Published: October 12th, 2012 at 11:39 am ET
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(Subscription Only) Title: TEPCO succeeds in taking water sample from crippled No. 1 reactor
Source: Kyodo
Date: Oct. 12, 2012
The operator of the crippled Fukushima Daiichi nuclear power plant succeeded Friday in taking a sample of water from the No. 1 reactor’s primary containment vessel, the first such attempt since the accident at the plant occurred last year.
Considering the water’s radiation level and other data, Tokyo Electric Power Co. said the fuel, which is believed to have melted through the pressure vessel and accumulated in the outer primary container, does not appear to be releasing large amounts of radioactive substances because it is kept cool.
The water contained 19,000 becquerels of cesium 134 per cubic centimeter and 35,000 becquerels of cesium 137, lower than the density levels of the water accumulating at the building housing the reactor.
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The water is more radioactive outside the Primary Containment Vessel than inside — then where is the melted fuel more likely to be, outside the PCV or inside?
Nuclear Engineer Arnie Gundersen on Unit 1 in July 2012: “Tepco ran a probe into the basement of Unit 1. This is not inside the containment, this is outside the containment. On the top of the water surface they found lethal radiation, 1000 rem an hour. But then they put the probe down into the water and what’s even worse is the bottom, the sediment on the bottom, was thousand of times hotter than that. And what that indicates is that fuel, nuclear fuel, has left the containment, as particles, and settled out on the bottom outside the containment.”
Also consider these recent reports:
- Mystery Continues: 'Difficult to determine' location of melted fuel during Unit 1 investigation, says Tepco -- Radiation dose highest at top of containment vessel
- Asahi: "Radioactive material may be flowing differently" at Fukushima Unit 1 -- Survey results opposite of what Tepco expected
Published: October 12th, 2012 at 11:39 am ET
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sending...
This news — combined with the decreasing level of radiation from top to bottom in the PCV — makes me think the fuel never melted through the RPV.
Some amount of fuel got out of the RPV somehow (RPV broken piping and steam?) and landed on the PCV wall, in top-down fashion.
The continued pumping of water has apparently diluted the radioactive particles at the bottom of the PCV. The PCV must be leaking water somewhere near the top of the torus downcomer, because that matches the current level of the water (i.e., the torus appears intact).
What TEPCO is discovering is strange only if one assumes that there was an RPV melt through in Reactor 1.
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According to Gundersen in July 2012, the water outside Unit 1's containment is so radioactive it "indicates that nuclear FUEL HAS LEFT THE CONTAINMENT, as particles, and settled out on the bottom OUTSIDE the containment".
Today's news appears to confirm his statement, as the radioactivity inside the PCV is lower than outside.
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Puzzling… radiation increases going up the containment… so the fuel went up and out somehow?
I had always assumed a melt through, which is bad enough. But the thought of the reactor exploding like a volcano (as opposed to "just" a hydrogen explosion in the building) is horrific.
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Gundersen: Top lifted off Reactor No. 1 containment BEFORE explosion? (VIDEO)
http://enenews.com/fairewinds-nuclear-expert-believes-top-lifted-off-reactor-no-1-containment-before-explosion-video
Former Fukushima Daiichi Worker: My best guess is explosion had to blow lid off pressure vessel at Reactor 1
http://enenews.com/former-fukushima-daiichi-worker-my-best-guess-is-explosion-had-to-blow-lid-off-pressure-vessel-at-reactor-1
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Wow… just wow. So it blew its top and ejected the core, or some portion of it, possibly preventing a melt through. Thanks for the info.
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Arnie is not saying it blew its top off. He is saying the lid leaked and it is not the reactor vessel lid being talked about but the primary containment lid leaking.
So the real question is, if the (3) reactors were vaporizing their cores during the meltdowns, how much of the cores vaporized and escaped into the environment? Or how much of the cores are left at the site?
So far, only theory has Unit 3's fuel pool ejecting physical fuel assemblies during an explosion.
Not a good choice between having solid plutonium laying around or vaporized plutonium airborne.
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Nuclear Plants And Radioactive Water Contamination; via A Green Road http://agreenroad.blogspot.com/2012/04/nuclear-plants-and-radioactive-water.html
Depleted Uranium Effects In The Human Body; via A Green Road http://agreenroad.blogspot.com/2012/03/depleted-uranium-effects-in-human-body.html
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I also wonder if the earthquake somehow broke some of the fuel rods in Reactor 1, sending them down further in the RPV and keeping them covered in water longer. That could explain why a melt through did not occur, even though Reactor 1 supposedly went the longest without water.
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The reactor bottom itself is the coolest. Outside the reactor in the basement and parts of the outside of the reactor vessel are the highest readings with lethal readings in the basement. So, fuel DID leave the building. Fuel probably also exploded up the mouth of the reactor, and since the lid was lifted, some ejected. Even TEPCO has said Unit 1 has melted through.
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Yes, that is what I'm thinking now after following the links that were given to me. I didn't have all the information before.
Pressure probably built up in the RPV, then its lid blew off or dislodged and corium ejects causing the "golden" goo we see from TEPCO's recent investigation. Pressure then decreases in RPV and builds in PCV. PCV lid then lifts and pressurized air escapes, dragging whatever it can with it on the way out. Hence the low radiation at the bottom of PCV and higher radiation as you go up.
