Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[MadderDoc]

In Dec 13., it was stated that 189 610 tons would have been treated (http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f12np-gaiyou_e_2.pdf , page 12). Assuming a constant rate of 500 tons per day since then, the current amount would be around 280 000 t.

If the average Cs-137 concentration would have been around 1e5 Bq/cm3, the filters would now contain some 140 PBq of Cs-137, i.e. about 15 - 25 % of the entire initial inventory of cores 1-3.

Interesting to see from your spreadsheet that a large proportion of it seems to have been taken out of circulation within just the first couple of months.

I dug around and found the latest report to NISA on the accumulated water:
http://www.tepco.co.jp/en/press/corp-com/release/betu12_e/images/120530e0201.pdf
It says that by the end of May 2012, a cumulative total of 340 000 tons has been treated.

 

[MadderDoc]

There are stains on the 2011 photo:
https://www.physicsforums.com/attachment.php?attachmentid=48104&stc=1&d=1339053367

Yes, but I'd say, they are not as pronounced and in as many paths. This may have been a progressively developing thing.

I think it's not salt. As I know the top level of U4 were not 'sprayed': even the first attempts to fill the pool were more or less accurate (with the concrete pump).

I also lean to later events or processes. While I can't exclude that there has been some spraying, I don't think it has caused these stains, they look too much to me as stains produced by water -- the way they channel around obstrúctions on the wall. Generally I think there is much greyness and deposits from concrete dust in the building. Rainwater is perfectly capable of dissolving substances from fresh concrete dust and reprecipitate a whitish deposit in runners down a wall. Alternatively, there might be a superficial yellowish discoloration of the wall produced by the heat of the explosion, which water can wash away.

<..>
Top of the equipment racks on the right:
http://cryptome.org/2012-info/daiichi-12-0526/pict8.jpg

There are some distinct splotches of white on some of the equipment in this photo which was clearly not there earlier, and which may well be from spraying. However generally the greyness seen I'd assign to a combination photo artefact and concrete dust.

 

[MadderDoc]

Unit2 2nd floor

Spawned by a question on another forum I realize this image is the only published one I know of, showing anything from the 2nd floor of Unit 2 (It is from the landing on the 2nd floor of the north east stairwell)

There would have been made video recordings of at least two Quince tours taking it across the north end of the second floor, however no part of those recordings appear to have been published.

http://gyldengrisgaard.eu/fuku_docs/Dose-of-atmosphere-temperature-measurements-by-robot1_Unit2_2ndfloor.png

 

[SteveElbows]

They spraying I sometimes mention was of anti-scatter/dust suppressant material. I can't find proof right now that they did this for reactor 4, but there are TEPCO videos which show this activity being carried out at other buildings using the cream rather than green substance. It was done late May/early June 2011, here for example is the webcam video of them doing it to reactor 1, the action starts after about 3 minutes of the video. http://www.youtube.com/watch?v=ntjOm7x-KaY&lr=1

Other possibilities seem equally plausible, or some combination, e.g. the anti-scatter agent is eventually partially washed away by rain, or by occasions where they may have overfilled the pool (seem to remember an issue with this happening at some point after they switched to a better way to cool the pool, but could be a false memory).

 

[MadderDoc]

They spraying I sometimes mention was of anti-scatter/dust suppressant material. I can't find proof right now that they did this for reactor 4, but there are TEPCO videos which show this activity being carried out at other buildings using the cream rather than green substance. It was done late May/early June 2011<..>

Probably it would have been some time between June 6th:
http://photo.tepco.co.jp/en/date/2011/201106-e/110611-03e.html
and June 30th:
http://photo.tepco.co.jp/en/date/2011/201106-e/110630-04e.html

The spraying may have been repeated later. I see strong indication of recent spraying with dust inhibitor somewhere near the valve area shown in the photo from July, at http://photo.tepco.co.jp/en/date/2011/201107-e/110706-02e.html.

 

[MadderDoc]

Looking at this Quince capture, I get the impression that a sudden event must have caused quite some flood of very rusty water to pass by here. Alternative explanations I've sought, like leaks, or corrosion in a damp environment does not seem to me to be any good in explaining the pattern and location of the rusty discolouration.

 

[nikkkom]

Looking at this Quince capture, I get the impression that a sudden event must have caused quite some flood of very rusty water to pass by here. Alternative explanations I've sought, like leaks, or corrosion in a damp environment does not seem to me to be any good in explaining the pattern and location of the rusty discolouration.

