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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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SpunkyMonkey
#13141
May4-12, 11:24 AM
P: 65
Quote Quote by SteveElbows View Post
Actually thats the one example of footage where it always looked to me like they were trying to spray the right part of the building (but mostly falling short).
Possibly the high-dose rate on the south side (imo prob caused by the stack-vent bursting on the south side and releasing lots of cesium-vapor residue) which should have been detectable by the first Geiger counter in the scene made them opt to try to reach the pool from the NW corner.
SpunkyMonkey
#13142
May4-12, 12:04 PM
P: 65
Quote Quote by MadderDoc View Post
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.
At the time, it may not have been clear from the helicopter footage that the pool wasn't largely empty. It's only with the data gained over the following weeks that we could thereafter determine that there were roof girders / materials in the pool that were obscured by water on the 16th. But on the 16th they didn't have that information about debris in the pool.

Although U3 pool didn't seem to be steaming at that time, whereas U4 pool was steaming vigorously. Perhaps that invoked fear that U3 pool was a deep dark hole with no water left to boil.

Thanks for the overview of the valve analysis!
MadderDoc
#13143
May4-12, 12:28 PM
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Quote Quote by SpunkyMonkey View Post
At the time, it may not have been clear <..>
That is simply not credible. Tepco shot more video footage than we've been shown, and of better quality, and they had an employee on board the helicopters sent there with the specific assignment by combined Tepco and Japanese Government order to assess the water levels of the pools.
MadderDoc
#13144
May4-12, 12:39 PM
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Quote Quote by SpunkyMonkey View Post
Here are some thoughts on the Unit 3 1st floor PVC shield plug being moved from Genn Saji, former Secretariat of Nuclear Safety Commission, Japan:
I would like to see it in context. "Spontaneous venting" ?
MadderDoc
#13145
May4-12, 01:17 PM
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Quote Quote by SpunkyMonkey View Post
<..>
Although U3 pool didn't seem to be steaming at that time, whereas U4 pool was steaming vigorously. Perhaps that invoked fear that U3 pool was a deep dark hole with no water left to boil.
Iffy. Tepco said on the press conference that day that the steam from the Unit 3 building had been found to be coming from the pool, not the reactor.
SpunkyMonkey
#13146
May4-12, 02:02 PM
P: 65
Quote Quote by MadderDoc View Post
I would like to see it in context. "Spontaneous venting" ?
He's also taken the view that there was a PCV overpressure event(s) accounting for the ajar hatch plug. As much as that happily fits with my theory, how do we explain the small lightweight objects in the hatch passageway? I'd expect they should have been blown out of the passage had a huge impulse blasted through it. Or maybe they were dropped during an earlier but recent inspection of the passageway. We probably shouldn't expect to find them in the passageway anyway if when the plug is closed it fits with perfect tightness.

But something certainly made the first floor a mess, exactly matching a hurricane-like wind blowing through it. So everything fits for an overpressure blowing through, minus those two tiny objects in the purported blow path.

ADD: I think by "spontaneous venting" he means caused by a series of small explosions(?) in the PCV. It seems a bit of a stretch to correlate the radiation readings on campus to these hypothetical events in Unit 3, but it also seems like an interesting idea.

Tepco shot more video footage than we've been shown, and of better quality,
Is that known or assumed? I'd suspect so myself, but I don't know so. We're taking about around April 16, 2011 of course.

What is it that you're getting at, if anything, with this line of inquiry? Are their plausible motives to mislead the public that they were worried about pool 3 being dry?
LabratSR
#13147
May4-12, 02:18 PM
P: 176
I didnt see this posted yet. Sorry if it has been already.


April 23 Fukushima Unit 4 Walkthrough
http://youtu.be/qZOqyEzhGGQ
MadderDoc
#13148
May4-12, 03:00 PM
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Quote Quote by SpunkyMonkey View Post
<..>
Is that known or assumed? I'd suspect so myself, but I don't know so. We're taking about around April 16, 2011 of course.
I assume you meant to write March. The press kit from March 16 included a reasonable quality still from a non-published video sequence.
What is it that you're getting at, if anything, with this line of inquiry? Are their plausible motives to mislead the public that they were worried about pool 3 being dry?
The latter question would seem to be OT. My inquiry is directed at finding Tepco's technical rationale for letting people risk their lives to splash some water onto unit 3.
jim hardy
#13149
May4-12, 03:33 PM
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Tepco said on the press conference that day that the steam from the Unit 3 building had been found to be coming from the pool, not the reactor.
which led me to assume pool was low on water. If full it should have considerable thermal capacity and be not steaming yet ?
Per m'doc's post 13115 two pages back its decay heat load was only ~half megawatt.


Cross section, probably a generic drawing, looking toward ocean and pool appears on right


drawing looking West (toward land), pool appears on left side as in helicopter video


Cracks in the pool wall on reactor side (from PCV flexing ? ) would leak pool water into basement ?
That's the pool that got 4800 tons of water.
Almost 4X as much as unit 4 got(1278). But 4's pool has 5X the heat load of 3's.

As you said - i should look for something that destroys that hypothesis not supports it.

old jim
MadderDoc
#13150
May4-12, 04:08 PM
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Quote Quote by jim hardy View Post
Cracks in the pool wall on reactor side (from PCV flexing ? ) would leak pool water into basement ?
That's the pool that got 4800 tons of water.
Almost 4X as much as unit 4 got(1278). But 4's pool has 5X the heat load of 3's.

