Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Rive]

The wall of the PCV is thick enough to be a shield against a reactor on full steam (what means the whole inventory AND the working reactor together). For now, there is only the inventory.
So my bet is on the contaminated building.

 

[zapperzero]

I skimmed all 4 of the videos. I see girders and corroded piping, the lining of the PCV (lots of that), I see some kind of grille or walkway, I see what looks like garden hoses but should be hydraulics conduits for the control rod drives.

I do NOT see streams of water (the "rain" notwithstanding), nor do I see standing water anywhere in the videos.

All in all, it looks as if aside from the downpour, nothing is amiss. Very odd.

In other news, it's amateur hour all over again at TEPCO... The camera was stuck on the business end of the scope, knowing full well that it's going into a high radiation field...

 

[tsutsuji]

http://mainichi.jp/select/jiken/news/20120120ddm001040022000c.html The endoscope investigation was done by 34 Tepco employees who worked from the inside of a shielded cabin [see diagram]. The maximum exposure was 3.7 mSv (less than the planned exposure of 5 mSv). The peeling off of the painting of the PCV wall reveals that it was exposed to high temperature and high humidity for a long time.

http://www.shimbun.denki.or.jp/news/main/20120120_04.html The endoscope was able to look down to the grating (PCV first floor) at OP 9.5 metre, so that the water level must be lower than this. As part of severe accident countermeasures, a water level gauge is installed at OP 8.3 m, which switches on when submerged, and this switched on signal is being received. For this reason, it is possible to estimate that the water level is between OP 8.3 and OP 9.5 m, but Tepco said : "the integrity of the water level gauge is unclear, so it is necessary to carefully evaluate that matter". Pictures are extremely unclear because of the radiation noise and of the water drops dripping on the camera. Tecpo said "as the water drops will be reduced as the reactor is further cooled, our main problem is the radiations". Unit 2 was chosen because a penetration was available and with consideration for working safety. At unit 3 a penetration is available, but the radiations in the reactor building are high, and working conditions are difficult. Concerning unit 1, whether a suitable penetration is available or not is being investigated. At present there is no plan to perform endoscope investigation in those two units, as the priority is to analyse the results of unit 2's endoscope investigation in detail.

http://www.tepco.co.jp/en/news/110311/index-e.html unit 2 endoscope videos are available

 

[Yamanote]

Well, so no special news from the endoscope investigations, except the water level thing.

I find it somehow interesting to see the current status of the cleanup work at Fukuichi:
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120120_02-e.pdf

What do you think, good progress, bad progress? Everything possible is done? Or much more could/should be done?
I would really appreciate to read your opinion.

 

[Rive]

Some pictures after cleanup attached, some others - maybe: a mosaic - is in progress... Does somebody recognizes anything?

Ps.: there is too much 'rain' inside... IMO it's not the condensed water but the cooling water.

 

[Joffan]

I didn't find the radiation noise a real problem in viewing those videos. You pretty quickly cancel it out. The "rain" was occasionally a problem but at least it gave a sense of where "up" and "down" are.

Nice picture clean-up Rive, I look forward to more!

 

[duccio]

In the second picture of Rive's, it seems that the C shaped bar has melted or anyway has deformed. Anybody with an opinion on that?

 

[dezzert]

Recent news about emergency power for sensors being disconnected in November 2010:

Does anyone have a clue what exactly this ERSS is monitoring? Reactor data (pressure, temperatures) for example?

The Emergency Response Support System (ERSS) is not what failed at the plant. It was the media converter, a device which relays real time temp and radiation readings from the reactors to both the ERSS and SPEEDI. The reason it wasn't functioning is because four months previous the line connecting it to a power source was cut and Tepco couldn't find a cable long enough at the time to reconnect, so they left it as it was, as they didn't consider it an "urgent task".

http://mdn.mainichi.jp/mdnnews/national/news/20120120p2a00m0na008000c.html

There are conflicting media reports concerning this data feed. Depending on which article or report you read it was operational at some point in time on the 12th, 13th or not at all. Ill research more

 

[NUCENG]

Some pictures after cleanup attached, some others - maybe: a mosaic - is in progress... Does somebody recognizes anything?

Ps.: there is too much 'rain' inside... IMO it's not the condensed water but the cooling water.

Without some sense of scale I can't be sure but the first picture shows a 90 degree elbow with threaded fittings. That may be a cooling water line to the drywell coolers. The second picture has dense packed metal tubes within some curved supports. I don't think they are CRD guide tubes because that would be inside the shield wall. They could be CRD hydraulic lines outside the shield wall. No guarantees. I'll wait for the mosaic.

 

[Rive]

I'll wait for the mosaic.

Sorry, I can't do it as it seems :-( The trick requires plenty (hundreds) of frames about the same view, and - due the spherical distortion of the cam - from the same position. There isn't enough of this kind of frame series in the released videos. Even small movements are problematic, because the noise prevents any automated alignment algorithm to be effective.