Unit 2 was full of steam for weeks. Recall footage of its blowout panel steaming day and night.

It's quite possible that steam was condensing on locally colder surfaces and pooling on the nearby floor.

 

[MadderDoc]

Unit 2 was full of steam for weeks. Recall footage of its blowout panel steaming day and night.

It's quite possible that steam was condensing on locally colder surfaces and pooling on the nearby floor.

It is quite certain that steam was condensing inside the building, and that the water once it was condensed was generally transported downwards by gravity. We see the effects of this many places in the building.

However in this photo we see a uniform matte rusty deposition stretching from apparently a significant portion of the floor, and up a foot or so in a curved shape on the rightmost part of the vertical surface of the ventilation shaft. It is this pattern of rusty discolouration I think lacks an explanation. Certainly the rust didn't come there without presence of water, and it is very unlikely rust from local corrosion that we see. Rusty water has not come from above to this part, running down the ventilation shaft, and the discolouration also doesn't seem to fit the expected pattern of splashes from dripping rusty water from above to the nearby floor over a period of time.

 

[Rive]

It is this pattern of rusty discolouration I think lacks an explanation.

If it's a floor penetration (the same style what was found in first floor of U1 as I recall, as an intensive radiation source) then steam coming from the lower level can be an explanation.

 

[MadderDoc]

If it's a floor penetration (the same style what was found in first floor of U1 as I recall, as an intensive radiation source) then steam coming from the lower level can be an explanation.

I am not quite sure which mechanism it is you are proposing. Certainly the floor is penetrated there to make way for the metal duct (and of course to make way for the stairwell itself close by). The same video allows also a view to the metal duct seen from the stairwell landing directly below the landing on the 2nd floor.

Landing on 2nd floor with discoloured metal duct (picture right):

Looking up at same vertical duct from stairwell landing below (picture right):
http://gyldengrisgaard.eu/fuku_docs/Unit2_1-2nd_floor_NE.jpg

 

[etudiant]

Any more information on the water table contamination?
Nihonmatsu is uphill and well inland from the coast. We had been told earlier that TEPCO was keeping the water level in the plant low enough to generate ground water inflows, rather than outflows. Also, the consensus seemed to be that the ground water was flowing towards the ocean, rather than inland. So if your friends input is correct, it really undermines a lot of what we thought we knew about this site.

 

[MadderDoc]

Another Quince 2 survey of Unit 2 is planned for June 13th 2012. On the 2nd floor, the robot is scheduled to use a route from the NE to the NW stairwell as done during previous surveys. Hopefully this time there will be published imagery from along this route which might cast light on the discolouration we've been talking about. On 3rd floor, Quince 2 will meet again with Quince 1, which got stuck there close to the NW stairwell on October 20th 2011

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120612_01-e.pdf

 

[zapperzero]

Another Quince 2 survey of Unit 2 is planned for June 13th 2012. On the 2nd floor, the robot is scheduled to use a route from the NE to the NW stairwell as done during previous surveys.

Apparently the robot is going to be carried up the stairs by a human. Yay for automation!

 

[turi]

Apparently the robot is going to be carried up the stairs by a human. Yay for automation!

Yes, but only from the 1st to the 2nd floor. From the 2nd up to the 5th it seems to climb on its own (judging from the red and blue arrows in the pdf). Do they fear its umbilical could get entangled on the lower floors?

 

[rmattila]

Via ex-skf:


From Sankei Shinbun (6/13/2012):


２号機５階で毎時８８０ミリシーベルト　福島第１

Fukushima Daiichi (I) 880 Millisieverts/hour on 5th floor of Reactor 2

東京電力は１３日、福島第１原発２号機の原子炉建屋内部をロボットを使って調査し、５階の原子炉の真上にあたるコンクリート床付近で、毎時８８０ミリシーベルトの放射線量を計測したと発表した。作業員の５年間の被曝線量上限にあたる１００ミリシーベルトに約７分間で達する値で、東電は「５階に人が立ち入っての作業は困難」とみている。建屋内に目立った損傷はなかったという。

TEPCO announced on June 13 that it conducted the survey of the interior of the Reactor 2 building using a robot, which measured the 880 millisieverts/hour radiation near the concrete floor on the 5th floor right above the reactor. The 5-year cumulative maximum radiation exposure for nuclear workers (100 millisieverts) would be reached in about 7 minutes at that location. TEPCO thinks it will be difficult for [human] workers to enter the 5th floor. According to the company, there was no visible damage to the interior of the building.

