Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Maxion]

Pic of the tsunami in the plant . Before and after .

That's Daiini, not Daiichi.

 

[jpquantin]

Confusion reigns in Kyodo,

http://english.kyodonews.jp/news/2011/04/84828.html"

BBC report has some errors.

Total Chernobyl radiation leakage was http://www.iaea.org/Publications/Magazines/Bulletin/Bull383/dreicer.html" between 1332 and 1847 peta-bq (10^15).

BBC reports of 630,000 tera-bq (10^12) per hour http://www.bbc.co.uk/news/world-asia-pacific-13045341" .

"The decision to raise the threat level was made after radiation of up to 630,000 terabequerels per hour had been estimated at the stricken plant for several hours.

That would classify the crisis at level seven on the International Nuclear and Radiological Event Scale (Ines).

It was not clear when that level had been reached. The level has subsequently dropped to less than one terabequerel an hour, reports said."​

They add:

"In comparison the Japanese government said the release from Chernobyl was 5.2 million terabecquerels."​

Chernobyl estimated in IAEA document: 1.332 - 1.847 10^18 bq.
Chernobyl for the Japanese government: 5.2 10^18 bq

Now 630,000 tera-bq per hour is 630 10^15 bq, or 0.63 10^18 bq. Several hours would mean at least 2, so they estimate minimal release to 1.26 10^18 bq. This is between a quarter and a full Chernobyl (in a few hours).

Kyodo http://english.kyodonews.jp/news/2011/04/84888.html" a TOTAL of 0.37 - 0.63 10^18 bq, which is between a tenth and a half Chernobyl.

 

[AntonL]

Confusion spreads ... Either this is not tera, or it is between a quarter and a full Chernobyl (in a few hours), or I've made an error in my maths (or I shouldn't try to understand amid distorted information).

extract from http://www.meti.go.jp/press/2011/04/20110412001/20110412001-1.pdf
[PLAIN]http://k.min.us/imDj6O.JPG

Col 1 - Fukushima NISA estimate
Col 2 - Fukushima Safety Commission estimate
Col 3 - Tschernobyl case

Row 1 = I-131 (a)
Row 2 = Cs-137
Row 3 = Cesium in terms of Idodine (b)
Row 4 = (a)+(b)

The column 3 figures for CS-137 an I-131 you should find in the Tschernobyl literature (upper limit)

 

[clancy688]

Confusion spreads ...

Total Chernobyl radiation leakage was http://www.iaea.org/Publications/Magazines/Bulletin/Bull383/dreicer.html" between 1332 and 1847 peta-bq (10^15).

That's the total activity based on all sources at time of the release. INES is using radioactivity numbers different...
The total discharge is calculated as an amount of I131 equivalence - you're basically taking a table from the INES-manual which gives you different factors for every released isotope. For example, C137 radioactivity release * 40 => equivalent radioactivity release for I131.

BBC reports of 630,000 tera-bq (10^12) per hour http://www.bbc.co.uk/news/world-asia-pacific-13045341" .

That's probably an error. NSC sets the total discharge of I131 and C137 in I131 equivalence at 630.000 Tbq.

http://www.nisa.meti.go.jp/english/files/en20110412-4.pdf

"In comparison the Japanese government said the release from Chernobyl was 5.2 million terabecquerels."​

INES manual tells us total amount of radioactivity release at Chernobyl in I131 equivalence is around 5.400.00 TBq. And in their INES 7 paper, NISA states, that the total amount of I131 and C137 released during Chernobyl is 5.2 * 10^18 Bq I131 equivalence:
Chernobyl I131 was 1.8 * 10^18 Bq and C137 was 8.5 * 10^16 Bq. Those are also the numbers I'm familiar with. And now (1 * 1.8 * 10 ^ 18) + (40 * 8.5 * 10^16) = 5.2 * 10^18 Bq

Chernobyl estimated in IAEA document: 1.332 - 1.847 10^18 bq.
Chernobyl for the Japanese government: 5.2 10^18 bq

I don't know from where you get your 1.332 - 1.847 * 10^18 numbers - I can't find them in your linked IAEO document. The link you provided us tells something about 2 EBq of I131, which's 2*10^18 -> 2000 * 10^15

 

[bytepirate]

Col 1 - Fukushima Nisa Estimte
Col 2 - Fukushima Dafety commision estimate
Col 3 - Tschernobyl case

Row 1 = I-131 (a)
Row 2 = Cs-137
Row 3 = Cesium in terms of Idodine (b)
Row 4 = (a)+(b)

available in english as well: http://www.nisa.meti.go.jp/english/files/en20110412-4.pdf

another question:
tepco is concerned, that the radiation may reach the chernobyl values.
http://english.kyodonews.jp/news/2011/04/84828.html

as the radiation currently leaks much slower than before, this would mean, that they expect/fear that the current situation lasts *for years* ?

