnitude which really helps to get a sense of the picture they have established when collecting data and doing their analysis of what happened.

http://www.nsc.go.jp/anzen/shidai/ge...1/siryo4-2.pdf
Big thanks! The graph is interesting indeed.

There was a MAJOR C137 release going on for at least one day between March 30th and 31st. 100 TBq/h, makes 2400 TBq C137. Converted value: 96.000 TBq, over 10% of the total number. That alone would be sufficient for an INES 7 classification. What happened that day?

Or is this a mistake on my part, did I read the chart wrong?

In case it's real: Then screw my previous comments about airborne releases and the number not rising anymore - in that case, those are wrong of course.
causeceleb
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#10410
Jun30-11, 06:21 PM
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Quote Quote by Borek View Post
No, I am just explaining what the result means.
well, i thought 9.5E-06 meant 9.5 times 10 to the minus 6, but
the whole thing just threw me for a loop.
thank you for helping me grab hold of reality :)
SteveElbows
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#10411
Jun30-11, 06:59 PM
P: 630
Quote Quote by elektrownik View Post
Yes but this new water injection system is almost the same as concrede pump, so this shouldnt act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushi...10630_03-e.pdf
Photos are interesting. Im pretty sure that some of the stuff seen is an off-white colour because earlier in June they sprayed the anti-scatter substance onto the roof of reactor 4. This could also be what the gunk around one of the photographed valves is, although I cannot be sure.

Good to see the gate between the fuel pool and the reactor well, good to see the reactor well full of water. I wonder if the water level will stay stable.

Do you care much now about the reported skimmer surge levels? To add to list of possibilities regarding what has changed, I suppose it is possible that gate between fuel pool & reactor well still had a leak, and now they have filled up the reactor well, water is not being lost from fuel pool so quickly, so less filling required? Anyway it seems that I was probably wrong to suggest that maybe they use the new water system on a more continuous basis, since I checked recent status reports and brief injections via this system have been reported in recent days.

Another possibility is that since completion of steel structural support under fuel pool, they feel they have more options available to them, perhaps they were avoiding certain things because of fear of structural failure. For example I dont think they started filling the reactor well & storage pit with water until the first phase of structural support work was done, but this could be a mere co-incidence of timing for all I know.
Bodge
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#10412
Jun30-11, 07:38 PM
P: 145
The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.


SteveElbows
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#10413
Jun30-11, 07:40 PM
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Quote Quote by clancy688 View Post
Big thanks! The graph is interesting indeed.

There was a MAJOR C137 release going on for at least one day between March 30th and 31st. 100 TBq/h, makes 2400 TBq C137. Converted value: 96.000 TBq, over 10% of the total number. That alone would be sufficient for an INES 7 classification. What happened that day?

Or is this a mistake on my part, did I read the chart wrong?

In case it's real: Then screw my previous comments about airborne releases and the number not rising anymore - in that case, those are wrong of course.
I dont think you are reading the chart wrong,but due to a lack of official narrative about air release events past the first week, I cannot really tell you what happened on that day, but I do intend to look into it further again sometime. It was the even higher magnitude release estimated for a time on March 15th that got most of my attention when I first found this document.

As for the number not rising significantly anymore, using computer translation of that NSC document Im fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I dont think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases dont make very much difference to the estimated total is still valid.
SteveElbows
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#10414
Jun30-11, 07:45 PM
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Quote Quote by Bodge View Post
The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.
I believe we still need to check for other factors which could cause spikes in such data. For example weather.
clancy688
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#10415
Jun30-11, 07:54 PM
P: 546
Quote Quote by SteveElbows View Post
Im fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I dont think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases dont make very much difference to the estimated total is still valid.
Well, there's a problem. On page 4 there's another chart showing exact values and time periods. I used it to calculate the whole C137 release (no time for I131, maybe tomorrow). Released Cesium (per hour) is (Release Rate / (1 + I/C Ratio)).
But I'm coming 2000 TBq short. NSC's estimate was a release of 12.000 TBq C137. I only get 10.000 using their numbers.
Oh, and the exact C137 release for March 30th-31st would be 1900 TBq (unconverted) or 75.000 TBq (converted).
Bioengineer01
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#10416
Jun30-11, 11:26 PM
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Quote Quote by SteveElbows View Post
I dont think you are reading the chart wrong,but due to a lack of official narrative about air release events past the first week, I cannot really tell you what happened on that day, but I do intend to look into it further again sometime. It was the even higher magnitude release estimated for a time on March 15th that got most of my attention when I first found this document.