国産の災害対策支援ロボット「クインス」の改良型が、５階まで自走して測定した。今回、最高値を計測した場所のコンクリート床の厚さは約２メートルで、格納容器の上端から約３．５メートル離れているという。

The improved version of "Quince", robot developed in Japan for disaster response support, went up to the 5th floor and measured the radiation. The concrete floor with the highest radiation level this time is about 2-meter thick, and about 3.5 meter away from the top of the Containment Vessel.

約４時間にわたる調査で、ロボットの被曝（ひばく）線量は５０５．６ミリシーベルトで、作業員９人の被曝線量は最大で３．９５ミリシーベルトだった。

The robot got 505.6 millisieverts of radiation exposure in the 4-hour survey, and the 9 [human] workers got the max 3.95 millisieverts.

 

[rmattila]

Presentation "Lessons of Fukushima-Daiichi NPP's Accidents to Contribute and to Ensure the NPPs Safety in the World" by Dr. Tadashi NARABAYASHI, Nuclear and Environmental Systems,
Hokkaido University:

http://mntk.rosenergoatom.ru/mediafiles/u/files/dok_en/Naraba.pdf

It appears some consideration is given to filtered venting systems that might in the future be back-fitted to old plants.

 

[SteveElbows]

Map of the reactor 2 robot survey results here:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120614_03-e.pdf

 

[rmattila]

Map of the reactor 2 robot survey results here:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120614_03-e.pdf

It seems the dose rates peak directly above the containment dome, and are at least roughly in line with the dose rates that could be expected to be caused either by a partially exposed core within the RPV, or by the nuclides deposited on the internal surfaces of the dome. I don't think much can be deduced concerning the possible amount of radioactivity that has leaked out from the containment.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120613/0500_suimen.html On 12 June Tepco tried to determine the water level inside unit 2's suppression chamber by measuring the temperature distribution with an infrared camera. The temperature is 38°C in the top part and decreases when you climb down, reaching about 35°C in the lower part. As they could not find an area with a large temperature difference indicating the boundary between the liquid phase and the gas phase, the position of the water surface remains unknown. In the future they will try to determine that water level using different methods.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120612_04-e.pdf Unit 2 S/C Water Level Measurement by an Infrared Camera

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120614_05-j.pdf This is about a new leak (0.5 to 1 cm above floor) in the Areva decontamination facility, which had been operated in closed loop since May 21.

http://www.tepco.co.jp/en/press/corp-com/release/2012/1205338_1870.html Some more unit 2 thermometers are getting worse (while not completely unusable, they are still available as "reference")

 

[zapperzero]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120613/0500_suimen.html On 12 June Tepco tried to determine the water level inside unit 2's suppression chamber by measuring the temperature distribution with an infrared camera. The temperature is 38°C in the top part and decreases when you climb down, reaching about 35°C in the lower part. As they could not find an area with a large temperature difference indicating the boundary between the liquid phase and the gas phase, the position of the water surface remains unknown. In the future they will try to determine that water level using different methods.

Eh. Maybe it's dry. Or maybe it's full.

 

[rmattila]

I don't think it would be possible for the water level inside the supression chamber to be below that in the torus room, as water is constantly being pumped inside the PCV and pumped out from the turbine buildings in order to keep the water level there about 1 meter below the ground water. I see no other mechanism than leaking to the torus room for the water in the PCV to get out, and this requires the water level in the PCV to be above that in the torus room.

EDIT: This was meant as a reply to a comment regarding the possibility of the water level in the PCV possibly being below that in the torus room. The comment was apparently removed while I was typing the reply, so this post is now quite irrelevant.

 

[tsutsuji]

Well, thanks for your reply anyway. Also the water level was measured with the endoscope as being a few centimeters above the drywell bottom. So it was quite stupid of me to imagine it could be much lower than this.

 

[Tepconium-311]

It is disconcerting to see in the latest helicopter footage that there has been so little apparent progress at the seaside of the plant. The building of the temporary tidal barrier seems to have come to a halt at Unit 4, and there is no indication of any progress of the steel pile barrier, the start of construction of which in the seafront of Unit 4 was announced many months ago. (If I understand the mid-term plan it is to not have a water tight barrier in place at the sea front before until some time in 2014, at the earliest).

There is groundwater inflow and outflow in basements.
Just helping disposal of radionuclides dissolved in basement water by slowly diluting them into ocean via groundwater.

