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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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SkepticJ
#397
Mar17-11, 07:21 PM
P: 251
Quote Quote by kloptok View Post
Situations like these does indeed raise questions of an utilitaristic nature: is it right or wrong for a number of individuals to risk their lives for the survival of many others? Looking at Chernobyl it is clear that a number of persons died while rescuing the situation, probably for the survival of many others.
The needs of the many outweigh the needs of the few.

That suicidal actions aren't being undertaken is pretty damning evidence against those who're screaming that this is another potential Chernobyl-level event. If it was, bucket brigades to the storage pool would be in order.

Japan still has a much more honor-bound culture than Russia, or the United States. If we'd so sacrifice ourselves for the greater good, how much more them?
Astronuc
#398
Mar17-11, 07:35 PM
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Quote Quote by Angry Citizen View Post
What I'm most curious about are the spent fuel ponds. Would the reinstatement of power in the facility allow the ponds to be cooled without having to pump in a continuous stream of fresh water? I'm just fuzzy on whether or not there's an actual cooling system for the spent fuel ponds, or if they just replace the water as it boils off.
Under normal operation, there would be a heat exchanger to cool the water. Water introduced into the primary system and spent fuel pools is extremely clean - cleaner than the water from your home faucets.

There are makeup water systems, but the idea would be keep the water cool with minimal evaporation. Now those systems are contaminated with seawater, as well as whatever fission products dissolved in the water.

The objective would be to fill and cool the containments and spent fuel pools, then close any further release path, and perhaps try to decontaminate the plant area to permit personnel to get start the recovery process. It may take many months, possibly more than a year to get insides the reactors to see what damage has been done. Possibly submerssible robots with rad-resistant cameras will be employed to look in the containment and cores. They have to ascertain the structural damage.

Similarly, the will have to ensure the spent fuel pools are filled, and then send in remotely controlled rad-resistant cameras to see the status of the spent fuel. They will have to devise some temporary shielding.

The damaged/destroyed structures will have to be removed and some interim structures capable of heavy lifting brought in. And an interim fuel handling machine would have to be installed.
AtomicWombat
#399
Mar17-11, 07:51 PM
P: 150
Here is an English language version of the video taken during the helicopter fly-over:

Tokyo Electric releases new image of reactors

At 0:21 to 0:30 the reporter says, "TEPCO electric says a small silver light can be seen between the steel frames of the building in the video and is possibly the surface of the storage pool."

This video is shot from the south-east of Reactor 4 looking north-west. It the opposite side to that which we were discussing (north wall), although there is a very similar looking hole in the south wall.

You can draw your own conclusions about the "small silver light" being evidence that the SFP is full of water.
TCups
#400
Mar17-11, 08:30 PM
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Can someone give me a quick update on what has happened with the effort to establish a USA facility at Yucca Flats for the long term storage of high level radioactive wastes? Is the need for a safe facility to accept high level radioactive waste still as great as it was 25 years ago? Once upon a time, far, far away, I was the RSO of a hospital that had to "dispose" of some old cobalt sources. It was amazingly difficult then. I can only imagine what it must be like now. If there are lessons to be learned here, one is that storing high level radioactive wastes underground in salt formations that have been stable for millions of years is probably a better idea than storing them in pools along a coast line prone to quakes and tsunamis. Do I somehow remember that Harry Reid killed the Yucca Flats facility "NIMBY" style?
Texan99
#401
Mar17-11, 08:37 PM
P: 6
My impression -- and I'm hoping someone here can confirm if it's correct -- is that we tend to underestimate the sheer volume of water that needs to be pumped to keep all these reactors and pools cool enough. Someone on the WSJ comments section said they needed a megawatt of power and 4,000 volts, I think, to run the whole cooling system at full capacity. Firetrucks and water cannons may look like they're moving a lot of water, but it's just not enough. If that's so, then it may make a huge difference now that they've got adequate power supplies again.
Astronuc
#402
Mar17-11, 08:47 PM
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Quote Quote by TCups View Post
Can someone give me a quick update on what has happened with the effort to establish a USA facility at Yucca Flats for the long term storage of high level radioactive wastes? Is the need for a safe facility to accept high level radioactive waste still as great as it was 25 years ago? Once upon a time, far, far away, I was the RSO of a hospital that had to "dispose" of some old cobalt sources. It was amazingly difficult then. I can only imagine what it must be like now. If there are lessons to be learned here, one is that storing high level radioactive wastes underground in salt formations that have been stable for millions of years is probably a better idea than storing them in pools along a coast line prone to quakes and tsunamis. Do I somehow remember that Harry Reid killed the Yucca Flats facility "NIMBY" style?
Steven Chu put it on hold, ostensibly as a favor to Harry Reid for his support to Obama. The Yucca Mountain project, while technically sound, has been dogged by politics and the shifting winds (policy).
Astronuc
#403
Mar17-11, 08:58 PM
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Quote Quote by Texan99 View Post
My impression -- and I'm hoping someone here can confirm if it's correct -- is that we tend to underestimate the sheer volume of water that needs to be pumped to keep all these reactors and pools cool enough. Someone on the WSJ comments section said they needed a megawatt of power and 4,000 volts, I think, to run the whole cooling system at full capacity. Firetrucks and water cannons may look like they're moving a lot of water, but it's just not enough. If that's so, then it may make a huge difference now that they've got adequate power supplies again.
Unit 1 uses about 21 MWe for station services, and Units 2-5 use about 24 MWe. Assuming they need about 1% for cooling after shutdown, then they would need 210 kWe for Unit 1 and 240 kWe for Units 2, 3 and 4. However at this point the decay heat should be down to about 0.2%, they'd need about 50 kWe per unit for cooling. This is ball-park, back of the envelope since there are other station needs - so these represent the order of magnitude. The demands could be a few 100s of kWe.
turbo
#404
Mar17-11, 09:00 PM
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Quote Quote by Astronuc View Post
Steven Chu put it on hold, ostensibly as a favor to Harry Reid for his support to Obama. The Yucca Mountain project, while technically sound, has been dogged by politics and the shifting winds (policy).
Political expediency has made this into a zombie. There are SFPs all over the country (with various costs and labor needed to maintain them). What is wrong with going to a dry cask system and cleaning up all these pools? And making the US a harder target against terrorism, by the way. NIMBY can't be allowed to trump the common good, if we expect to advance. There are all kinds of people here in Maine that oppose the building of wind-power sites in the best places (mountain-ridges, peaks in high-wind areas) because "it wouldn't look nice".

