Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Astronuc]

Precipitating event:

http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/
Magnitude 9.0 (upgraded from 8.9)
Date-Time:
Friday, March 11, 2011 at 05:46:23 UTC
Friday, March 11, 2011 at 02:46:23 PM at epicenter

Location: 38.322°N, 142.369°E
Depth: 32 km (19.9 miles) set by location program

Distances:
129 km (80 miles) E of Sendai, Honshu, Japan
177 km (109 miles) E of Yamagata, Honshu, Japan
177 km (109 miles) ENE of Fukushima, Honshu, Japan
373 km (231 miles) NE of TOKYO, Japan

Tsunami information -
http://iisee.kenken.go.jp/staff/fujii/OffTohokuPacific2011/tsunami_prop.html


Summary of Fukushima Daiichi I, Units 1-4.
Ref: http://www.tepco.co.jp/en/press/corp-com/release/11032810-e.html

Unit 1(Shut down)
-Explosive sound and white smoke were confirmed after the big quake occurred at 3:36 pm Mar 12th. It was assumed to be hydrogen explosion.
-At approximately 2:30 am on March 23rd, seawater injection to the nuclear reactor through the feed water system was initiated.
-At approximately 10:50 am on March 24th, white fog-like steam arising from the roof part of the reactor building was observed.
-At approximately 11:30 am on March 24th, lights in the main control room was restored.
-We had been injecting seawater into the reactor, but from 3:37 pm on March 25th, we started injecting freshwater.

Unit 2(Shut down)
-At approximately 6:00 am on March 15th, an abnormal noise began emanating from nearby Pressure Suppression Chamber and the pressure within the chamber decreased.
-At 6:20 pm on March 21st, white smoke was confirmed arising from the top of the reactor building. As of 7:11 am on March 22nd, smoke decreased to the level to nearly non-existent.
-We have been injecting seawater into the reactor, but from 10:10 am on March 26th, we started injecting fresh water (with boric acid).
-At approximately 4:46 pm on March 26th, the light in the main control room was restored.
-We had been injecting fresh water into the reactor utilizing fire pump, however, we switched over to utilizing temporary electrical pump from
6:31 pm on March 27th.

Unit 3(Shut down)
-Explosive sound and white smoke were confirmed at 11:01am March 4th. It was assumed to be hydrogen explosion.
-At 8:30am on March 16th, fog like steam was confirmed arising from the reactor building.
-At approximately 6:15 am on March 17th the pressure of the Suppression Chamber has temporarily increased. We were preparing to implement measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive material to outside) in order to fully secure safety. However, at present, it is not a situation to immediately implement measures and discharge air containing radioactive material to outside. We will continue to monitor the status of the pressure of the reactor containment vessel.
-At approximately 4:00 pm, March 21st, light gray smoke was confirmed arising from the floor roof of the Unit 3 building. On March 22nd, the color of smoke changed to somewhat white and it is slowly dissipating.
-At approximately 10:45 pm on March 22nd, the light in the main control room was turned on.
-At around 4:20 pm on March 23rd, our staff confirmed light black smoke belching from the Unit 3 building. At approximately 11:30 pm on March 23rd and 4:50 am on March 24th, our employee found no signs of smoke.
-We had been injecting sea water into the reactor pressure vessel, but from 6:02 pm on March 25th, we started injecting freshwater.
-We had been injecting fresh water into the reactor utilizing fire pump, however, we switched over to utilizing temporary electrical pump from 8:30 pm on March 28th.

Unit 4 (outage due to regular inspection)
-At approximately 6 am on March 15th, we confirmed the explosive sound and the sustained damage around the 5th floor rooftop area of the Nuclear Reactor Building.
-On March 15th and 16th, we respectively confirmed the outbreak of fire at the 4th floor of the northwestern part of the Nuclear Reactor Building. We immediately reported this matter to the fire department and the related authorities. TEPCO employees confirmed that each fire had already died down by itself.
-At this moment, we do not consider any reactor coolant leakage inside the reactor happened.


I assume and expect that fresh water is borated in order to prevent to ensure the cores and SFPs remain subcritical.

First I want to thank the many contributors to this forum especially the moderators/mentors. I have read it all from the beginning and understood more than I would have thought. Thanks for the clear and concise explanations. Keeping up with it has been a bit like chasing the pot of gold at the end of the rainbow though.

Thanks for that, Liam. Good stuff!

 

[AntonL]

Silence from the IAEA for 30 hours. Unusual, as they have updated several times a day most days.