Proceeding in such manner is helpful reducing storage tank hassles.
Good old Tepco already did some necessary preparations.
For example, covering seabeds around Fukushima-1 with concrete.
This delays and dilutes groundwater-supported disposal by spreading over larger area.

To be honest, wouldn't be installing a water tight barrier too early just be a big mistake?

 

[LabratSR]

Typhoon Guchol to hit Japan,

http://www.theweatherspace.com/news/TWS-61712-super-typhoon-guchol-japan.html

http://www.wunderground.com/tropical/tracking/wp201205.html

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120605/index.html The final version of Tepco's internal investigation report, which must be released this month, is nearly finished. [ The 2 December version was an "interim report"]. Against the cabinet investigation committee's accusation of mismanagement of the situation at units 1 and 3, it argues　in defence for example that "responding was actually difficult". However the report recognizes about unit 1, that there was not enough training to cope with blackouts. About unit 3, against the cabinet investigation committee report's claim that "the risk of running out of batteries had been minimized, which led to the water injection failure", Tepco's report says "as there was a worry that the water injection equipment was damaged, it was necessary to shut it down early".

http://www.tepco.co.jp/en/press/corp-com/release/2012/1205638_1870.html Release of the Fukushima Nuclear Accidents Investigation Report (Japanese only for now)

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120619_02-j.pdf at 12:19 on 19 March an employee found 8 wounds and heard noise coming from the wounds in a gas duct of the PCV gas extraction system at unit 3. At 14:40 it was confirmed that the gas was not released outside the duct as the negative pressure was maintained. PCV pressure, PCV hydrogen concentration, PCV gas extraction system flow rate remain unchanged. As an emergency measure, the duct was repaired with tape.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120619_02-e.pdf Unit 3 PCV Gas Control System Duct Damage

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120615_02-e.pdf The Protection Platform Installation on Unit 4 Spent Fuel Pool

( http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120608_03-e.pdf Purpose of protection platform on unit 4 spent fuel pool - 2012-06-08 )

http://genpatsu-watch.blogspot.com/2012/06/20126191800.html (from 19 June Tepco press conference) and http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120619_02-j.pdf 2/2 : A worker working to prepare the ground for the foundations of the unit 4 cover structure had his fingers (of both hands) pinched at 10:30 on 19 June when he was changing the "pit" (a part at the tip) of a boring machine. A supposedly attached casing fell down. He was sent to the unit 5/6 medical room, then to J-village and sent from J-village to a hospital in Iwaki at 12:51. It will take him 3 months to recover.

 

[tsutsuji]

http://www.tepco.co.jp/en/press/corp-com/release/2012/1205638_1870.html Release of the Fukushima Nuclear Accidents Investigation Report (Japanese only for now)

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120620/index.html Tepco released its final report. It generalises saying "As preparations against nuclear accident were complacent, pratical thinking was not sufficient". But many questions such as the cause of the large radioactive substance releases or the consequences of the earthquake remain unanswered more than one year after.

The report is based on hearing 600 people, on onsite surveys and data analysis.

There is no big difference with the interim report as regards the accident's causes, and it concludes: "It is impossible not to say that retrospectively there was complacency as regards tsunami estimates, and the insufficiency of preparations to resist tsunamis is the fundamental cause".

The response to the accident is evaluated as being basically appropriate as the people onsite responded desperately in a situation that exceeded assumptions. About the operation of emergency cooling equipments that the cabinet investigation committee had criticized as being inappropriate, while recognizing that there are points where preparedness was insufficient, it merely argues in defense that "response was in fact difficult".

Then it concludes, "As preparations against nuclear accident were complacent, during the response they were unable to imagine what was really happening onsite, and practical thinking was not sufficient".

Concerning the interference of the government, instructions quite out of touch of the real situation onsite were directly or indirectly given, "the plant manager was only torn between conflicting demands, and it was not a way to improve accident containing results".

The report also includes concrete proposals for the future: to study accident management under the assumption that nearly all equipment functions are lost, to complete meltdown preventing countermeasures, about the chain of command during an emergency, and the way to release information to the population.

Nuclear engineering specialist, Mr Miyano of Tokyo university says the report "is not sufficiently analysing the problems in past countermeasures and regulations". "It is questionable whether the true nature of the accident can be approached with this report only. 'concretely what should be regretted, what should be changed ?' it is necessary to extract the lessons, but it is difficult for this to be done by the accident's main protagonist Tokyo Electric alone. The conclusions must be drawn by analysing from the eyes of a third party."

