Japan Earthquake

Japan Earthquake | Page 2400

@dean need to add belching (or farting) sound effect to unit 3 explosion videos. :-)
by lillymunster 9/24/2011 1:26:11 PM

ha ha @ lilly :)
by dean 9/24/2011 1:29:19 PM

this is from a document on fuel melting------
The experiments are performed by producing a melt of un-irradiated uranium dioxide (extremely low levels of alpha radioactivity, easily avoided by the experimenters), zirconium alloy, and structural steel, in the proportions that would be present in a reactor core. This melt is sent through a nozzle used to simulate a pressure vessel lower head breach, and dropped onto concrete. Measurements are taken during the hours-long experiment using thermocouples and camera equipment, and the solidified material is examined after completion.

The experiments have shown that without water quenching, corium under conditions similar to those present at Fukushima Dai-ichi will ablate the meters-thick concrete pad at a rate of just millimeters per minute. Gases would build up within the containment at a rate which would require filtered ventilation of the containment in order to prevent rupture.

If, however, water is supplied to quench the corium as it spreads onto the reactor floor, the ablation occurs at 5-7% of the pre-quench rate, and production of gases is suppressed. The rate of ablation continues to undergo fits and starts, as the corium forms a solid crust, and then this crust is broken and re-formed.
by dean 9/24/2011 1:30:54 PM

by dean 9/24/2011 1:40:52 PM

Has anyone found any new news stories? Yesterday was absolutely dead.
by lillymunster 9/24/2011 1:46:09 PM

I haven't found much but I have been off on other searches to bolster up some of our findings @ lilly
by dean 9/24/2011 1:48:06 PM

@dean If those numbers were correct, the molten core at Fukushima Daiichi #1, #2 and #3 would have gone underground in a matter of days. That highly contradicts all the information we've had access to so far. How do you analyse this?
by Pedro Jesus 9/24/2011 1:48:40 PM

enenews.com hydrogen levels high... from ENE NEWS... 9-23
by dean 9/24/2011 1:51:15 PM

@ Pedro, it's hard to call, trying to translate tests done under controlled environments against real time in plant. With the uncertainty of where the corium is and if it's broken up or still somewhat of a mass, and with the absence of quenching water I would say we can't rule it out
by dean 9/24/2011 1:53:25 PM

Do we have postulated melt through days/times yet or just meltdown hours?
by lillymunster 9/24/2011 1:53:38 PM

@ lilly, I would think all of us could say that in worse case conditions the melts would occur quickly in terms of hours then the molten core-concrete interactions in terms of days
by dean 9/24/2011 1:58:46 PM

one point on the concrete flooring,, it is probably composed of around 35% rebar with different melt points that the breakup of concrete
by dean 9/24/2011 2:02:25 PM

@dean the rebar, the containment is heavily rebar laden. I know the video of fukushima construction shows it in detail. Also the lip of the steel liner where it meets the drywell floor is a melt point. It seems like it would then be a path for more corium to travel but the width is 2-3 inches between liner and air gap. Would that be enough for corium to spread down without cooling?
by lillymunster 9/24/2011 2:07:43 PM

@lillymunster But aren't those areas all covered with contaminated water that has been leaking?
by Pedro Jesus 9/24/2011 2:09:00 PM

I think we could build a timeline with what we know about watering, tepcos event actions, meltdown and melt through to get a good idea how things progressed and what the water did or didn't do.
by lillymunster 9/24/2011 2:09:27 PM

@Pedro Jesus the drywells?
by lillymunster 9/24/2011 2:09:45 PM

@lillymunster There's water everywhere inside those 3 units. That's why they've been installing filtering and decontaminating systems to be able to remove it before it starts leaking outside, possibly through the access doors. Or did I get it wrong?
by Pedro Jesus 9/24/2011 2:11:38 PM

what happened yesterday to cause the spikes www.tepco.co.jp
by elainekirk 9/24/2011 2:11:41 PM

c.r. hyman, "contain calculations of debris conditions adjacent to the bwr mark i drywell shell during the later phases of a severe accident,"@ LILLY.. this document may shed some lite on the timeline for BWR mark I
by dean 9/24/2011 2:14:10 PM

www.osti.gov
by dean 9/24/2011 2:18:39 PM

@ lilly this is the document for BWR MARK I
by dean 9/24/2011 2:18:56 PM

@Pedro Jesus it seems to be leaking out of the buildings everywhere below grade. If the torus is failed (or bottom of the drywell side) it is a straight water path out. We don't know for sure water level in containment if there is one. We have a water level for the building section below grade that houses the torus. That level is about 3/4 full of water, that would be below the drywell floor level
by lillymunster 9/24/2011 2:18:59 PM

@lillymunster Do you mean 3/4 of the lower section of the unit? According to the building designs I've seen that would cover the base mat under the RPV. That's not so far away from the unit's main access door, actually. The air tight door, I mean.
by Pedro Jesus 9/24/2011 2:27:53 PM

@Pedro Jesus outside of containment, the building basement. Let me grab a picture.
by lillymunster 9/24/2011 2:29:37 PM

water level maximum per TEPCO
by lillymunster 9/24/2011 2:30:18 PM

The water level if you go across the building would hit below the drywell floor. We know there is leakage out of containment, does it hold back any water inside or leak it all out?
by lillymunster 9/24/2011 2:31:16 PM

www.neimagazine.com HOT SALTY WATER CAUSES LEAK AT FUKU 4 SFP
by dean 9/24/2011 2:33:17 PM