Reactor 2 is a certain melt through. Radiation increases the lower you go in the reactor. But did Reactor 3 repeat what happened in Reactor 1, at a larger scale?
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http://beforeitsnews.com/environment/2012/10/radiation-spreading-east-and-south-across-mainland-usa-2450544.html
Check this out, I spotted this last week. It’s the top story at “Before it’s News”
If you follow the links, you can click on spots on the USA maps and get the radiation readings, so far, right around Wisco/Illinois everything looks pretty normal.
Nothing to panic on here, just the same old things of proper living in the modern world
1) Antioxidants (lots of vitamin C as the cheapest easiest way, no need to get “tricky” with this one)
2) HEPA filters in your house, 3 or 4
3) Stay out of the rain, unless proven (i.e. Geiger counter) that the rain is not radioactive.
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Corium pudding and Admin.: Notice in this blueprint of Reactor1 that the pipes that lead from Containment1 to the Torus enter the Containment slightly above floor level.
http://www.houseoffoust.com/fukushima/blueprint.html
Some of the corium has run down into these pipes, and melted through the steel Torus. But the majority of Corium1 (tens of tons) sank directly into the floor of Containment1, and ate its way through the Building1 concrete into the mudrock below. The corium did not exit Reactor1 explosively, up and out of Building1. Else readings around the plant would still be off the charts. Instead, corium ate its way out the bottom of the RPV, and out the bottom of Containment1. The top of Containment1 is highly radioactive because of the heavy coating of precipitated uranium, etc. from the meltdown. The water isn't highly radioactive because they keep pumping FRESH water into Containment1, which only comes into contact with residual corium left on the bottom of Containment1. Some corium exited Containment1, and melted out of the bottom of the Torus onto the flooded basement floor. This corium has made the water in the flooded Torus Room very radioactive, which is Gundersen's observation. Let's not forget what we now know to be the truth.
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Great summation, PhilipUpNorth. Though, isn't it possible that there was enough explosive reaction to eject some vaporized fuel along the mouth of the reactor and through the lid that was either jarred loose from an earthquake or from the explosion? But, another option for the radioactivity up top might be from the venting through the vent stack with the scrubber they placed on the building after the explosion.
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Philip,
I don't know what the real story is because there aren't enough facts yet. I get your point about the water cleansing the reactor on the way down. What I don't get is the water level in Reactor 1 that TEPCO reports and your theory that corium melted through the Torus.
If corium did indeed melt through the Torus, how can the water level that TEPCO reports be precisely at the top of the downcomer pipe into the Torus? Is TEPCO pouring in water fast enough to keep it at that level, or is the water level outside the melted-through Torus high enough so that the level inside the PCV is matching it?
Water will flow out of a broken Torus if it can… the only thing to stop that is to 1) have the water level outside the Torus match the inside of the PCV or 2) have the Torus be intact, except for a leak somewhere above the downcomer piping.
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you and your corium as one burning mass.
the zirconium melted , the fuel had contact with water (steam and or liquid) and then there was to much water around to allow melting, innstead the fuel crumbled away. not less deadly but just dispersed, not one meltthrough blob.
it is in some way natural that the uper part is hotter as the water is a very good paticle catcher. (steam washes a lot stuff down, makes sense)
what makes me wonder after visiting again after weeks, the near containment chambers are empty? are they still pumping in tons a day? what about the huge amount of to-be-cleand water and the waste resulting from cleaning?
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I think pumping in boron laced water and collecting it for scrubbing along it's recirculation path is still ongoing in hundreds of tons on a daily basis. They have added a high level incinerator and the water from Unit 4 in the basement is currently going into that for burning and reducing. Some water on site is allowed to run off into the Pacific Ocean once it is scrubbed or considered low level radiation (just hate that!). I'm not sure which buildings hold water better, but, i believe that they all leak to some degree, the heat of the reactors vaporizes much of the water, but, recirculating pumped water that has been scrubbed is the only current method of cooling the reactors and SFP's and this method is what allowed TEPCO to say that they achieved "cold shut down", which they were forced to reword as "cold stable" or some such phrase. There are buildings and a barge that contain radioactive water waiting for processing. When these get too full, the spillover is released into the ocean or, when possible, the vessels of scrubbed water are emptied into the sea to make more storage room for more highly radioactive water. It is my understanding that this method will continue as the primary response throughout the entire decommissioning of the reactors since there is no other way to cool them given their state of damage. That's about 50 years or more if all goes well. If i remember correctly, the source of the water now is desalinized sea water.
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Radiation probes indicate NO melt through at Fukushima Unit 1
hahahaha.. oh the good news..
"Tepco has recently released measurements that provide convincing evidence that virtually all of the corium in Fukushima Daiichi unit #1 remains safely stored inside an intact reactor pressure vessel. Despite all claims to the contrary, no substantial quantities of that material have melted through the pressure vessel to fall onto the concrete floor of the surrounding containment structure.
It has always seemed far fetched to me to think that material from a nuclear reactor that melted several hours after fission has stopped contains the power density necessary to melt through carbon steel pressure vessels that are 6-12 inches thick."
Consider the source.. Rod Adams
Rod Adams gained his nuclear knowledge as a submarine engineer officer and as the founder of a company that tried to develop a market for small, modular reactors from 1993-1999.
sheez
://theenergycollective.com/rodadams/124446/radiation-probes-indicate-no-melt-through-fukushima-unit-1
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