- #13,091
MadderDoc
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What, if anything, could have been a _technical_ rationale of Tepco of letting firefighters risk their lives to splash water to the top of Unit 3 in the days following March 16th 2011?
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MadderDoc said:What, if anything, could have been a _technical_ rationale of Tepco of letting firefighters risk their lives to splash water to the top of Unit 3 in the days following March 16th 2011?
MadderDoc said:Then of course, it could be the measured PCV pressure readings in unit 3 which are erroneously too high during this period, rather than the RPV's pressure readings too low.
zapperzero said:The real and present danger of pool dry-out of course. We've been over this before, if from a different angle - the firefighting helicopters found multi-Sievert/h fields above unit 3, suggesting either massive gas/particulate releases (unlikely, for a variety of reasons) or shine from a mostly empty pool.
zapperzero said:Common sense would suggest that whichever is closest to atmospheric is true, fwiw.
MadderDoc said:Those high radiation fields were measured, I believe, on March 16th, on which day there was massive steam release from the building -- Tepco evacuated their own people temporarily out of fear that the PCV was leaking, and videos were taken from helicopters showing steam sources to be consistent with that fear. Otoh, there does not seem to have been any cause on that day to think the pool was even boiling.
Therefore I do not find it readily credible that Tepco the next day should have thought the danger of dry-out of the pool of unit 3 was real and present to a degree of imminence that the brave people of the civil forces should think they had cause to be willing to risk their lives in desperate measures to splash just some water into it.
zapperzero said:They weren't expecting that water to make it into the PCV, no? So what else is left? A fire (for which there is no evidence whatsoever) or a pool that is _believed_ to be emptying fast.
MadderDoc said:Please explain.
MadderDoc said:But you can't just assume that they did have a technical rationale relating to conditions of the plant.
It is well known that people may act out of a variety of motivations. [/ quote]
I don't really buy the "they did this to be seen doing something" idea anymore. Something WAS being done, quite arduously and visibly in fact. Trucks and pumps were moving in, power lines were being repaired etc etc.
For what we know there was as little evidence that the pool was emptying fast, as there was of a fire.
No. There was a simple calculation as to how long it takes for the pool to boil after the pump stops. There was also an elevated and increasing, but rather uniform radiation field around Unit 3 (on the ground), which at least to some must have said"gamma shine".
:-) That is some statement but even if assumed it doesn't follow that this one would have to be.zapperzero said:Why not? Everything else, including the aborted decision to abandon the site, was based on a technical rationale.
Now I didn't suggest Tepco did anything to be seen doing something. Perhaps they did, as I said people are known to act from a diversity of motivations, including this one.I don't really buy the "they did this to be seen doing something" idea anymore. Something WAS being done, quite arduously and visibly in fact. Trucks and pumps were moving in, power lines were being repaired etc etc.
Yes, and no doubt Tepco did the calculation, only the result must've shown that the pool ought to be days from boiling and many days from fuel exposure. You also never heard a Tepco official say the Unit 3 pool was drying out fast. Nor was it expressed at the next level of the foodchain, NISA, who rather thought at the time that the Unit 4 pool was the one in need of urgent attention.There was a simple calculation as to how long it takes for the pool to boil after the pump stops.
To be sure the dose rate was high around unit 3 after the explosion. That just puts some seriousness to the question, what was Tepco's technical rationale for letting people go in there to splash water onto the building.There was also an elevated and increasing, but rather uniform radiation field around Unit 3 (on the ground), which at least to some must have said"gamma shine".
zapperzero said:I'd expect that one vent path or another eventually opened and remained open, so I'd intuitively go for the lower number, when asked to estimate which of the three readings of our steaming teapot is correct.
Moreover, the three sensor readings track each other pretty nicely - except at the initial two peaks, where the RPV pressure is shown as highest (which makes sense, as it could probably still hold pressure at those times). What seems more likely? That the RPV pressure is over-, then under-reported by the same instrument, or that the other two are consistently over-reported?
Yes, and no doubt Tepco did the calculation, only the result must've shown that the pool ought to be days from boiling and many days from fuel exposure.
jim hardy said:i think there's somewhere a tabulation of how much water was added to respective pools.
Perhaps it did/does, but my point is that Tepco at the time of all that display of bravery at unit 3 do not seem to have had any observation to indicate that the pool was leaking, boiling, nor drying out. Tepco also never said anything to that effect, nor did NISA. The rest of the world were excused to think that such desperate measures as shown in the telly would imply a critical situation, but Tepco never said there was a critical situation with the spent fuel pool of unit 3. All they said was the rather obvious, that if the spent fuel pools were to be not served with water, they might eventually dry out and bad things could happen.I had assumed unit 3 pool leaked , because of degree of damage to building from explosion and later videos showing what looked like rebar bent into pool.