 

[MadderDoc]

I think I've finally figured out what those dark structures at the seaside of unit 2 and Unit 1 turbine buildings really are. :-( Darned to have been so daft, thinking about it I had boxed myself in the vain hope that it might have been something to do with basic ground work to stopping contamination of the ocean, but alas, it is likely not.

In all simpleness, I believe those dark structures have been the construction sites for the sections to cover the lower east part of Unit 3, towards its turbine building. Here seen in an image from late May 2012:

http://gyldengrisgaard.eu/fuku_docs/daiichi-12-0528-01-hr_detail.jpg

And here below is a marked up view to the putative construction site for those cover sections, detail from original photo taken on February 28th 2012:

http://gyldengrisgaard.eu/fuku_docs/120313_01_detail.jpg

 

[MadderDoc]

There is groundwater inflow and outflow in basements.

Yes, since water treatment started about a year ago, the volume of water Tepco is handling has roughly doubled, corresponding to a net accumulation of about 400 m³/day, and it is too much to believe that this net inflow figure represents _only_ inflow.

Just helping disposal of radionuclides dissolved in basement water by slowly diluting them into ocean via groundwater.

Proceeding in such manner is helpful reducing storage tank hassles.
Good old Tepco already did some necessary preparations.
For example, covering seabeds around Fukushima-1 with concrete.
This delays and dilutes groundwater-supported disposal by spreading over larger area.

To be honest, wouldn't be installing a water tight barrier too early just be a big mistake?

Now groundwater-supported disposal proper is not something that happens fast, if it were only that I suppose doing something effective about the problem might wait until 2014. But I think the case is that the ground we are talking about is a landfill, now turned a radioactive dump, and under the surface it is criss-crossed with trenches, pipes and ducts -- that the area on the whole is as designed to facilitate fast liquid discharge to the ocean, and not at all a slow leaching bed. In that situation, to let on that it can wait years to put a stop to it is just disgraceful.

 

[SteveElbows]

Not much left of the upper parts of reactor 4 building now. I believe what we may be seeing in this video is dust caused by the cutting away of remaining parts of upper north-west wall.

 

[tsutsuji]

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120605_04-j.pdf At 20:03 on 4 June unit 4 SFP had an "airfin cooler panel alarm" ringing, and it was found that secondary circuit pump A had tripped with some traces of burning on the pump's terminal box. Pump B was started at 20:27. At 10:30 on 5 June, pump B was shut down in order to perform an inspection. As the pool temperature is expected to rise by 0.3 °C/hour, this is not considered as being a problem for pool temperature control.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120606/index.html Unit 4 SFP temperature reached 42°C at 5 PM on 6 June. As Tepco found a malfunction in the connecting part between motor and cable [that must be the terminal box] of the backup pump [that must be pump B] as well, they made repairs and restarted the pump after 6 PM, and the pool is being cooled again. Tepco explains: "as the pool is further cooled, the temperature might drop by 10°C in half or in one day".

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120608_02-e.pdf Pictures of the faulty pump cables.

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120614_05-j.pdf This is about a new leak (0.5 to 1 cm above floor) in the Areva decontamination facility, which had been operated in closed loop since May 21.

This leak has been investigated: a water level meter was wrong.

http://www.tepco.co.jp/en/press/corp-com/release/2012/1205585_1870.html "The leaked water is assumed to have come from the coagulation-sedimentation equipment of the decontamination apparatus. As a result of site investigation on June 15, it is assumed that the leaking part is the interspace of the piping penetration hole on the top side of waste liquid strage tank. And also it is assumed that the water of the tank flowed out, since the water did not flow downstream by shutting down the flow regulating valve of downstream pipes due to instantaneous descent of the level meter of the tank and inflow from upper stream was continued. The integrity verification was conducted on the same day, and the problem was confirmed. The level meter has been decided to be fixed".

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_03-e.pdf "Investigation Result of the Water Leak from the Decontamination Apparatus" with pictures and diagrams giving details about the failed tank.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120626/index.html Tepco made additional measurements of unit 4's reactor building walls' tilt. Last month a tilt thought to have been caused by the bulge created by the hydrogen expolsion was found at the western wall with a measurement of a 3.3 cm tilt for 13 m of height, which was about half the limit set by the Building Standards Act. Now they found 4.6 cm for 13 m of height on the third floor on the western side. All tilts are within the limits of the Building Standards Act. Tokyo Electric says the pool is supported by other pillars, etc. that are different from the outer walls where tilting was found, and that as a result of seismic analysis, there is no seismic safety problem.