So much happened in the last 24 hours - I think they are pressing for real explanations
the IAEA cannot afford to put wrong information out - just my opinion.

 

[|Fred]

By the looks (and by experiece of photographing documents) they seem to be photographed documents and I suspect leaked. Please note the Pu sampling report id from the 22nd today is the 28th and Tepco only made official statement on 28th - why not on 22 or 23rd

Yes those sample were taken on the 22 and the 23 only released today (2 hours ago)and journalist were pissed.. same for the trench with water they were tested yesterday and they only released info today..

Again as explained if you watch those Press Conference on the right inside you have a social chat and the journalist upload the document as soon as they are handled... its media 2.0 if you like.

 

[ivars]

http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&p=31435#p31435"

 

[georgiworld]

Yes those sample were taken on the 22 and the 23 only released today (2 hours ago)and journalist were pissed.. same for the trench with water they were tested yesterday and they only released info today..

Again as explained if you watch those Press Conference on the right inside you have a social chat and the journalist upload the document as soon as they are handled... its media 2.0 if you like.

I would like to know if Tepco released the PU results only after learning that it had been leaked. The timing seems too coincidental.

I would also like to know if there is any other way PU could get into the soil if fission is not ongoing.

 

[AntonL]

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301313213P.pdf

Dr. Sekimura of Tokyo university pointed out the possibility of damage to
the fuel in the spent fuel pool of unit-3 since it would appear that the heavy
crane have dropped into the fuel pool in this movie. (05:40, March 28)

 

[razzz]

http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&p=31435#p31435"

I think the 'I'm a Little Teapot' song is more appropriate than 'Sixteen Tons' hopefully the teapot(s) don't boil dry.

I'm a special teapot,
Yes, it's true,
Here's an example of what I can do,
I can turn my handle into a spout,
Tip me over and pour me out!,

 

[TCups]

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301313213P.pdf

In part, from above reference:

"Dr. Sekimura of Tokyo university pointed out the possibility of damage to the fuel in the spent fuel pool of unit-3 since it would appear that the heavy crane have dropped into the fuel pool in this movie. (05:40, March 28)"

[STRIKE]I wonder if this makes sense:

1) vertical shaft
2) SFP3
3) Fuel rod handling equipment in SFP3
4) Region of the transfer chute and gate[/STRIKE]

CORRECTION:

The photo originally annotated is a photo detailing the north end of the top floor of building 3. The pool pictured, therefore, has to be the equipment pool, not the spent fuel pool of unit 3. I have deleted it to avoid any confusion.

 

[|Fred]

I would like to know if Tepco released the PU results only after learning that it had been leaked. The timing seems too coincidental.

once again and for the last time those are not leaked doc.
Tepco do Press Point every day several time a day. During those P.P they hand out Xerox to the press. Some of the Press upload an tweet those document as they get them.. Just watch the web stream..

@Reno Deano
Yes well one could expect that AIEA has a crisis head quarter with people watching 247 despite the 7-8 hour difference and updating everything in real time .
But as I picture it , there might be some lag: people watching and getting report from tepco in real time, getting those report to the annalists knowledge to understand and study them the next morning, and will eventually ask some confirmation of follow up to tepco, before they post anything.. etc etc

 

[AntonL]

We discussed a view days back about international teams working hard to help solve this problem.

Only today it is confirmed that Tepco is seeking actively help, a bit late it seems

TEPCO seeks French help to resolve nuclear plant crisis
PARIS, March 28, Kyodo

Embattled Tokyo Electric Power Co. has asked nuclear power-related concerns in France for support in resolving the crisis at its crippled Fukushima Daiichi nuclear power plant, the French industry and energy minister said Monday.

TEPCO sought support from such concerns as Electricite de France SA, Areva SA and the Nuclear Energy Agency, Eric Besson said during a radio program. The country's public radio said the details of the Japanese utility's calls remain unknown.

EDF announced a set of relief measures March 18, including the dispatch of experts and robots to the Fukushima plant in the wake of radiation leaks following a magnitude-9.0 earthquake and tsunami. But a media officer for Besson said the package is separate from TEPCO's request for support.

==Kyodo

 

[PietKuip]

in this document (http://www.nisa.meti.go.jp/english/files/en20110327-1-5.pdf ) i understand there has been mistakes about I-134 and possibly other elements. But even without these I-134 and Co-56 numbers, something troubles me.