I want to see humanity not only survive but advance and surpass us. Three or four generations from now, if wind power has turned out to be a dud, well the windmills could be torn down and scrapped without contaminating our water or air.
Astronuc
#405
Mar17-11, 09:09 PM
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Quote Quote by turbo-1 View Post
Political expediency has made this into a zombie. There are SFPs all over the country (with various costs and labor needed to maintain them). What is wrong with going to a dry cask system and cleaning up all these pools? And making the US a harder target against terrorism, by the way. NIMBY can't be allowed to trump the common good, if we expect to advance. There are all kinds of people here in Maine that oppose the building of wind-power sites in the best places (mountain-ridges, peaks in high-wind areas) because "it wouldn't look nice".

I want to see humanity not only survive but advance and surpass us. Three or four generations from now, if wind power has turned out to be a dud, well the windmills could be torn down and scrapped without contaminating our water or air.
Actually many utilities are going with dry storage and suing the US government to reclaim a portion of the $billions collected to pay for a storage facility - that may never operate. The government is reluctant to return the money, so the DOJ challenges the utilities on the expenses for the alternatives. It's kind of mind-boggling. If this program was done in the public sector, it would probably be illegal (as in RICO).
gmax137
#406
Mar17-11, 09:11 PM
P: 844
Quote Quote by uart View Post
Yes I know it's 20/20 hindsight, but this issue of site placement just seems like the biggest weakness in the whole design. Zero safety margin when compared to tsunamis from just the era of modern history. This surprises me since more elevation doesn't seem as if it would have been difficult problem.
Well let's say we pump the seawater to the condenser at 50 ft above sealevel instead of 5 feet (in otherwords, let's raise the elevation of the plant 45 feet). The pumping power for the 300,000 gpm circulating water flow rate increases from 380 to 3800 hp; at 60% efficient pumps that's an additional 4.2 MW load.

If they're selling the power at 50 $/MW-hr thats 212 $/hr or almost $2 million/year per unit or $12 Million per year at the 6 unit site.

That's payroll for over 100 employees for the whole site.

And that's why the plants are built close to sea level.


Obviously in hindsight it would be done differently, but still you see the rationale. Someone upthread was critisizing 'Ebesco' for the design; first, it's 'EBASCO', a big US engineering company, second, nobody hires engineers who want to throw away $12 million a year.
AntonL
#407
Mar17-11, 09:14 PM
P: 521
Quote Quote by Texan99 View Post
My impression -- and I'm hoping someone here can confirm if it's correct -- is that we tend to underestimate the sheer volume of water that needs to be pumped to keep all these reactors and pools cool enough. Someone on the WSJ comments section said they needed a megawatt of power and 4,000 volts, I think, to run the whole cooling system at full capacity. Firetrucks and water cannons may look like they're moving a lot of water, but it's just not enough. If that's so, then it may make a huge difference now that they've got adequate power supplies again.
According to NY times diagram the volume is 39200 cubic feet or 1110Tonnes of water and each storing about 550 tonnes of fuel; - this is per reactor and there is a seventh storage pool containing 6000 tonnes of spent fuel the seventh pool is 29x12 metres and 11 metres deep

Edit: Sorry, its not 6000 tonnes of spent fuel as of March 2010 is was 1760Tonnes
Attached Files
File Type: pdf Containment Pools.pdf (1.85 MB, 23 views)
turbo
#408
Mar17-11, 09:23 PM
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Quote Quote by Astronuc View Post
Actually many utilities are going with dry storage and suing the US government to reclaim a portion of the $billions collected to pay for a storage facility - that may never operate. The government is reluctant to return the money, so the DOJ challenges the utilities on the expenses for the alternatives. It's kind of mind-boggling. If this program was done in the public sector, it would probably be illegal (as in RICO).
I hear you. When I started investigating the costs of dry casks, I was flabbergasted. How can a utility safely contain, transport, and safely store the nuclear wastes that they produced with costs like that? There has to be a way to clean out these depots full of spent fuel, and consolidate that storage in a secure facility.

