Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
TCups
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#3457
Apr11-11, 04:23 PM
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Quote Quote by |Fred View Post
Considering that at d + almost 30 , they aren't any closer to restore cooling , if anything situation is worse , containment is not really containing , what option do they have ? They can't let it bleed out for ever ...
An interesting question, indeed. Posited another way: If the emergency efforts to cool the reactor cores are (and it would seem, can only be) a temporary solution as long as the coolant (water) is not contained in a closed system,

Then only three alternatives exist:

1) Continue to spill contaminated water and slowly (relatively) contaminate the ground water and ocean while temporizing. (possibly, to allow time to deal with the spent fuel in the SFPs?), or

2) Somehow devise a stable, permanent system to contain, decontaminate and if possible, recirculate the water being used for cooling the cores (unlikely), or

3) Prepare to let the cores melt and deal with the consequences.

Is there another option I am missing? If not, then option (3), it seems, is most likely the "not if, but when" final event in the Fukushima disaster sequence.

Which begs the question: What might be done while temporizing with the current efforts to cool the cores to mitigate the ultimate consequences of one or more melted reactor cores with loss of the primary containment? If the answer to that question is "nothing effective", then, is option (1) with ongoing contamination by un-contained, highly contaminated water for as long as humanly possible worse than option (3)?

I don't know.
bytepirate
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#3458
Apr11-11, 04:39 PM
P: 61
Quote Quote by Astronuc View Post
Here is another good overview of the Fukushima event.
http://www.vgb.org/vgbmultimedia/New...himav15VGB.pdf
a good overview, but:
"Recriticality in Unit 2 ?
(according to soil samples,
might explain radioactivity spike on march 16)"

is there *any* evidence for a recriticality in #2?
the spike on march 16th could be much better explained by (undetected??) melting/burning fuel in #4 SFP (imho):
there was an explosion before:
http://www.tepco.co.jp/en/press/corp...1031504-e.html
and a fire afterwards:
http://www.tepco.co.jp/en/press/corp...1031606-e.html
and in the meantime, the (then uncooled) fuel took a nap?
AntonL
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#3459
Apr11-11, 04:51 PM
P: 521
Quote Quote by TCups View Post
3) Prepare to let the cores melt and deal with the consequences.
a core melt might be a cleaner solution than a continues feed and bleed, only if it can be guaranteed that the molten core does not go critical, and to prevent a steam explosion the dry well must dry which it is not.
biscuitcheese
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#3460
Apr11-11, 04:56 PM
P: 12
Quote Quote by TCups View Post
An interesting question, indeed. Posited another way: If the emergency efforts to cool the reactor cores are (and it would seem, can only be) a temporary solution as long as the coolant (water) is not contained in a closed system,

Then only three alternatives exist:

1) Continue to spill contaminated water and slowly (relatively) contaminate the ground water and ocean while temporizing. (possibly, to allow time to deal with the spent fuel in the SFPs?), or

2) Somehow devise a stable, permanent system to contain, decontaminate and if possible, recirculate the water being used for cooling the cores (unlikely), or

3) Prepare to let the cores melt and deal with the consequences.

Is there another option I am missing? If not, then option (3), it seems, is most likely the "not if, but when" final event in the Fukushima disaster sequence.

Which begs the question: What might be done while temporizing with the current efforts to cool the cores to mitigate the ultimate consequences of one or more melted reactor cores with loss of the primary containment? If the answer to that question is "nothing effective", then, is option (1) with ongoing contamination by un-contained, highly contaminated water for as long as humanly possible worse than option (3)?

I don't know.
I dont know what the sea depths are near the plant, or what kind of logistic/financial nightmare it may be, but why couldnt they hire or buy a bunch of oil tankers to sit off the coast to facilitate easier siphoning of contaminated water from the plant to the oil tankers as an expendible temporary storage solution for the contaminated water?

It seems to be better than purposely dumping what is already collected/contained radioactive water into the ocean because 'they had no choice'. If it was an uncontrollable leak thats one thing, but if their problem is with storage (and it seems to be the case earlier with the purposeful dumping), then there are obvious solutions that can be had like hiring/buying oil tankers to store the water.
Pheesh
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#3461
Apr11-11, 04:57 PM
P: 5
Well it's now basically official, I guess they just felt like skipping 6!
The Japanese government's nuclear safety agency has decided to raise the crisis level of the Fukushima Daiichi power plant accident from 5 to 7, the worst on the international scale.