As i understand, they can only measure up to 1 sieverts with current equipment there (press reports worldwide are 1 sieverts per hour but original documents show MORE than 1 sievert per hour without more details. In this pdf, measurements inside Unit 3 are at 750 msv/h).

Knowing that for example :
I-131 - Unit 2 : 1.3×10E7 vs Unit 3 : 3.2×10E5
Cs-137 - Unit 2 : 2.3×10E6 vs Unit 3 : 5.6×10E4
the list goes on, but from what i see most elements are about 50 times higher in Unit 2 compared to Unit 3.

My question is : is there a way to calculate (approximately) the real number of Sv/h in Unit 2 (and outside Unit 2 probably now...), as we know Unit 3 water surface is at 750 msv/h ?

When the activity of the water is 50 times higher, the dose rate above the water is also 50 times higher, because it is the same brew of isotopes. Edit: assuming equal depth.

So yes, the dose rate in the turbine hall of unit 2 is about 30 sievert per hour.

Which makes it impossible to do work there.

 

[TCups]

When the activity of the water is 50 times higher, the dose rate above the water is also 50 times higher, because it is the same brew of isotopes.

So yes, the dose rate in the turbine hall of unit 2 is about 30 sievert per hour.

Which makes it impossible to do work there.

Activity in the contaminated water has been specified as sieverts per hour AT THE SURFACE. Would the absorbed dose be greater under the surface, as with a worker standing in the contaminated water?

 

[AntonL]

When the activity of the water is 50 times higher, the dose rate above the water is also 50 times higher, because it is the same brew of isotopes.

So yes, the dose rate in the turbine hall of unit 2 is about 30 sievert per hour.

Which makes it impossible to do work there.

Clever move to report >1000mSv , with 30Sv confirmed the exodus starts

Now considering the large area, what would the the radiation be say on the floor above?
or is 30cm to 40cm of concrete floor slab be sufficient shield?

 

[jlduh]

EDF announced a set of relief measures March 18, including the dispatch of experts and robots to the Fukushima plant in the wake of radiation leaks following a magnitude-9.0 earthquake and tsunami. But a media officer for Besson said the package is separate from TEPCO's request for support.

I want to mention that since the very beginning, TEPCO as refused any help from american experts, then refused the proposal of AREVA/EDF to send robots from France, and also refused help from IAEA (IAEA receives report from NISA which gets information from TEPCO as TEPCO is THE only source of information for what happens in the plant). Now it is confirmed that TEPCO is asking help from France.

These are facts. But they may lead to political conclusions... which i won't draw!

Pietkuip, you said:

When the activity of the water is 50 times higher, the dose rate above the water is also 50 times higher, because it is the same brew of isotopes.

So yes, the dose rate in the turbine hall of unit 2 is about 30 sievert per hour.

Ouchhhhhh...

thanks for the clarification!

But I see in many articles written that the radiation is 1 Sievert/h in turbine building 2, which i interpret then as a mistake from a misleading info if I understand well: is it that difficult to have instruments measuring more than 1 sievert/h? Again that's unbelievable so see how information is biased because of inaccuracies and again misleading infos from TEPCO... Saying it's "more than 1 Sievert/h" when it's probably 30 Sievert/h is a misleading way (as a minimum!) of saying things, don't you think?

 

[|Fred]

France, offered a week ago a few robots design to operate when men could not, Tepco or Japan , politely declined judging they were not necessary at the time. They likely reconsidered
(As far as we know Tepco did not refuse the 100t of boric acid, 3000 mask , 10 000 radiation suit, 20 000 Glove sent by Areva / EDF on the 17/18th)

 

[Astronuc]

That seems to be correct, steam coming from the transfer chute area, what are the implication for the containment - TCups that drawing of yours with orange flame marks seems very plausible.

As for the condition of the fuel in SFP with heavy stuff dropping in we can only speculate, An explosive shockwave followed by a crane falling into the pool, could that have "Tsunamied" a bundle of fuel rods out of the pool, that we speculated to have observed in other photos?


Below image of crane in block 4 for comparison, seems to gone missing in block 3
and for block 1 we can see in the video the roof wrapped around the crane

I believe the image is from - http://www.youtube.com/modchannel/?gl=JP&hl=ja
11-03-27 (March 27, 2011) 10:11:06 (video 2:32 / 4:21)

It seems similar to the screen shot I took.

I expect that the refueling or fuel handling machine is parked over or at the end of the spent fuel pool.

There is another shot of a yellow cap, which is probably the drywell head/cap of unit 4.

I would expect that the dry well cap is on the opposite end of the building from the spent fuel pool.