 

[artax]

An interesting article providing some details of the first two days of the accident:

http://www.yomiuri.co.jp/dy/national/T110411004567.htm"

Fascinating reading that!... and it doesn't surprise me, TESCO seem to have dithered and been indecisive throughout this disaster.

 

[jpquantin]

AntonL, clancy688,

I wasn't aware of this iodine 131 equivalence. Thank you for clarifying!

 

[artax]

Just watched TEPCO new drone video and was going to post it but quality is so bad its worthless ! Pics to show bad quality ! I hope they have better shots that there not releasing . It does show steam still coming from Unit 3 spent fuel pool and reactor location . Looks like even more . Unit 4 steam or smoke coming from turbine facing side out of blowout in wall if you look close .

Can't agree more! Those drone videos are terrible. Like someone else said, US military totally wating money if that's the best they can do! A 300 dollar RC helicopter with a 200 dollar 12MP digital camera, (suspended on rubber bands for the vibration) and a 32GB sdcard would be far superior!

 

[Krikkosnack]

I have some questions ...

1) Only one microgram of plutonium can kill a man, so : Is it possible to measure the alpha and beta particles of a microgram of plutonium in the food? In other words : How the people of Japan can be protected now from nuclear pollution in food?

2) Normally We measure only the gamma ray from plutonium and uranium with the standard geiger counter?

3) Due to the type of Hydrogen explosion of reactor (different from Chernobyl), can we generate a list of all the isotopes that we will retrieves on power plant site?

 

[Bodge]

I don't see in the link where the sensor for bottom of RPV is showing readings in Unit 2 after 3-30-11 .

It was on the pdf, http://atmc.jp/plant/temperature/?n=2 shows 208.1C now

 

[Bodge]

I have some questions ...

1) Only one microgram of plutonium can kill a man, so : Is it possible to measure the alpha and beta particles of a microgram of plutonium in the food? In other words : How the people of Japan can be protected now from nuclear pollution in food?

2) Normally We measure only the gamma ray from plutonium and uranium with the standard geiger counter?

3) Due to the type of Hydrogen explosion of reactor (different from Chernobyl), can we generate a list of all the isotopes that we will retrieves on power plant site?

I want to know where all the Strontium is.

Are TEPCO only testing for certain isotopes?

 

[tsutsuji]

I don't see in the link where the sensor for bottom of RPV is showing readings in Unit 2 after 3-30-11 .

I attach the bottom of page 1 of http://www.meti.go.jp/press/2011/04/20110412002/20110412002-3.pdf

 

[clancy688]

Are TEPCO only testing for certain isotopes?

Only I131, Cs134 and Cs137. No other isotopes because of some errors with other substances than those three during the last weeks.

 

[biggerten]

With respect to this the information contained in this report.

"



When I worked on the construction of Pilgrim 1 in 1970 the diesel generators were radiator cooled, each had six starters, each starter had its own energy source and on site was a minimum of six months of fuel. In other words it was independently self sufficient, as an emergency system should be.

The system described in the publication above sounds like back up power for convenience. It was dependent upon, and assumed the the continued operation of, systems external to itself "sea water pumping and cooling system" for any operation.

I can understand a sea water-to-coolant heat exchanger in addition to a water-to-air heat exchanger, but not instead of it. I am,of course, assuming that the design purpose is the protection of human life.

I maintain commercial aircraft and I would not want to be responsible for maintaining anything designed by people who thought out the emergency(?) power system at Daiichi.

I wonder if we don't have translation issues here. The way I read that, it doesn't mean that cooling for the generators themselves was lost, but that the pumps that the diesels were to operate had nothing to pump. Perhaps the tsunami took out plumbing from the ocean or some heat exchange equipment. Diesels themselves require special coolant (SCA or OAT) to prevent internal damage (cavitation damage to cylinder sleeves, etc), sea water use would be extremely short term as a coolant in a diesel.

 

[AntonL]

I want to know where all the Strontium is.

Are TEPCO only testing for certain isotopes?