@lillymunster That's what I mean. The base mat under the RPV is covered by water as shown in that diagram. The molten core will have deposited on the base mat so it would be under water.
by Pedro Jesus 9/24/2011 2:33:21 PM

I have found a video after the first few mins there are diagrams 2nd video commentary series "The situation in the reactor containment vessel instrumentation reactor pressure vessel" is published. www.tepco.co.jp
by elainekirk 9/24/2011 2:36:02 PM

@Pedro Jesus no the base mat isn't covered with water.
by lillymunster 9/24/2011 2:36:08 PM

@lillymunster Yes, it is, it shows on the diagram you've posted. The base mat is under the RPV. About your other question, according to TEPCO the RPVs are still holding some water inside. They adjust the water input to cover for the leakage and be able to maintain a certain level. The diagram you posted below only shows the water level outside the RPV, in the lower section of the unit. Check the latest update for more details. www.tepco.co.jp
by Pedro Jesus 9/24/2011 2:40:07 PM

one point... in the early stages of the accident where melt through is postulated and subsequent interaction with the pedistal area, there shouldn't have been water in those areas correct/
by dean 9/24/2011 2:42:44 PM

@Pedro Jesus give me a minute to do a better drawing. That one is a bit confusing
by lillymunster 9/24/2011 2:42:46 PM

@dean Correct.
by Pedro Jesus 9/24/2011 2:43:13 PM

Notice at sampling-point 3 net to the Unit-3 containment lid www.tepco.co.jp we see cesium-vapor-colored residue! See the prior cesium-color correlations I made here iangoddard.com to wit this new data fits such that where steam ejects we continually find cesium-vapor-colored residue. And in Tepco's new video, at sample point 3 we can see some steam even now. And it right there all this steam was billowing out back in March www.youtube.com
by Ian via Iangoddard 9/24/2011 2:43:20 PM

hello to all

TBS/JNN - live cam link has been changed again
determined: www.youtube.com
new link: www.youtube.com
by Vivre 9/24/2011 2:46:04 PM

ty Virve and hi
by dean 9/24/2011 2:46:25 PM

actual water leve/collection. Grey is solid concrete
by lillymunster 9/24/2011 2:48:13 PM

@Pedro Jesus we have RPV water levels, Building water levels. No containment water levels as far as I know.
by lillymunster 9/24/2011 2:49:24 PM

In my steam-explosion animation mapped onto Unit 3, notice houseoffoust.com that I have the ejection point at NW side of the well-cap rim lower than floor level. This was to account of the impression in the March footage (as well as from the slight steam seen there today) that the steam from the NW portion of the lid is emerging from some point below floor level. Additionally, the NW ejection point lines up with the lowest blown-out section of Unit 3, the NW corner that's blown out at the lower floor.
by Ian 9/24/2011 2:50:31 PM

@Ian do you think those were weak spots? Concrete plug really that heavy to prevent an upward blast? Something else?
by lillymunster 9/24/2011 2:54:29 PM

@lillymunster In this last diagram the concrete base mat is going across the bottom of the RPV. It can't be accurate. Look at this other one: nei.cachefly.net
The base mat is under the RPV (we can't see it because the torus covers the view to the base mat). The base mat is a square or rectangular concrete shape that is meant to hold the core in the case of a RPV breach. On the other diagram further down that you posted before it is clearly under the line of water.
by Pedro Jesus via Nei.cachefly.net 9/24/2011 2:54:53 PM

@Pedro Jesus everything I have found including the elevation drawing show it where it is on the elevation drawing. The description of Peach Bottom, that has a containment like FUKU put it above the torus and just below the torus downward vent pipes. The elevation drawing has reference points for grade and height. I would take that over a non-measured not to scale illustration intended to just explain structures.
by lillymunster 9/24/2011 2:57:35 PM

If the drywell floor was below that water line the torus wouldn't work right, the downward pipes would be sideways rather than an angle down.
by lillymunster 9/24/2011 2:58:23 PM

Here is tepco's evaluation on corium location in www.kantei.go.jp : "When we regained temperature measurement in various locations, those of reactor
pressure vessels were above 400 degrees Celsius in multiple measuring points. At that
time, though the condition of insufficient cool-down to the reactor core had continued,
they have then sufficiently cooled down since we injected water through the feed-water
line and, due to the secured water injection to the reactor, temperatures in each part
rapidly decreased.
In addition, as a result of calibration of the water-level gauge, we have found that
the water level in reactor pressure vessel is not in the fuel range.
On the other hand, most of the fuel is believed to be cooled in the reactor pressure
vessel, because we can still measure temperatures in CRD housing, etc. at the lower
reactor pressure vessel (if the reactor pressure vessel is breached, we may not be able to
measure temperatures) and temperatures of the steel of the reactor pressure vessel
currently change around between 100 degrees Celsius and 120 degrees Celsius and
correlate changes in amount of water injection in multiple measuring points and
temperatures in multiple points of the upper reactor pressure vessel are higher and the
heat source is estimated to come from the inside of the reactor pressure vessel.
Hence, according to the analysis and plant parameters (temperatures at the
periphery of the reactor pressure vessel), the reactor core has been significantly
damaged, relocated below or slumped to the lower plenum from the fixed position of fuel
loading, however, most of it is being stably cooled down around there."
by Peter 9/24/2011 3:04:56 PM