There will be only a dozen 'enhanced' picture soon, but most of them from different viewpoints. They will not fit for a mosaic.

About the scale: what's illuminated there is close to the cam. This can give a hint. I think the yellowish tubes are ~ 1 inch, the brown packed ones maybe 2 inch in diameter.

 

[SteveElbows]

In the second picture of Rive's, it seems that the C shaped bar has melted or anyway has deformed. Anybody with an opinion on that?

If you are referring to its slightly curved appearance in that image, I think we'd need to take into strong account the possibility of slight image deformation caused but the lens setup of the endoscope.

 

[clancy688]

And what is with unit 2 temperature: http://www.tepco.co.jp/nu/fukushima-np/f1/images/12011612_temp_data_2u-j.pdf ?

Just FYI, the sensor's gone by now.

http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/12012212_temp_data_2u-e.pdf

So first it measures rising temperatures at the CRD. And then suddenly it's giving us readings from Pluto. Or some other planets where it's as cold as -200°C.


I guess there are two likely answers for such a behaviour:

1) Something heats up the sensor until it fails
2) The sensor was broken all along

So what are the implications of the first case? Corium flowing out of the RPV, first heating the sensor up and then killing it? But why ten months after the shutdown?

 

[jim hardy]

sounds like wet extension wires to me.

thermocouple effect, dissimilar metals in contact with each other, gives you tens of MICRO-volts per degree.

battery effect, dissimilar metals in contact with electrolyte, gives tens or hundreds of MILLI-volts, usually overwhelming the theromcouple.

negative temperature is pretty good clue.

have they changed water injection recently?

 

[Rive]

Some more pictures.

Ps.: don't ask about the orientation...

 

[zapperzero]

don't ask about the orientation...

well, the grid thing is a walkway below the penetration level, so that's "down"

 

[jim hardy]

been seawater in there?

 

[zapperzero]

been seawater in there?

Monday, March 14 2011 seawater injection was first attempted at reactor 2 (containment breach occurred the next day).

As water flowing from the reactor building basement to the turbine building basement was found later to be contaminated heavily, we can assume that there is a direct path for water to flow through the RPV and then the PCV/torus walls.

 

[jim hardy]

there was talk at one time of flooding the containment
which cools the vessel directly from its outside
and is a suggested mitigation action in that (now famous) ORNL report.

but i don't remember hearing whether they actually did it.

 

[Rive]

It was for the first month, as I recall, and they had given up with it when they noticed that the water actually pumped in had to be enough to fill the containment several times.

 

[NUCENG]

If you are referring to its slightly curved appearance in that image, I think we'd need to take into strong account the possibility of slight image deformation caused but the lens setup of the endoscope.

No argument from me. Your interpretation is just as likely as mine. But it looks curved to me.

 

[NUCENG]

Sorry, I can't do it as it seems :-( The trick requires plenty (hundreds) of frames about the same view, and - due the spherical distortion of the cam - from the same position. There isn't enough of this kind of frame series in the released videos. Even small movements are problematic, because the noise prevents any automated alignment algorithm to be effective.

There will be only a dozen 'enhanced' picture soon, but most of them from different viewpoints. They will not fit for a mosaic.

About the scale: what's illuminated there is close to the cam. This can give a hint. I think the yellowish tubes are ~ 1 inch, the brown packed ones maybe 2 inch in diameter.

You may be right. I'm not trying to be argumentative, but how do you make those estimates? What do you know anout the focal length and distance from the lens?

 

[duccio]

If you are referring to its slightly curved appearance in that image, I think we'd need to take into strong account the possibility of slight image deformation caused but the lens setup of the endoscope.

If you take a ruler, the other support structure or pipe, more dark, is curved as well, but in the opposite direction, so either it's the lens as you said, or we are watching the side of the RPV and so it is really curved (I'm no expert to say that), or (but I believe less) they deformed.

However, what drew my attention was the brownish spot. From the shadow it looks as if the side of the support is broken, either rusted (but isn't it too brilliant for being rust?) or melted

 

[Rive]

You may be right. I'm not trying to be argumentative, but how do you make those estimates? What do you know anout the focal length and distance from the lens?

I don't know anything about the cam itself. But there are plenty of hints on the pictures:
- as the camera light illuminates the various objects, depending on the distance
- the water drops and flows on the objects (for example on the picture about the packed brown pipes you can see some drops hanging on that belt-like object, and if you check the videos, you can see some water flows on the yellowish tubes too)
- rust spots
- the deposite on the containment wall (what also calibrates the strength of the light)

It was not really an estimate based on science.

If you are referring to its slightly curved appearance in that image, I think we'd need to take into strong account the possibility of slight image deformation caused but the lens setup of the endoscope.

Those lens has some brutal spherical distortion. If you check those tubes as the cam moves, they bend differently on every frame. That's why I couldn't easily stack together enough frames to average out the noise.

However, what drew my attention was the brownish spot. From the shadow it looks as if the side of the support is broken, either rusted (but isn't it too brilliant for being rust?) or melted

Wet rust is brilliant, that's OK. But melted... I don't think. There is a concrete wall between the cam and the bottom of the RPV, so I don't expect to find any melted object.