Tepco are testing but not releasing, in their own words

http://www.tepco.co.jp/en/press/corp-com/release/11041106-e.html]Regarding[/URL] the results on three nuclides (iodine 131, cesium 134,
cesium 137), we would like to assume those as definite result, however,
as for other nuclides, we will revaluate in accordance with the
preventive measures formulated after being given warning from Nuclear and
Industrial Safety Agency on April 1st.

and

http://www.tepco.co.jp/en/press/corp-com/release/11041106-e.html]Three[/URL] nuclides (Iodine-131, Cesium-134 and Cesium-137) are released as
fixed figures. Other nuclides figures are to be released as soon as
identified under instruction of NISA.

 

[gmax137]

... on site was a minimum of six months of fuel...

I think you're mis-remembering, or someone gave you bad info in 1970. Standard Tech Specs call for seven days diesel fuel onsite. There may be more fuel, but it wouldn't be in seismic storage tanks, and it wouldn't be available to the emergency diesels without manually opening cross ties and possibly using non-safety related transfer pumps. And I really doubt the six month figure. That would be over 3/4 million gallons per diesel generator (taking a swag at 200 gph). I've never seen diesel fuel tanks that size at a nuclear unit.

 

[tsutsuji]

Just watched TEPCO new drone video

Could you please post a link to that video ?

 

[artax]

some of it is here, not exactly close up is it!

http://www.youtube.com/watch?v=V0R7EoD752Q&feature=feedu

 

[Zoe Brain]

My knowledge of the radiation issue is almost zero, based on an NBCD warfare course I did 35 years ago.

I am however a safety-critical systems engineer, and am looking for lessons to be learned for hazard mitigation.

My initial thought is that another Tsunami from an aftershock at this point would ruin their whole day, and I don't like the way the seismic activity graph is trending. We should put mitigation strategies into effect for that *now*.

Long-term, for future designs - Assuming catastrophic loss of coolant/cooling ability, is there any way of designing a reactor to melt-safe? Split the pellet mounds into manageable masses when they're released from damaged rods via a ribbed inverted cone under the core, keep them well boronated, and divert via chutes into heatsink containers easy to enclose and remove for later action?

Right now, we're spreading really impossibly dangerous levels of contamination in the localised area, (and unacceptable levels of Cesium far and wide) just to stop a melthrough. Is it worth it? We have a number of reactprs not in cold shutdown, we're flushing water through them and transporting masses of volatiles out of containment and into the environment. The Iodine-131's dangerous in the short term, but Cesium-134 is the main worry for me. Half of that's still there in 30 years.

Storing spent fuel rods in situ now seems to be a really complicating factor when things go pear-shaped. Trouble is, I can't see a safer way of dealing with them, transporting them and their attendant coolant pool, even in small masses, to a remote site a few hundred metres away seems fraught with hazard. Maybe an automated shuttle tank, similar in concept to what they do with cooled-off rods, but far more dangerously hot.

 

[Borek]

Long-term, for future designs - Assuming catastrophic loss of coolant/cooling ability, is there any way of designing a reactor to melt-safe?

Yes. Astronuc will be able to give more details, but it is definitely possible and newer designs are already going in this direction. Check http://en.wikipedia.org/wiki/Passive_nuclear_safety

Right now, we're spreading really impossibly dangerous levels of contamination in the localised area, (and unacceptable levels of Cesium far and wide) just to stop a melthrough. Is it worth it? We have a number of reactprs not in cold shutdown, we're flushing water through them and transporting masses of volatiles out of containment and into the environment.

Alternative can be much worse. If temperatures go up we may have more explosions and much more contamination, thus stabilizing the reactors is probably the best thing that can be done at the moment.

 

[TCups]

There is a Russian rhyme that beginning chess players learn. Something is lost in translation, I am sure, but the gist of the verse is that a knight on the side of the board is a bad thing. This because its power is reduced to 4 the 8 potential squares it could attack.

For nuclear accidents, specifically the one in Japan, it appears to me that a "knight on the side of the chessboard" is a good thing with respect to population density and the long term results of radioactive contamination. Not that contamination of the ocean is good, but it will tend to dilute and everything that goes into the ocean will lessen long term exposure to the high density population of the people of Japan.

If I am following the thread correctly, one of the big questions, if not THE BIG QUESTION is how quickly the cores will cool to a "cold shutdown" temperature and therefor, hopefully eliminate the need to constantly pump water at the current rates required to cool the cores until they reach a "safe" temperature. That timeframe is uncertain because of some question of 1) the accuracy of the temperature measurements being in question, and 2) the potential of re-criticallity and re-heating of the core material delaying the cooling.

Is there any "reasonable" estimate as to when sufficient cooling of the core(s) might be expected to occur and thus eliminate the need for continued high volume water cooling and permit consideration of some type of permanent containment of the core material?