As you said - i should look for something that destroys that hypothesis not supports it.

old jim
On SFPs, tsutsuji posted a while back, a translation of a part, and a link to the original document:
http://www.physicsforums.com/showpos...ostcount=12587

I did a quick BOE reality check of the data given there of the refill demand rate of SFP3 during concrete pump injection, and fwiw found it to be consistent with the decay heat of the pool.
SpunkyMonkey
#13151
May4-12, 04:10 PM
P: 65
Quote Quote by MadderDoc View Post
I assume you meant to write March. The press kit from March 16 included a reasonable quality still from a non-published video sequence.
Right, I meant March. Could it be a photo (not video frame) you refer to? I think for safety the helicopter avoided a direct flyover, so I'm not sure they got much closer than we've seen.

The latter question would seem to be OT. My inquiry is directed at finding Tepco's technical rationale for letting people risk their lives to splash some water onto unit 3.
But you seem to be arguing that they had to know the pool wasn't dried out or close thereto, and yet to the contrary were saying that's what they thought. Btw, I'm not against considering if Tepco's been less than honest. There's a well-known history of coverups and evasion in Japanese nuclear industry that includes Tepco. The level of public scrutiny they're under now is probably the best deterrent, but we shouldn't assume it's an ironclad safeguard.
jim hardy
#13152
May4-12, 07:14 PM
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As the full water level was reached when half the predicted quantity of water had been used, it was confirmed that the predictions of evaporated quantities made until then had been conservative, and that more water had been injected than the needed quantities. Among the quantities that were injected until then, it is thought that the surplus overflowed. After the water injections that were inferred as having generated overflows, although the causal relationship is unclear, a phenomenon where the temperature in parts such as the bellows seal, rises and declines within a short time was observed.
Thanks doc i had missed that one.
MadderDoc
#13153
May4-12, 08:39 PM
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Quote Quote by SpunkyMonkey View Post
<..>you seem to be arguing that they had to know the pool wasn't dried out or close thereto, and yet to the contrary were saying that's what they thought.
Then I may not have expressed myself clearly.

I have been arguing that from the evidence Tepco has shown me, there would seem to have been no basis for the thought that the pool was dried out or close thereto, and that Tepco in consistence with this also never said that's what they thought.
MadderDoc
#13154
May5-12, 02:52 AM
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Quote Quote by SpunkyMonkey View Post
Could it be a photo (not video frame) you refer to? I think for safety the helicopter avoided a direct flyover, so I'm not sure they got much closer than we've seen.
While not having an assumed source video I cannot definitely say that an image is a frame from it. However, in the press kit, one image is an exact replica of a frame from one of the published videos, only the image is of more than double the pixel resolution as that of the frame from that video. The other images included in the press kit are of the same higher pixel resolution, but they do not match any frames of the published videos, while otoh, they do show signs of compression artefacts of a type I would expect to find in a video, but not in a jpeg compressed image produced by a camera. That's why I think the videos of the press kit are of poorer quality than the original, and that there is unpublished video footage.
MadderDoc
#13155
May5-12, 03:09 AM
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Quote Quote by jim hardy View Post
Thanks doc i had missed that one.
I'll send that straight on to tsutsuji who made the translation, who drew our attention to the existence of the document. Thanks tsutsuji!

Interesting observation there, btw, would like to know more about this possible 'high tide' communion between the pool and the reactor internals:
"After the water injections that were inferred as having generated overflows, although the causal relationship is unclear, a phenomenon where the temperature in parts such as the bellows seal, rises and declines within a short time was observed. "
westfield
#13156
May5-12, 09:21 AM
P: 145
Quote Quote by jim hardy View Post
<snip>
So if the pressure tap were near top of vessel and the sensor lower than that,
when sensing line dried out,
reported pressure would be low by the height of fluid lost.

but i dont know physical arrangement in a BWR. Mine i knew pretty well.

old jim
I'm a little late re the SRV & Instumentation posts.

This document may be a useful reference, I had been searching for Duane Arnold Energy Centre drawings for some time as it seems to be one of the closest USA BWR types to fukuichi U2 & U3.
Very similar RB & TB layout. It took quite some time to find any drawings at all.
Of course there will be differences between the plants but these are the closest I've found so far.

Some of the drawings that may be of interest to you Jim are:
(They don't really help you out with the physical relationship of tap and sensor locations though)

Page 10 - P & ID - Nuclear Boiler System
Page 11 - P & ID - Reactor Vessel Instrumentation
Page 67 & 68 - P & ID - Main Steam
westfield
#13157
May5-12, 11:17 AM
P: 145
Quote Quote by zapperzero View Post
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.
In general reply to the question of what the fire dept might have been attempting to do.

This is a little out there.....but so is trying to spray the pool from the NW corner of U3 with a fire truck.
The D\S pool has no watertight gate between it and the reactor void, water could flow through the concrete shield segments from the D\S pool down into the upper part of the void and onto the PCV head. Could Tepco have been trying to cool or cover the top of the PCV not the SFP?
jim hardy
#13158
May5-12, 11:58 AM
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"After the water injections that were inferred as having generated overflows, although the causal relationship is unclear, a phenomenon where the temperature in parts such as the bellows seal, rises and declines within a short time was observed. "
that kinda sticks out, doesn't it?

Did they not inject some concrete into that pool? One wonders where.

Sure sounds like water running over the wall down onto flange-bellows area.
Pure guess though.

Thanks Westfield for the links to DAEC
will look at them this evening
small world - my former employer bought that plant.

And if Tsutsuji needs anything i could send, pm me a mailing address.


old jim


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