About the rust: here is a photo about a drywell of Browns Ferry NPP:
http://umners.files.wordpress.com/2011/03/a.jpg

Some (less critical) items there are clearly not built with the best material available, so rust attack seems possible (especially at high temperatures and with seawater).
Also there are some stacked brown pipes at the right side.

 

[elektrownik]

http://enenews.com/just-in-after-m5-1-quake-radiation-dose-spikes-to-highest-level-since-april-at-detector-northeast-of-tokyo-double-average-chart
http://enenews.com/tepco-admits-radiation-levels-fukushima-increasing-releasing-70000000-bqhr-reactor-3-leaking

 

[rowmag]

http://enenews.com/just-in-after-m5-1-quake-radiation-dose-spikes-to-highest-level-since-april-at-detector-northeast-of-tokyo-double-average-chart

I checked the weather for then, and the radiation spiked occurred during a time when it was snowing in Tsukuba, AND the wind was blowing straight from Fukushima Daiichi. (By the way, the radiation started to rise before the earthquake, so that is probably not the cause. And the radiation stopped when the snow stopped.) Similar to previous spikes associated with precipitation and wind coming from F1.

Someone in Tokyo also apparently saw a rise there (further downwind from Tsukuba), did an isotope analysis, and found it was Lead-214 and Bismuth-214 -- radon daughter products. Obviously they weren't kicked up out of the ground (it was snow this time, not rain), but apparently swept out of the air.

Seems nothing to worry about, but kind of curious -- is it possible that the big pile(s) of scrap uranium at Fukushima Daiichi is serving as a giant radon source? Just from decay of the exposed uranium.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120125/index.html On 25 January, the 9-member government's investigation committee held its first (non public) meeting since the release of the interim report. At the end of February they will hold a meeting with foreign specialists, hearing their opinions, which could result in adding new investigation topics. The final report is expected for the end of July.

 

[Joffan]

Someone in Tokyo also apparently saw a rise there (further downwind from Tsukuba), did an isotope analysis, and found it was Lead-214 and Bismuth-214 -- radon daughter products. Obviously they weren't kicked up out of the ground (it was snow this time, not rain), but apparently swept out of the air.

Seems nothing to worry about, but kind of curious -- is it possible that the big pile(s) of scrap uranium at Fukushima Daiichi is serving as a giant radon source? Just from decay of the exposed uranium.

Interesting analysis. I suppose it's possible that the melted fuel is liberating radon into the water which is being carried out of containment and being released into the air, but I would also wonder if the same effect is visible with snowfalls with the wind in other directions. Maybe this is just within the bounds of a normal precipitation effect.

 

[Yamanote]

http://enenews.com/just-in-after-m5-1-quake-radiation-dose-spikes-to-highest-level-since-april-at-detector-northeast-of-tokyo-double-average-chart
http://enenews.com/tepco-admits-radiation-levels-fukushima-increasing-releasing-70000000-bqhr-reactor-3-leaking

I am not sure what this means and where it comes from. Unfortunately there are a lot of stupid statements around on the Enenews page, so it is neither a reliable source of information nor a big help to me...

One can also clearly see this radiation spike in the Tokyo graph, but the level is back to normal now:

http://monitoring.tokyo-eiken.go.jp/monitoring/graph.html

 

[Yamanote]

By the way, there is nothing special to see at the Fukuichi on-site radiation monitoring, (except that snow makes a good shielding):

http://www.tepco.co.jp/en/nu/fukushima-np/f1/index-e.html

Actually, this part of the discussion should be in the contamination thread...

 

[rowmag]

Interesting analysis. I suppose it's possible that the melted fuel is liberating radon into the water which is being carried out of containment and being released into the air,

The radon could escape directly to the atmosphere from the holes in containment (the ones from which the steam was coming last year), couldn't it?

but I would also wonder if the same effect is visible with snowfalls with the wind in other directions. Maybe this is just within the bounds of a normal precipitation effect.

Could be, though there have been plenty of rain events in the past year without any associated spike in radiation. The spikes only seem to be associated with being downwind of F1, at least the ones that I have checked in the past.

As for moving this to the contamination and consequences thread, I'm not sure I would classify a whiff of short-lived radon daughter products as contamination, and it does not appear very consequential. I consider this more in the realm of "remote sensing" of what may be going on at the plant -- if it can be determined to be from the plant.

The other possibility that occurs to me is that there is also an old uranium mine (from the war) in Fukushima near the airport, and there is also a radon onsen near there, so maybe it is possible the wind blew some radon from there instead. Not as directly upstream of Tsukuba as F1 was at the time of the spike, but not completely out of the stream either. I'll post some wind maps later to show what I mean.

In any case it would be good to have an explanation of what is going on, so people don't need to freak out next time this happens. (In that sense, perhaps it does belong in the contamination and consequences thread.) It is also just interesting.