http://photo.tepco.co.jp/date/2012/201206-j/120625_02j.html pictures of the unit 4 wall measurements (Japanese version)
http://www.tepco.co.jp/cc/press/2012/1205832_1834.html press release about the new unit 4 wall measurements (Japanese version)
http://www.tepco.co.jp/cc/press/betu12_j/images/120625j0201.pdf press release attachment (Japanese version) (with diagrams, etc...) "Report dealing on a study about seismic safety taking into consideration local outer wall bulging at Fukushima Daiichi unit 4 reactor building"

 

[zapperzero]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120626/index.html Tepco made additional measurements of unit 4's reactor building walls' tilt. Last month a tilt thought to have been caused by the bulge created by the hydrogen expolsion was found at the western wall with a measurement of a 3.3 cm tilt for 13 m of height, which was about half the limit set by the Building Standards Act. Now they found 4.6 cm for 13 m of height on the third floor on the western side. All tilts are within the limits of the Building Standards Act. Tokyo Electric says the pool is supported by other pillars, etc. that are different from the outer walls where tilting was found, and that as a result of seismic analysis, there is no seismic safety problem.

Any words on measuring error? Or was there actual change between one measurement and the next?

 

[zapperzero]

Not much left of the upper parts of reactor 4 building now. I believe what we may be seeing in this video is dust caused by the cutting away of remaining parts of upper north-west wall.

Quite so. I wonder if anything of that can be seen on the newly-shielded radiation counters at the site boundary.
EDIT: I stopped wondering and started looking
http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/2012monitoring/f1_lgraph-e.gif
lo and behold, there is a slight uptick starting on 6/23 or thereabouts.

 

[Joffan]

Quite so. I wonder if anything of that can be seen on the newly-shielded radiation counters at the site boundary.
EDIT: I stopped wondering and started looking
http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/2012monitoring/f1_lgraph-e.gif
lo and behold, there is a slight uptick starting on 6/23 or thereabouts.

I don't see the uptick, and I'm usually pretty good at spotting graphical subtleties. I wouldn't expect much because unit 4 wasn't very radioactive in the first place, and all (or almost all) the dust will be from concrete that hasn't seen the outside world since it was poured during construction.

 

[zapperzero]

I don't see the uptick.

Look again . The detector near the main building shows the most visible trend. You can also get the data in the tables (on the same page) and play with it. There might be another cause, of course, such as high winds.

 

[tsutsuji]

Any words on measuring error? Or was there actual change between one measurement and the next?

They are not measuring the same measurement points. The new measurement with the 46 mm horizontal difference is located on the 3rd floor, halfway between the rows R6 and R7, while the older measurement of "approx. 33 mm" for "West 2" in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120525_05-e.pdf 6/17, was located on the same floor but exactly on row R6.

There might be a small change of 1 mm between both measurements on west2/R6-3rd floor as the report now says 32 mm (instead of "approx. 33 mm").

I attach translations of the bottom of page 7/57 and of page 9/57 of http://www.tepco.co.jp/cc/press/betu12_j/images/120625j0201.pdf

page 7/57

page 9/57

 

[SteveElbows]

The camera zoomed in further when they did the next days cutting operation on east upper wall:



I'm more interested in how the painfully slow debris-removal is going at reactor 3, but cranes & stack tower tend to obscure the view of that, and we need a better resolution anyway.

 

[LabratSR]

Highest radiation found at Fukushima No.1 reactor

http://www3.nhk.or.jp/daily/english/20120628_01.html

 

[MadderDoc]

Highest radiation found at Fukushima No.1 reactor

http://www3.nhk.or.jp/daily/english/20120628_01.html

After all those months, with reams of stories told potentially elevating the information level of journalists and the lay public ...still to the NHK writer of http://www.gyldengrisgaard.eu/fuku_docs/nhk20120628_01.pdf -- inside or outside the reactor, a pressure vessel, a containment, or a suppression chamber -- are all just one porridge.

Even as regards the most interesting angle apparently to the writer -- the alleged record breaking radiation, there appears to be no memory of any previous potential record-holder (although in reporting of record breaking the dethroned party and the previous record traditionally get a mention). Has the measured >10,000 mSv/hr at the vent/SGTS pipe to the Unit1+2 exhaust stack last July been forgotten?

http://www.gyldengrisgaard.eu/fuku_docs/110805_1_detail.jpg​

 

[MadderDoc]

The camera zoomed in further when they did the next days cutting operation on east upper wall:



I'm more interested in how the painfully slow debris-removal is going at reactor 3, but cranes & stack tower tend to obscure the view of that, and we need a better resolution anyway.

