Japan Earthquake

Japan Earthquake | Page 2194

Just found something. Drywell rad sensors part of this system: , "Primary Containment Isolation Valves (PCIVs),
by lillymunster 8/20/2011 7:31:50 PM

Says the radiation sensors will shut down certain valves when a preset high reading level is achieved.
by lillymunster 8/20/2011 7:32:20 PM

Found the information on Drywell Radiation Sensors but it doesn't say much about physical location :
2.c. Drywell Radiation - High
High drywell radiation indicates possible gross failure of the fuel cladding.
Therefore, when Drywell Radiation - High is detected, an isolation is
initiated to limit the release of fission products. However, this Function is
not assumed in any accident or transient analysis in the FSAR because
other leakage paths (e.g., MSIVs) are more limiting.
The drywell radiation signals are initiated from radiation detectors that are
located in the drywell. Two channels of Drywell Radiation - High Function
are available and are required to be OPERABLE to ensure that no single
instrument failure can preclude the isolation function.
The Allowable Value is low enough to promptly detect gross failures in
the fuel cladding.
This Function isolates the containment vent and purge valves.
by lillymunster 8/20/2011 7:39:19 PM

@lillymunster the two channels may be A and B.
by Edano 8/20/2011 7:44:42 PM

we have Drwell A & B and Torus A & B sensors in all 3 reactors.
by Edano 8/20/2011 7:46:17 PM

www3.nhk.or.jp

New system improves Fukushima decontamination

Tokyo Electric Power Company says it has succeeded in increasing the capacity of a water decontamination system at the Fukushima Daiichi nuclear power plant by 1.5 times.

The utility began to use a Japanese-made system on Thursday along with a French-made system to remove radioactive substances from water. The water is then being injected back into the reactors to cool them.

TEPCO decided to introduce the new system as the existing decontamination system was plagued with problems, and the foreign-made components repeatedly clogged up.

The firm tested the performance of the new equipment for 2 days by running the contaminated water through it after the water had gone through the existing device.

Full-fledged operation of the new system alone began on Friday night.

TEPCO says the decontamination level using both systems has been increased by 1.5 times to 70 tons per hour from the original 45 tons.

The system's operating rate has been only 69 percent of full capacity, far below the initial target of 90 percent.

The firm hopes the new addition will boost the capacity and help achieve stable circulatory cooling of the reactors.

Sunday, August 21, 2011 01:59 +0900 (JST)
www3.nhk.or.jp
by Edano via Www3.nhk.or.jp 8/20/2011 7:55:05 PM

@Edano yes I think so from what I read. I found a NRC document talking about the Watts Bar NPP and their rad reading sensors in high temp conditions such as LOCA. I think this is where TEPCO got the idea to label those as defective automatically. But if you read the NRC doc it explains what is considered enough to call the gauges correct. I think the gauges are correct based on the NRC finding but I think the tech folks had already determined that here. pbadupws.nrc.gov
by lillymunster 8/20/2011 7:56:30 PM

Instrument channel numbers for the high rad containment sensors (drywell sensors) at Browns Ferry. If we can find a detailed schematic of one of these old reactors we could likely isolate the location of the sensors High Range Primary Containment
Radiation Monitors and Recorders
(RR-90-272, RR-90-273, RM-90-272C,
and RM-90-273C)
by lillymunster 8/20/2011 7:59:17 PM

back.. how's the search lilly
by dean 8/20/2011 8:00:16 PM

@lillymunster Drywell A in #1 might be in fact defect because it constantly shows "0", and zero is impossible.
by Edano 8/20/2011 8:01:11 PM

@dean tidbits but no jackpot yet.
by lillymunster 8/20/2011 8:10:14 PM

I will continue to search for that and the corium.. be back in a bit
by dean 8/20/2011 8:10:47 PM

@ariadne I've always found the comments to the articles on HuffPo go on for weeks after the much sparser stories themselves, and usually have great links (including to our stuff). In that comment section, for instance, this just came up: online.itp.ucsb.edu
It's the slides from a public lecture by UCSB's Ben Monreal, delivered March 16th. There are some errors in it that we know now only in retrospect (it was about the time Jo and Edano and dean and everyone on Reuters were looking at the JAIF numbers and trying to figure out how the numbers didn't say "containment breach" or "meltdown"), but he illustrated it all and delivered it to the public the 16th. Big props for that.
by RadioGuy 8/20/2011 8:11:00 PM

@Edano the mention of Watts Bar talked about the coaxial cable vulnerable to heat and that both cables run down by the lower portion of containment where they could be exposed to too much heat. So #1 could have been too hot at some point and ruined the coax?
by lillymunster 8/20/2011 8:11:20 PM

I did find some other terminology that may help find data on these drywell rad sensors. One referred to it as "CHARM" though a brief search didn't result in much. If you see this acronym that is what it means. Also, references to "Primary Containment" rather than drywell or secondary containment refer back to the drywell sensors. Another term used containment high range radiation monitors
by lillymunster 8/20/2011 8:13:58 PM

@lillymunster well, i guess 3000° is hot enough to melt cables down ....
by Edano 8/20/2011 8:32:33 PM

New office to address radioactive contamination

Japan's minister in charge of nuclear crisis has said that the government will establish a task force next week to address radioactive contamination in areas around the Fukushima Daiichi nuclear power plant.

Goshi Hosono made the comment at a meeting with Fukushima Governor Yuhei Sato on Saturday.

Hosono added that the central government will set up a team in Fukushima to facilitate radioactive decontamination work.