As for the number not rising significantly anymore, using computer translation of that NSC document Im fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I dont think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases dont make very much difference to the estimated total is still valid.
Did you guys look at the way the releases acknowledged by TEPCO in the document you mentioned are reflected in the CTBTO charts, posted before? Is it reasonable to back extrapolate from that and take a rough guess at newer non-reported releases at later dates from the peaks in the graphs? Am I making sense?
LabratSR
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#10417
Jul1-11, 12:48 AM
P: 173
I haven't seen this posted yet, sorry if it has been.

English Version of Timeline Released.

http://www.tepco.co.jp/en/press/corp.../110618e15.pdf
tsutsuji
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#10418
Jul1-11, 12:54 AM
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Quote Quote by tsutsuji View Post
The daily Kurion-Areva facility trouble :

http://sankei.jp.msn.com/affairs/new...2440037-n1.htm (and http://www.tepco.co.jp/en/nu/fukushi...10630_05-e.pdf ) : On 30 June the decontamination facility was stopped for flushing between 10:46 AM and 1:35 PM. The facility was restarted but after one hour it had to stop again because of an alarm signalling that gasses are unable to evacuate through the exhaust stack at the Areva facility.

http://www.nikkei.com/news/headline/...E39797E0E2E2E3 The facility started again at 6:50 PM (30 June).
http://mainichi.jp/select/jiken/news...40075000c.html the reason of the trouble was a mistake in the control of the water level in a tank. Although the water level must be set at 3% above the bottom when the facility is stopped and 30% when it is running, the facility had been started with the level still set at 3%.

http://www.nikkei.com/news/headline/...E39790E0E2E2E2 : from 1 July to 4 July, Tepco will be installing a new water tank whose purpose is to centralise the two water routes (the route from the filtrate tank, and the route from the water purification facility) that take water to the reactors. The new tank will have a 1000 ton capacity. On 1 July the cooling is switched back to the filtrate water tank. The new "buffer tank" is shown on the diagram at http://www.tepco.co.jp/nu/fukushima-...10701_02-j.pdf . At the same time, the PVC hoses will be changed to steel pipes.
MiceAndMen
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#10419
Jul1-11, 02:39 AM
P: 276
Quote Quote by elektrownik View Post
Yes but this new water injection system is almost the same as concrede pump, so this shouldnt act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushi...10630_03-e.pdf
Hallelujah we finally have an official TEPCO diagram for the refueling floor at unit 4. Very interesting pictures. How very strange to see the reactor well open to the sun and sky looking like a large swimming pool.
joewein
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#10420
Jul1-11, 02:46 AM
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Quote Quote by Bodge View Post
The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.


I find they show the exact opposite.

If fresh I-131 was produced by fission and released then one would expect levels to come back to the same levels in the first chart after every fission event, more or less. The fact that both the valleys and peaks of the iodine curves drift down in line with logarithmic decay indicates that no fresh I-131 is being produced. The ups and downs are probably mostly driven by weather conditions, such as changes in wind directions, rain, etc.

The second argument against ongoing fission is that the ratio of iodine to cesium is shifting just the way one would expect from decay. Cesium has been holding almost steady (with some random ups and downs) since later March, while iodine keeps falling (also with some ups and downs). That's precisely what one would expect in the absence of ongoing fission, given the different half lives (Cs-134: 2 y; Cs-137: 30 y; I-131: 8 d). If there were fresh releases from ongoing fission, the cesium and iodine curves would look a lot more alike than they do.
joewein
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#10421
Jul1-11, 04:03 AM
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Quote Quote by MiceAndMen View Post
Quote Quote by elektrownik View Post
Yes but this new water injection system is almost the same as concrede pump, so this shouldnt act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushi...10630_03-e.pdf
Hallelujah we finally have an official TEPCO diagram for the refueling floor at unit 4. Very interesting pictures. How very strange to see the reactor well open to the sun and sky looking like a large swimming pool.
I am attaching horizontal views of Fukushima 1 unit 1, looking north and looking west. Units 2-5 are somewhat different, but it should still be a useful reference.
Attached Thumbnails
daiichi-drawing.jpg  
causeceleb
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#10422
Jul1-11, 04:44 AM
P: 17
how can there be no new Iodine-131 when there is
800 tons of corium laying about all over the place
at Fukushima Daiichi?


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