 

[tsutsuji]

Assuming catastrophic loss of coolant/cooling ability, is there any way of designing a reactor to melt-safe?

Lately, Areva has been insisting on the following :

For example, the EPR™ reactor is equipped with a corium drainage area that collects the substance if the reactor vessel is cracked.
Several design studies have helped optimize the EPR™ reactor’s recovery system, which is a large metal structure that ensures the passive, rapid cooling of corium from above, below and the sides.
This recovery system is located in a dedicated chamber within the reactor: the corium recovery chamber.

François Bouteille, Tuesday, April 05, 2011 3:02 PM http://www.areva.com/ajaxpub/dialog/DetailQuestion.aspx?idQuestion=668

 

[Krikkosnack]

Potential dispersion of the radioactive cloud after a nuclear accident in Fukushima

http://energheia.bambooz.info/index.php?option=com_content&view=article&id=163:potential-dispersion-of-the-radioactive-cloud-after-a-nuclear-accident-in-fukushima&catid=60:video&Itemid=85&lang=it

source http://www.eurad.uni-koeln.de/
http://www.eurad.uni-koeln.de/index_e.html

 

[Krikkosnack]

about alpha and beta particle detections... listen to the 4:18 - 4:30 intervall


What does he means?

 

[tsutsuji]

For nuclear accidents, specifically the one in Japan, it appears to me that a "knight on the side of the chessboard" is a good thing with respect to population density and the long term results of radioactive contamination. Not that contamination of the ocean is good, but it will tend to dilute and everything that goes into the ocean will lessen long term exposure to the high density population of the people of Japan.

Would not offshore be even better ? Kind of "knight outside of the chessboard", or "anchored nuclear submarine" then, although perhaps a little less crazy than the "sail the hull to a deep ocean trench and sink it" idea at http://www.guardian.co.uk/science/the-lay-scientist/2011/apr/06/1 (a lot of funny ideas there)

Reading the following :

An interesting article providing some details of the first two days of the accident:

http://www.yomiuri.co.jp/dy/national/T110411004567.htm"

Would it not be possible to have heavy lift helicopters and diesel generators ready in a number of airbases around the country, hoping that at least one of them will be far enough and safe from the earthquake, and able to take off and fly to the damaged plant as soon as the earthquake strikes ?

 

[Astronuc]

Astronuc,

Thank you so much for all the information you have supplied during this past month.

This forum has been invaluable as I struggle to understand what all the data, and corrected data, and crazy theories, mean to everyone living near the nuclear plants -- and the future of nuclear power.

Your insights are great. And now I must also thank you for saying when the data points are simply puzzling. Sometimes the explanation is not clear...hopefully we'll get more data soon that will help us understand the situation on the ground better.

-- JustGuessing

P.S. A month in, how do you think they are doing? What are you most concerned about? C an you start to image the cleanup?

Like a lot of others outside of the area, I'm wondering about what's really going on, and what the situation is with each reactor. It doesn't help to have conflicting or wrong information, such as some misreported isotopes.

As someone mentioned on the previous page (post #3507), I'm also wondering about the other nuclides, e.g., Sr-90. BTW - Cs-134 has half-life of 2.065 yrs and Cs has half-life of 30.1 years, so Cs-137 is the more persistent radionuclide.

Half-lives of the iodines are:

I-131, 8.0252 days
I-132, 2.295 hrs
I-133, 20.8 hrs
I-134, 52.5 min
I-135, 6.58 hrs

See attached figure.

I'm certainly concerned about the continuing release of radioactive materials from Units 1-4. TEPCO needs to stop the releaes ASAP, and figure out how to establish a closed cooling loop, and subsequently a treatment plan to decontaminate Units 1-4, and ultimately dismantle them - or possibly entomb them in such a way to preclude additional release of radioactive material.

As for the nuclear industry, there will be reassessments of current plants with respect to structural integrity in the event of a severe accident, as well as preparedness for several natural events and combinations thereof.

New plants are considered to be safer with better containment designs and more passive cooling designed into the plant. As far as I know, the newer plants have emergency backups in more protected locations. Siting of new power plants will receive more scrutiny.

 

[gmax137]

...
If I am following the thread correctly, one of the big questions, if not THE BIG QUESTION is how quickly the cores will cool to a "cold shutdown" temperature and therefor, hopefully eliminate the need to constantly pump water at the current rates required to cool the cores until they reach a "safe" temperature. That timeframe is uncertain because of some question of 1) the accuracy of the temperature measurements being in question, and 2) the potential of re-criticallity and re-heating of the core material delaying the cooling.