Hosono said the government will allocate budgets to deal with the ongoing nuclear disaster as it bears heavy responsibility for the accident at the Fukushima plant.

Hosono said removal of radioactive substances is becoming the most important issue.

Saturday, August 20, 2011 14:46 +0900 (JST)
www3.nhk.or.jp
by Edano 8/20/2011 8:35:02 PM

I found this but I am not sure if the sensors mark the rad sensors. It is a schematic for primary containment ventilation for BWRs. Since the drywell rad sensors shut the vent system it could be in here. www.nucleartourist.com
by lillymunster via Nucleartourist 8/20/2011 8:38:58 PM

If I am reading this right the penetrations and systems on the right side would be the air removal system that would be shut off by a high rad reading from a sensor. Does not specifically locate and label the sensor.
by lillymunster 8/20/2011 8:41:10 PM

Standby Gas treatment systems www.nucleartourist.com
by lillymunster via Nucleartourist 8/20/2011 8:42:18 PM

Jake Adelstein just tweeted to somebody that he can point to Japanese books by plant designers do you think there would be diagrams? you could ask him?
by elainekirk 8/20/2011 8:52:59 PM

Goodness you can see the steam at the front of #1 now that dark frame is there
by elainekirk 8/20/2011 8:55:01 PM

@elainekirk not sure. There seems to be a really tight hand on schematics and blueprints in Japan. I am at a loss to find a descriptive of the sensor location short of a wiring schematic.
by lillymunster 8/20/2011 8:55:36 PM

www.flukebiomedical.com
This is an example of a High-Range Containment Monitor, designed to mount to the containment wall: www.flukebiomedical.com

Operations Manual [pdf] is here: assets.fluke.com
by es via Flukebiomedical 8/20/2011 8:58:49 PM

@es cool
by Edano 8/20/2011 9:02:42 PM

@elainekirk What do you suppose all those cranes are doing over by the common sfp? Or is it the waste treatment plant? There seems to be a lot of low-lying steam drifting to the right of it, though it's right at the resolution limit so it mostly looks like jpeg aliasing.
by RadioGuy 8/20/2011 9:09:12 PM

@Edano Doesn't really help us much with the specific positioning of the Dai-ichi monitors, unfortunately :(
by es 8/20/2011 9:09:39 PM

@es they seem to be very robust, no electronic inside.
by Edano 8/20/2011 9:11:16 PM

When the wind dies for a minute, it rises in a medium-gray cloud.
by RadioGuy 8/20/2011 9:13:41 PM

@RadioGuy I dont know I never seen to gett tbs on a clear day either
by elainekirk 8/20/2011 9:14:01 PM

@RadioGuy wow it is putting on a show for you now I wonder if that fracture in the ground next to unit 4 actually went as far as the common?
So many unanswered questions ie why are they forever emptying unit 6 turbine rm
by elainekirk 8/20/2011 9:14:34 PM

That time it looked like it was drifting from R3... it blocked the bottoms of all the cranes for a minute.
by RadioGuy 8/20/2011 9:16:00 PM

That's a fair amount of steam given the amount of wind trying to blow it away.
by RadioGuy 8/20/2011 9:16:56 PM

There is some consistent steam that isn't pixel jumping by the crane and 3-4 vent tower
by lillymunster 8/20/2011 9:19:36 PM

@Edano Yes, the specs are interesting in that respect - it's designed to withstand the high radiation, pressure and moisture of a LOCA event, as well as seismic activity.
by es 8/20/2011 9:19:48 PM

yes, and even some of the picel jumping spreads to 4 or 5 pixels, to it's aliased, but there's something there to alias
by RadioGuy 8/20/2011 9:20:26 PM

What does not make sense about the common pool steaming is it has electricity, thus cooling. It holds old fuel. So why would it be losing water or becoming hot now.?
by lillymunster 8/20/2011 9:20:44 PM

4 as far as we know has no basement level heat source. #3 is about the only steam generation source in that area right now. So either a pool is cooking, but all the SFP and common pool now have cooling systems. Or 3 is pushing out steam from various spots?
by lillymunster 8/20/2011 9:22:18 PM

I don't know if it relates to the cranes or not, so it may have nothing to do with the common pool.... my first question was about the cranes before the wind died down enough to see the steam. That last blast of steam made it look like it's blowing from R3, maybe 4
by RadioGuy 8/20/2011 9:22:44 PM

as a non techi could I ask if lumps of molten dripping through into ground water would cause the steam bursts
by elainekirk 8/20/2011 9:26:29 PM

Where are they staging the practice session putting the shower curtain together? Could that be what all those cranes are doing. It looks like 5 or 6 cranes.
by RadioGuy 8/20/2011 9:26:49 PM

@RadioGuy possibly. They talked of a preassembly process to lower time of people near unit 1.

Elaine, possibly. When we were getting the massive steam shows that was one concern was bits of melted fuel dropping into a body of water.
by lillymunster 8/20/2011 9:33:58 PM

@elainekirk There was also speculation that corium cracking would expose the molten center to contact with more cooling water, hence the post-quake steam shows. If the corium cracked at the bottom and broke its seal enough to squeeze loose a blob, that would seem to do it too. It would all be lots easier if they would just scan for the corium. It's so hot, both heat and radioactivity, it's weird that we've read nothing of them trying to locate it.
by RadioGuy 8/20/2011 9:34:11 PM

@lillymunster I guess the positive side of that, other than the radiation released, is that it would be pinching off bits to cool, rather than the whole mass going at once.
by RadioGuy 8/20/2011 9:36:19 PM