Much of the unit3 debris removal has gone on at ground level, and around the building in a rather big radius -- the Unit 3 explosion was a very littering event indeed.

Comparing this June 18th 2012 photo, with this September 15th 2011 photo it can be seen that quite some progress has been made as regards getting close to the building proper as well as apparently establishing a foothold, a heavy duty elevated working platform at the east wall of the upper floors. I'd expect some of the equipment used currently at unit 4 will be relocated to unit 3 in time.

 

[Rive]

Highest radiation found at Fukushima No.1 reactor

http://www3.nhk.or.jp/daily/english/20120628_01.html

http://photo.tepco.co.jp/en/date/2012/201206-e/120627_01e.html
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120627_02-e.pdf

- Isn't that radiation a bit high compared to the water drawn from the T/B basement for decontamination?
- Why is the radiation decreases underwater?

 

[elektrownik]

- Why is the radiation decreases underwater?

The water blocks radiation so it is suggest that the radiation source is somewhere out of the water

 

[Rive]

The water blocks radiation so it is suggest that the radiation source is somewhere out of the water

As it was suggested elsewhere maybe it's the torus.

If the torus itself is watertight and the cooling water escapes where the torus connected to the DW then the water inside the torus might be there from the very first days -> much more heavily contaminated than the water drawn from the T/B basements.

 

[Tepconium-311]

The water blocks radiation so it is suggest that the radiation source is somewhere out of the water

Why then radiation increases strongly when approaching water?
Doesn't this indicate water surface emitting high radiation?

As it was suggested elsewhere maybe it's the torus.

If the torus itself is watertight and the cooling water escapes where the torus connected to the DW then the water inside the torus might be there from the very first days -> much more heavily contaminated than the water drawn from the T/B basements.

Sadly shielding obstacles like walking girders aren't shown in Tepco presentation chapter 3 to help explain radiation measurements. They are only indicated in chapter 2.
If torus is watertight, wouldn't radiation increase less sharply when approaching water surface?

Any expert ready to comment?

 

[NUCENG]

Why then radiation increases strongly when approaching water?
Doesn't this indicate water surface emitting high radiation?


Sadly shielding obstacles like walking girders aren't shown in Tepco presentation chapter 3 to help explain radiation measurements. They are only indicated in chapter 2.
If torus is watertight, wouldn't radiation increase less sharply when approaching water surface?

Any expert ready to comment?

Time, distance and shielding are the watchwords for assessing radiation doses.

Distance: If the water is contaminated, approaching it would result in increasing radiation. If the trus is the source and you are getting clo=ser to it as you approach the water, the same applies.

Shielding: As you get closer to the water you may be going into an area with less shielding. The torus itself is partly above the water level. Any contamination in the atmosphere of the torus or deposited on the structures inside the torus has only the thin shell of the torus as shielding. Core debris inside the containment may be creating radiation streams near the vents between the containment and torus.

Time: has any pumping operation been done which could have stirred up contamination? Does the radiation level change over time (other than decay) showing priods of increase and decrease?

If there is information on the makeup of the radiation (by isotope) or much more detailed geometry information you may start to chip away at this problem. Good luck.

 

[Tepconium-311]

Dear NUCENG, thank you for reply!

If I understand you correctly, published Tepco data only reveals high radioactivity in torus room, but not where it is from.
Your explanation sounds really convincing that there is something dangerous in torus, torus vents or nearby.

But, another thing I don't understand yet.
Somebody mentioned (iirc) that torus room of unit 1 is above groundwater level.
If this is correct, then this cannot be groundwater.

Can there be other paths for cooling water to reach basements than via leak in torus?
Because, if torus is watertight, how can there be so much radioactive water in reactor and turbine buildings' basements??

Sounds contradictory to me.
So, in other words, is there any real chance that torus is _not_ damaged?

 

[r-j]

What kind of radiation are they measuring?

 

[SteveElbows]

Regarding the reactor 1 torus room, is it fair to say that we should be considering some corium blowdown into the torus room as a possibility here? High radiation readings and TEPCOs typically understated comments about 'sediment' tempt me to wander in that direction, especially given the smaller physical size of reactor 1 containment and the length of time it went without water injection.

 

[SteveElbows]

Can there be other paths for cooling water to reach basements than via leak in torus?
Because, if torus is watertight, how can there be so much radioactive water in reactor and turbine buildings' basements??