It can be (and probably should be) argued that many power companies took advantage of government subsidies to get into nuclear power, and reaped 30-40 years of fat profits as a result. Now, should we be able to claw back some of those profits, or should we expect the US taxpayer to cough up and pay to evaluate, consolidate, transport and store those waste products to make us safer?

I'm verklempt - talk among yourselves.
AtomicWombat
#409
Mar17-11, 10:29 PM
P: 150
Quote Quote by AntonL View Post
According to NY times diagram the volume is 39200 cubic feet or 1110Tonnes of water and each storing about 550 tonnes of fuel; - this is per reactor and there is a seventh storage pool containing 6000 tonnes of spent fuel the seventh pool is 29x12 metres and 11 metres deep

Another estimate of the quantity of fuel at each site is here:

Fuel Amounts at Fukushima



"While BWR fuel comes in various sizes, the last column assumes 170 kg per assembly. Each fuel assembly consists of roughly 60 fuel rods."
Reno Deano
#410
Mar17-11, 11:35 PM
P: 128
Now we know why TEPCO is so focused on keeping the fuel pool at Unit 3 filled with water, MOX fuel in the pool. I also see that the news agencies have picked up on the MOX fuel at unit 3.

They are infor some interesting questioning from the public about keeping that quiet....but I don't blame them.
Reno Deano
#411
Mar17-11, 11:41 PM
P: 128
The link below is the Safety Evaluation report for testing the use of MOX fuel at a US PWR plant for two fuel cycles. Very detailed on fuel pellet design and increase in GAP release concentrations.

http://adamswebsearch2.nrc.gov/idmws...5&id=040970215
AtomicWombat
#412
Mar17-11, 11:49 PM
P: 150
Quote Quote by AtomicWombat View Post
Here is an English language version of the video taken during the helicopter fly-over:

Tokyo Electric releases new image of reactors
Can someone get a screen grab (still picture) from this video please. I don't know how. At about 0:16 it shows the north wall of building 4 where I earlier suggested there was evidence of coria (molten fuel rod assemblies). Others suggested it was insulation. Well the insulation appears to have 1) crept further down the wall and onto a the emergency vent pipe; and 2) changed colour to a much darker shade (although colour reproduction is poor).

Another link:

http://www3.nhk.or.jp/daily/english/...18_02_512k.asx
tyroman
#413
Mar18-11, 12:30 AM
P: 138
Quote from Astronuc's post #338:
"I don't believe 5 and 6 were as badly damaged, and their EDGs may actually be working. Unit 6 has Mk II containment, but Unit 5 is Mk I and similar to Unit 4.

Units 5 and 6 may have been shutdown earlier - which means cooler fuel, or perhaps they reloaded the cores, so the spent fuel pool does not have the burden of the reinsert fuel."

Possible explanation is here - see the portion I have set off in brackets [ ]:
From:
Information about the incident at the Fukushima Nuclear Plants in Japan hosted by http://web.mit.edu/nse/ :: Maintained by the students of the Department of Nuclear Science and Engineering at MIT
See:
http://mitnse.com/
Under:
News Updates and Current Status of Facilities
Posted on March 16, 2011 10:59 am UTC by mitnse

"Units 4-6: Flames at Unit 4 were reported to be the result of a pump fire, which caused a small explosion that damaged the roof of Unit 4 (See TEPCO’s press release on the most recent fire at http://www.tepco.co.jp/en/press/corp...1031606-e.html) . Efforts at Units 4-6 are focused on supplying cooling water to the spent fuel storage pools. Temperatures in these pools began to rise in the days after the quake.

[At the time of the quake, only Unit 4’s core had been fully offloaded to the spent fuel pool for maintenance; roughly 1/3 of the cores of Units 5 and 6 had been offloaded. This explains in part why the temperature in Unit 4’s pool has risen faster than at the other reactors: it has a higher inventory, both in fuel volume and in heat load.]

Outlook: The fuel within these pools needs to remain covered with cooling water in order to prevent the low levels of decay heat present from causing it to melt, and also in order to provide shielding. Boiling of the water results in reduction of the water level in the pools, so if/when the pools get hot enough for boiling to begin, water needs to be added to replace what boils off. The staff of Unit 4 plan to begin pumping water to the spent fuel pool from ground level as soon as radiation levels from Unit 3 are low enough for them to return. This pumping operation should be relatively easier than injection of cooling water into the reactor vessels at Units 1-3 because the pools are at atmospheric pressure."

The Status/Outlook approach they use is nice. Unfortunately, they did not source the info I have bracketed.

.
AntonL
#414
Mar18-11, 01:23 AM
P: 521
This is a bit off topic but relevant - anybody recognize this Nuke Plant?


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