 

[TCups]

I believe the image is from - http://www.youtube.com/modchannel/?gl=JP&hl=ja
11-03-27 (March 27, 2011) 10:11:06 (video 2:32 / 4:21)

It seems similar to the screen shot I took.

I expect that the refueling or fuel handling machine is parked over or at the end of the spent fuel pool.

There is another shot of a yellow cap, which is probably the drywell head/cap of unit 4.

@Astronuc -
Yes. Just so we are on the same page --
The drywell cap and fuel handling machine in the screen shots you referenced are from unit 4, where,
1) the explosion appeared less intense than in unit 3, and
2) the fuel rods had been taken out of the reactor core 4 and put in the SFP 4
3) the fuel handling machine from unit 4 has been visible on all previous videos, I believe.

The annotated photo with the proposed location of the fuel handling machine actually in the SFP is from unit 3. The suggestion that the fuel handling machine is actually in the pool came from the reference in the initial post #1760
https://www.physicsforums.com/showpost.php?p=3215310&postcount=1760

To Recap
The venting steam is coming (or initially came) from unit 3, in an area where I suggest there may have been damage to the chute and gate forming part of the primary containment for RV3. I postulate that had the water level in SFP 3 been low, then there would have been no water behind the gate and that the loss of hydrostatic pressure behind the gate, plus possible compromise of the pneumatic seals of the gate, plus one hell of an explosion, may have damaged the primary containment at the location of the gate, whether the hydrogen explosion originated from within the drywall containment or from the top floor of the building.

The reinforced concrete weight bearing columns, east and west, coupled to the large rails for the overhead crane tended to hold the sidewalls together, such that the main force of the explosion (actually in both units 3 and 4) seem to have blown out the north-south walls and the roof.

In unit 3, the north wall weight bearing columns actually collapsed and the overhead crane ended up atop an adjacent building below on the north side of bldg 3.

 

[ivars]

http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&p=31438#p31438"

 

[Borek]

We discussed a view days back about international teams working hard to help solve this problem.

Only today it is confirmed that Tepco is seeking actively help, a bit late it seems

It doesn't state when they asked for help.

 

[|Fred]

about Japan Earthquake: nuclear plants , Meti just reported today http://www.meti.go.jp/press/20110328007/20110328007.pdf
level 0 INES event at the Toukai power plant, The concentration of radioactive materials released was less than 1 in 4,000 of legal threshold

 

[M. Bachmeier]

France, offered a week ago a few robots design to operate when men could not, Tepco or Japan , politely declined judging they were not necessary at the time. They likely reconsidered
(As far as we know Tepco did not refuse the 100t of boric acid, 3000 mask , 10 000 radiation suit, 20 000 Glove sent by Areva / EDF on the 17/18th)

Ah What, 3000 mask, 10 000 radiation suite etc...

That's anticipation or (pre)-planning for a really bad event...

I'm feeling more than just a little political at the moment...

 

[Lefteris]

It seems that plutonium was detected at the soil near the plant
http://english.kyodonews.jp/news/2011/03/81609.html

Why is it mentioned as separate news? What is the significance of it?

 

[jensjakob]

When the activity of the water is 50 times higher, the dose rate above the water is also 50 times higher, because it is the same brew of isotopes.

So yes, the dose rate in the turbine hall of unit 2 is about 30 sievert per hour.

Which makes it impossible to do work there.

Who can confirm or dismiss this calculation?

It is a serious turning point we're looking at - and it will be very interesting to get a second opinion,

 

[Reno Deano]

Yes those sample were taken on the 22 and the 23 only released today (2 hours ago)and journalist were pissed.. same for the trench with water they were tested yesterday and they only released info today..

Again as explained if you watch those Press Conference on the right inside you have a social chat and the journalist upload the document as soon as they are handled... its media 2.0 if you like.

The samples (pressurized and non-pressurized) need to be prepped to allow counting (reduce volume on high activity samples), counted several times, along with decay of high activity short lived radionuclides so the spectrum is cleaned up. Detectors can only absorb so much radiation, so samples need to be diluted or counted from a distance.

I still want to know if the upgrades to the post accident reactor coolant sampling system, performed as designed (NRC NUREG - 0737, Post TMI Action Item II.B.3). Some plants spent hundreds of thousands (some cases over a million) of dollars on these systems. I, as many, considered that the complexity of the systems would only allow it to be use once (even at that) and then buried under a pile of lead. All systems required an in-line filter (within the reactor compartment) to screen out large particles/chunks so the system's small diameter piping and pipetting apparatus would not clog up.