Sounds contradictory to me.
So, in other words, is there any real chance that torus is _not_ damaged?

At least one study of mark 1 containment failure mentions the blowdown that I was just talking about. I wil try to find the study, but in a nutshell this process does not have to involve the torus itself being damaged. Rather core material that is splattered across the floor of containment eats away at the steel wall near to where it meets the steel floor, and gets into the space between the concrete and the large pipes (downcomers?) that connect containment to torus. This offers a pathways whereby core material can get into the torus room, without having to pass through the torus itself. This would also open up a pathway through which water injected into containment later on could get to the torus room.

There may be some technical inaccuracies in this description but its the best I can offer without having the report to hand.

Of course I do not mean to suggest that we now have anything like solid proof that this happened, just that we should consider it as a possibility given the survey.

 

[SteveElbows]

Having now watched the video and seen how much material they disturbed with the probes, I would like to retract by comment about the sediment.

 

[tsutsuji]

The 7th mid long term meeting was held on 25 June: http://www.meti.go.jp/earthquake/nuclear/20120625_02.html

The 6th meeting (25 May 2012) : https://www.physicsforums.com/showpost.php?p=3933442&postcount=13399

The 5th meeting (23 April 2012) : https://www.physicsforums.com/showpost.php?p=3881074&postcount=12979

The 4th meeting (28 March 2012) : https://www.physicsforums.com/showpost.php?p=3838108&postcount=12764

The 3rd meeting (27 February 2012) was translated into English on Tepco's website : http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/conference-e.html

25 June 2012 government-Tokyo Electric mid and long term response committee, steering committee (7th meeting)

http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02a.pdf Agenda
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02b.pdf Participants

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02c.pdf Abstract of the proceedings of 6th steering committee meeting

Document 2: Plant status
Document 2-1: Plant status
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02e.pdf Accumulated water storage status

Document 3 Study and execution of each special plan

3-1 Cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02f.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02g.pdf Unit 2 alternative thermometers installation progress status

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02h.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02j.pdf Status of multinuclide removal facility (ALPS) qualification test and installation works, and characteristics of waste objects
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf Subdrain purification test report
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02m.pdf Progress status of construction of underground water storage tanks
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02n.pdf Progress status of ground water bypass study

3-3 Countermeasures to reduce environmental radiations
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02p.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02q.pdf Management of debris, cut down trees, generated by the response to the accident
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02r.pdf Countermeasures against fire of cut down trees (branches, leaves and roots) during the summer season, and future plans.
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02s.pdf Suitability tests of decontamination techniques within plant premises
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02t.pdf Consequences on water quality of the covering of the sea floor in the harbour (as of June)
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02u.pdf Results of evaluation of additional releases from reactor building's primary containment vessels
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02v.pdf Results of yearly radiation exposure at the plant premises boundary (as of June)

3-4 Improvement of working conditions
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02w.pdf Schedule

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02x.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02y.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02z.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02aa.pdf Results of seismic safety study taking into consideration local outer wall bulging at Fukushima Daiichi unit 4 reactor building
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02bb.pdf Performance of preliminary underwater surveys (2nd and 3rd ones) in spent fuel pool for the purpose of removing debris at unit 3.
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02cc.pdf Performance of dry cask temporary storage facility construction work
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02dd.pdf Results of survey inside Fukushima Daiichi unit 2 reactor building (3rd ～ 5th floors)

3-6 Preparations for fuel debris removal
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02ee.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02ff.pdf Performance of survey into unit 1's torus room

3-7 treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02gg.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02hh.pdf Status of contaminated water analysis
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02jj.pdf Collection of samples to analyse debris and cut down trees

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02kk.pdf roadmap progress (abstract)

Document 5
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02mm.pdf Violations of safety regulations reflected in the first fiscal 2011 safety inspection at Fukushima Daiichi nuclear power plant (additional instructions)

25 June 2012 government-Tokyo Electric mid and long term response committee, technical development progress headquarters (7th meeting) (http://www.meti.go.jp/earthquake/nuclear/20120625_01.html )

http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_01a.pdf Agenda

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_01b.pdf Abstract of the proceedings of 6th meeting

Document 2
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_01c.pdf Decided projects for the global radiation reduction plan

Document 3
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_01d.pdf Securing education and human resources as seen from the mid and long term perspective

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_01e.pdf Organization of the "Fukushima Workshop" (provisional name) on development of machinery and equipments etc. toward the decommissioning of Tokyo Electric Power Company (K.K.) Fukushima Daiichi nuclear power plant