I was among those thinking at the time #3 pool level was low and gamma backscatter was reason for high fields on ground. Lots of makeup water compared to others would support that.
MadderDoc said:I have a note of a tabulation from Tepco, saying that as of the morning of April 1, 90 tons had been applied to SFP1, 4802 tons to SFP3, and 1278 tons to SFP4. There was no figure for SFP2 in that source according to my note. The figure for Unit 3 would have included helicopter dumps and much building splashing.
Tepco, unlike the fire-fighters, cannot be assumed to have not realized from the helicopter observations and videos on March the 16th, that there was water in the pool and it was not boiling.
gnasch said:I remember reading shortly after the helicopter water drops that japanese officials put this into the context of "calming the americans", presumably upon the impression of Mr. Jaczko going ballistic over the pools and recommending an 80 km evacuation radius. No source remembered though.
SteveElbows said:Personally if I were them I would have started these operations as soon as possible, so as to leave more wiggle room and reduce the chances that other events could get in the way of water spraying by the time it was absolutely necessary.
zapperzero said:This would support the idea that they thought SFP3 was drying fast, no?
The helicopters "saw" a 7.5 Sv/h field at 90 meters above the unit and a smoking or steaming pool filled with rubble. These are not encouraging observations.
SteveElbows said:There certainly is at least one document that goes into full detail about the time & volume of spraying to the pools, but I cannot lay my hands on it right now.
MadderDoc said:According to the WHO, the measured dose rate from the helicopters involved in the water dump operations was t(300m), and 87.7 milli Sv/h at 300ft (90m). As regards what could be seen from helicopters, we can get some indication from the published video sequences that were shot on March 16th. They appear to show a water surface in the pool, and steam plumes originating from areas close to the pool gates on either side of the reactor well. That was probably also what a human observer would have seen from the helicopter, only more clearly
zapperzero said:I took the 7.5 Sv/h figure from a NRC transcript. I posted the transcript here earlier.
EDIT: The WHO numbers are for the water spraying mission on the 17th.
www.u-tokyo-rad.jp/data/whositrep.pdf
MadderDoc said:The transcript has the figure as 375 R/h actually. Quaint unit that, Roentgen per hour. Still, (assuming this is gamma) 3.75 Sv/h is a very high dose rate. which could call for a reality check.
zapperzero said:My bad. My treacherous memory doubled it and I don't know why :P.
SteveElbows said:<.>
I know that many months ago some attention was paid to why video of one of the firefighter missions showed someone spraying the wrong side of the building.
I don't have a wonderful explanation for this, although I wouldn't read too much into it, especially as the ground between units 3 & 4 was not very hospitable at the time.
MadderDoc said:Actually, Steve, there is no evidence that the fire-fighters sprayed to the side of the building where the pool is, on any of their missions. It may seem strange to us, however the fire-fighters would have thought their target was somewhere there in the middle, where the steam was coming from.
jim hardy said:if RPV found a path to atmosphere but torus remained pressurized?
elektrownik said:Bad source of information but data looks legit. What could be the source of I131 ?
http://fukushima-diary.com/2012/05/iodine-131-measured-in-kawasaki-yokohama-chiba-and-gunma/
http://fukushima-diary.com/2012/05/iodine-131-measured-in-yamanashi/
http://fukushima-diary.com/2012/05/iodine-131-measured-in-tokyo/
SpunkyMonkey said:Exactly, here the firemen were, reportedly watering the fuel pool.They seemed to think it was around the NW corner or near the middle of the floor. Why were they so poorly informed? So there those fearless men were risking their health/lives to merely water debris.
Lot's o great analyses going on here, esp re the valve. Am I correct in my impression that it seems the valve was of a type that should have allowed the RPV to re-pressurize if there wasn't a hole in it already? If so, this would seem consistent with the massive RPV pressure collapse on Mar 13 as marking time of melt-through, and exactly fitting the model of Ott et al.
By giving them the necessary data?MadderDoc said:I am not sure how I would go on about informing the fire department -- called in an emergency to stop a spent fuel pool from boiling dry -- that they should direct their attention to a part of the building which was not steaming.
Yes, possibly. According to officialdom nothing really was achieved, nor could have been achieved, except for more human radiation exposure. In my book this would put the acts of the firefighters in the helpless category, and that of their superiors in the bandit-like. I must apologize if I have come over by my expression, as implying that either of them were stupid, or acting stupidly, I didn't mean to.Rive said:If they have aimed the plumes then they did it for a reason.
SpunkyMonkey said:Exactly, here the firemen were, reportedly watering the fuel pool.They seemed to think it was around the NW corner or near the middle of the floor. Why were they so poorly informed? So there those fearless men were risking their health/lives to merely water debris.