The Nuclear and Industrial Safety Agency made the decision on Monday. It says the damaged facilities have been releasing a massive amount of radioactive substances, which are posing a threat to human health and the environment over a wide area.
http://www3.nhk.or.jp/daily/english/12_05.html
biscuitcheese
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#3462
Apr11-11, 05:10 PM
P: 12
Quote Quote by Pheesh View Post
Well it's now basically official, I guess they just felt like skipping 6!

http://www3.nhk.or.jp/daily/english/12_05.html
It baffles the mind how many so called 'experts' were on the news early in this disaster, who were adamant that the still developing situation could not possibly be worse than the TMI incident and that a disaster rating above 4 was impossible.

It seemed so obvious right from the very start the accident was worst than TMI because (1) there was reportedly a hydrogen explosion which for all intents and purposes can likely only occur if fuel rods were overheating leading to thermolysis of water catalysed with the zirc-water reaction to generate the hydrogen in the first place, and (2) the military subsequently detected I and Cs radioisotopes off the coast that obviously came from the reactor likely due to pressure releast from primary containment. Ultimately though, the facts have already demonstrated long ago that core overheating happened (likely with fuel cladding melting also since they didnt get cooling in there for a long time) and also that radioactive elements were already released into the atmosphere thus proven very early to be worse than TMI since TMI had fuel melting but no substantial amount of radioisotopes were released into the atmosphere and that there was no indications of breach in containment (not even the outer containment) for which was certainly not the case in the fukushima incident.
bytepirate
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#3463
Apr11-11, 05:12 PM
P: 61
Quote Quote by TCups View Post
An interesting question, indeed. Posited another way: If the emergency efforts to cool the reactor cores are (and it would seem, can only be) a temporary solution as long as the coolant (water) is not contained in a closed system,

Then only three alternatives exist:

1) Continue to spill contaminated water and slowly (relatively) contaminate the ground water and ocean while temporizing. (possibly, to allow time to deal with the spent fuel in the SFPs?), or

2) Somehow devise a stable, permanent system to contain, decontaminate and if possible, recirculate the water being used for cooling the cores (unlikely), or

3) Prepare to let the cores melt and deal with the consequences.

Is there another option I am missing? If not, then option (3), it seems, is most likely the "not if, but when" final event in the Fukushima disaster sequence.

Which begs the question: What might be done while temporizing with the current efforts to cool the cores to mitigate the ultimate consequences of one or more melted reactor cores with loss of the primary containment? If the answer to that question is "nothing effective", then, is option (1) with ongoing contamination by un-contained, highly contaminated water for as long as humanly possible worse than option (3)?

I don't know.
maybe they need a feynman (or any other brilliant mind, preferred alive) to come up with an unexpected fourth solution.
something like:
fill up the RPV with copper pellets, then pour in some radiator sealant (i have heard pepper and eggs are working), then cool the thing from the outside.

this is not a serious suggestion, but maybe the final solution will be something like that: unexpected, ridiculous - and working.
83729780
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#3464
Apr11-11, 05:32 PM
P: 31
Quote Quote by TCups View Post
Is there another option I am missing?
I honestly think they're still considering the giant cloth. It's been mentioned twice in Kyodo news reports.
Borek
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#3465
Apr11-11, 05:44 PM
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Quote Quote by |Fred View Post
Considering that at d + almost 30 , they aren't any closer to restore cooling , if anything situation is worse , containment is not really containing , what option do they have ? They can't let it bleed out for ever ...
Amount of heat evolving should be getting down, even if there are short criticalities. Once the power gets down they can stop cooling. But I doubt there is much that can be done earlier.
StrangeBeauty
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#3466
Apr11-11, 06:12 PM
P: 61
Pardon if this is a repost: They've issued corrections to a number of released readings/info including pressure readings for RPVs #1 and #3:

http://www.nisa.meti.go.jp/english/f...20110411-3.pdf

[Edit]: There appears to be some new data for #3
shogun338
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#3467
Apr11-11, 07:01 PM
P: 133
A fire broke out at Japan's crippled Fukushima Daiichi nuclear power plant, operator Tokyo Electric and Power (TEPCO) said on Tuesday, although flames and smoke were no longer visible. http://www.reuters.com/article/2011/...7FB1YD20110411
shogun338
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#3468
Apr11-11, 07:05 PM
P: 133
Magnitude 6.6 - EASTERN HONSHU, JAPAN
2011 April 11 08:16:13 UTC http://earthquake.usgs.gov/earthquak...11/usc0002n9v/
Astronuc
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#3469
Apr11-11, 07:35 PM
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They just had a mag 6.2 down near the Tokai plant.
http://earthquake.usgs.gov/earthquak...usc0002nzx.php
Date-Time:
Monday, April 11, 2011 at 23:08:16 UTC
Tuesday, April 12, 2011 at 08:08:16 AM at epicenter

Location: 35.406N, 140.542E
Depth: 13.1 km (8.1 miles)

Distances:
77 km (47 miles) ESE of TOKYO, Japan
82 km (50 miles) E of Yokohama, Honshu, Japan
106 km (65 miles) S of Mito, Honshu, Japan
140 km (86 miles) SSE of Utsunomiya, Honshu, Japan
shogun338
shogun338 is offline
#3470
Apr11-11, 08:48 PM
P: 133
RPV temperatures remain above cold shutdown conditions in all Units, (typically less than 95 C). In Unit 1 temperature at the feed water nozzle of the RPV is 228 C and at the bottom of the RPV is 121 C. In Unit 2 the temperature at the feed water nozzle of the RPV is 149 C. The temperature at the bottom of the RPV was not reported. In Unit 3 the temperature at the feed water nozzle of the RPV is 92 C and at the bottom of the RPV is 111 C. With the temperature being over 428 degrees Fahrenheit at the feed nozzle does this indicate that fission is still occurring inside Unit 1 ? http://www.iaea.org/newscenter/news/...iupdate01.html
SredniVashtar
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#3471
Apr11-11, 09:41 PM
P: 81
They have raised the level to 7
http://www.bbc.co.uk/news/world-asia-pacific-1304534

Japanese authorities have raised the measure of severity of their nuclear crisis to the highest level, officials say.
The decision was taken due to radiation measured at the damaged Fukushima Daiichi power plant, NHK reported.
"This is a preliminary assessment, and is subject to finalisation by the International Atomic Energy Agency," said an official at the Nuclear and Industrial Safety Agency (NISA)
The decision to raise the threat level was made after radiation of 10,000 terabequerels per hour had been estimated at the stricken plant for several hours.
Astronuc
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#3472
Apr11-11, 09:47 PM
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Quote Quote by shogun338 View Post
RPV temperatures remain above cold shutdown conditions in all Units, (typically less than 95 C). In Unit 1 temperature at the feed water nozzle of the RPV is 228 C and at the bottom of the RPV is 121 C. In Unit 2 the temperature at the feed water nozzle of the RPV is 149 C. The temperature at the bottom of the RPV was not reported. In Unit 3 the temperature at the feed water nozzle of the RPV is 92 C and at the bottom of the RPV is 111 C. With the temperature being over 428 degrees Fahrenheit at the feed nozzle does this indicate that fission is still occurring inside Unit 1 ? http://www.iaea.org/newscenter/news/...iupdate01.html
The temperatures on Unit 1 are puzzling, and the Unit 3 temperatures are problematic.
I_P
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#3473
Apr11-11, 10:23 PM
P: 46
An interesting article providing some details of the first two days of the accident:

http://www.yomiuri.co.jp/dy/national/T110411004567.htm
Bodge
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#3474
Apr11-11, 10:30 PM
P: 145
Confusion reigns in Japan:

11:14 NEWS ADVISORY: Radioactive materials from Fukushima plant 10% of amount from Chernobyl

11:39 NEWS ADVISORY: Fukushima different from Chernobyl, without massive radiation leak: agency

12:09 NEWS ADVISORY: Radiation leak may exceed amount in Chernobyl accident: TEPCO

http://english.kyodonews.jp/news/


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