Is there any "reasonable" estimate as to when sufficient cooling of the core(s) might be expected to occur and thus eliminate the need for continued high volume water cooling and permit consideration of some type of permanent containment of the core material?

'Cold Shutdown' is made of two words: cold and shutdown

'Cold' implies both a closed loop cooling and temperatures below 212 F (100C) - the water circulated through the core becomes 'warm' (ie, not boiling) and it is cooled by a 'cool' source (ocean or river or cooling tower).

'Shutdown' means the reactivity is less than unity (typically less than 0.95) even at the cold temperature (the moderating capability of water increases as the temperature is lowered - so you need more boron or more control rod at lower temps).

 

[biggerten]

There is a Russian rhyme that beginning chess players learn. Something is lost in translation, I am sure, but the gist of the verse is that a knight on the side of the board is a bad thing. This because its power is reduced to 4 the 8 potential squares it could attack.

In English it's "Knight on the rim is dim".

 

[Krikkosnack]

http://www.asahi.com/english/TKY201104060126.html

When the Fukushima No. 1 plant was being built, Japan was importing technology from the United States and learning from a more advanced nuclear power nation. The No. 1 plant was considered a "learning experience." A former TEPCO executive said, "The Fukushima No. 1 plant was a practice course for Toshiba and Hitachi Ltd. to learn about GE's design on a trial-and-error basis." With the exception of the No. 6 reactor, the other five reactors at the Fukushima No. 1 plant are Mark I boiling-water reactors developed by GE.

http://www.europe1.fr/International/Des-traces-de-strontium-autour-de-Fukushima-496411/
Des traces de strontium, un élément radioactif produit par la fission nucléaire, ont été trouvées dans les sols et dans des plantes près de la centrale atomique de Fukushima-Daiichi,

http://www.lefigaro.fr/actualite-fr...pour-l-arret-de-la-centrale-de-fessenheim.php
La catastrophe nucléaire de Fukushima pourrait faire une victime collatérale en Alsace: Fessenheim. La centrale la plus vieille de France, mise en service en 1977, suscite en effet de nombreuses inquiétudes.

http://japan.failedrobot.com/
This map visualises crowd-sourced radiation geiger counter readings from across Japan. Click on the circles to get more information on the source of each reading.

 

[AtomicWombat]

You are a new poster here and i understand you haven't gone over the thousands of posts. All the things you mention were discussed here a while ago and debunked basically.
Reactor 3: The big blast is not directly related to the destruction of the top parts of the reactor, there were images posted here that show it's still there, with a crane collapsed over it, and steam escaping from the connection chute between that and the SFP. Also notice that the truss structure over the containment is intact unlike over the SFP. The thermal imagery, somehow surprisingly paints a rather rosy picture, with nothing substantially warm. A lot of seemingly hot spots arise from changes in the range of the IR measurements, with debris lying around at essentially ambient temperature. There are hot spots (70degC) over the SFP and the leaking parts from the PCV but that's about it, the rest are more or less cooler than a human being (less than 36degC), if a person was there it would be glowing red.

I've been with this discussion pretty much since the start and the possibility of the No.3 explosion originating in the primary containment and blowing off the containment plug has NOT been debunked; it has been debated with no clear consensus so far.

I don't believe this occurred. At the time of the explosion TEPCO was pumping in water using a fire engine. You don't overpressure a massive pressure vessel and not have a nylon fire hose still attached to the feed line not burst. If the RPV over-pressurized then every pipe, fitting, connection to the reactor with a lower pressure rating would have gone first, followed by the RPV assuming it didn't depressurize fast enough.

The RPV is approximately 6 inches thick. The pressures required to yield a 6 inch thick piece of steel even at elevated temperatures is huge. I understand the reactor has an operating pressure, but the failure pressure is much higher.

The failure mode of an over pressurized reactor with a corium slag at the bottom would be to fail the bottom of the RPV. This is the same failure mode you see when a water heater fails. It looks like this..



If that occurred with the reactor we'd be looking at the reactor vessel sitting somewhere outside of the building.

This is why you design the system to fail anywhere but the RPV.

I'm not going to dig up the maths again but under reasonable assumptions the explosion that destroyed building 3 had enough overpressure to exceed the RPV operating prerssure by 2-3 times.

Corium melt dropping into the drywell is NOT the same failure mode as a water heater. The steam and Zr-H2o explosion would cause a pressure rise outside the RPV and the explosion could bypass the RPV, which does not fully occlude the primary containment.

The mechanism of the building 3 explosion remains open, but any explanation MUST explain why it is clearly different from the explosion in builkding 1.