 

[Reno Deano]

France, offered a week ago a few robots design to operate when men could not, Tepco or Japan , politely declined judging they were not necessary at the time. They likely reconsidered
(As far as we know Tepco did not refuse the 100t of boric acid, 3000 mask , 10 000 radiation suit, 20 000 Glove sent by Areva / EDF on the 17/18th)

It is a good chance that most of the protective clothing France' sent will not properly fit the Japanese person.

 

[jensjakob]

Fukushima trenches news coverage:


High level radiation now in trenches outside Tubine building.

 

[Reno Deano]

NEI: UPDATE AS OF 1:30 P.M. EDT, MONDAY, MARCH 28:
Tokyo Electric Power Co. has detected isolated, low concentrations of plutonium in the soil at the Fukushima Daiichi nuclear power station. The density of plutonium is equivalent to the fallout that reached Japan from nuclear weapons testing during the Cold War, the company said.

TEPCO conducted analysis of plutonium contained in the soil collected on March 21 and 22 at five locations at the Fukushima Daiichi plant. Plutonium 238, 239 and 240 were detected, however just two of the samples may be the direct result of the recent incident, considering the ratio of the plutonium isotopes.

"The density detected in the plutonium is equivalent to the density in the soil under normal environmental conditions and therefore poses no major impact on human health," TEPCO said. The company said it plans to strengthen environmental monitoring inside the station and surrounding areas.

 

[Bob S]

...But I see in many articles written that the radiation is 1 Sievert/h in turbine building 2, which i interpret then as a mistake from a misleading info if I understand well: is it that difficult to have instruments measuring more than 1 sievert/h?

A properly designed radiation measuring instrument can easily measure 30 Sieverts per hour with little saturation or nonlinearity.

1 Sievert = 1 joule (of energy deposition) per Kg = 0.001 joules per gram

1 Sv/hr = 280 x 10^-9 joules per gram-sec

Because it takes about 35 eV to create an electron-ion pair in nitrogen (for example), the current in an ionization chamber would be about

1 Sv/hr = 7.9 nanoamps per gram of nitrogen gas (or air). 1 liter of air at STP is about 1.29 grams.

So 30 Sv/hr = 310 nanoamps per liter of gas in the ionization chamber.

For high dose rates, the ion chamber must be properly designed to minimize the effects of space charge (in the gas) on the electric fields in the chamber, which can affect the charge collection efficiency.

Radiation levels of this order are often seen around particle accelerators. The radiation detectors are designed to measure over 1 Sv/second. See

http://ab-div-bdi-bl-blm.web.cern.c...ectors/Literature/schaefer_biw02_tutorial.pdf

Bob S

 

[Paul F.]

New poster here.. I've been following this thread since last saturday with great interest (and varying levels of understanding).

I have a couple questions (hopefully reasonably intelligent ones).

Regarding the contaminated water in the containment basement(s);
I'm not fully understanding the nature of the radioactive contamination; is it radioactive isotopes dissolved in the water, or is it more likely particulates in suspension?
I've been wondering if some of the sea water filtration type equipment that desalinates sea water might be an effective "trap" to help decontaminate some of the water that's accumulating, or if filtration would be ineffective on dissolved elements?

Second;
Regarding the "long term" containment at the Fukushima site, after the more critical short-term stabilization and clean up occurs...
I know there's a lot we DON'T know yet, that we'll need to know more about before a "long term" plan can be developed, but in broad terms; How will the site most likely be managed in the 5 to 50 years in the future time frame?
Is it likely that Units 1, 2, and 3 will be walled up in an enormous sarcophagus building, to be dissassembled over the next 40 years?

Or (again, pending more information coming out about the states of the RPV and Containment), is it likely that substantial clean-up and removal of spent fuel in the SFP's will likely be able to happen without a giant tomb being built?


Thanks to everyone again for an outstanding, calm, rational discussion without the hype and hyperbole that the "news" talking heads have been giving.


Paul F.

 

[Demidrol]

NEI: UPDATE AS OF 1:30 P.M. EDT, MONDAY, MARCH 28:
Tokyo Electric Power Co. has detected isolated, low concentrations of plutonium in the soil at the Fukushima Daiichi nuclear power station. The density of plutonium is equivalent to the fallout that reached Japan from nuclear weapons testing during the Cold War, the company said.

Good evening!
Plutonium appears after an explosion on 3 reactor scattered?