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Japan nuclear power stations

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Japan nuclear power stations

Old 16th Mar 2011, 10:45
  #201 (permalink)  
 
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dead_pan
Quote: A BWR fuel assembly comprises 90-100 fuel rods, and there are up to 750 assemblies in a reactor core, holding up to 140 tonnes of uranium.
Source: Nuclear Reactors | Nuclear Power Plant | Nuclear Reactor Technology

I could not find anything specific for the Fukushima facility. (I'm guessing the above description is typical).
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Old 16th Mar 2011, 10:49
  #202 (permalink)  

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Bit of a wind up going on over at R+N

London VAAC has issued at 0300 UTC a
NUCLEAR EMERGENCY
DTG: 20110315/0300UTC
ORIGIN: VAAC LONDON
INFO SOURCE: IAEA
STATUS: EMERGENCY
SITE: FUKUSHIMA
LOCATION: N0037E0141
START OF RELEASE: 20110315/0300 UTC
END OF RELEASE: ONGOING
FIR NAMES: FUKUOKA, MANILA, TAIBEI, SHANGHAI, INCHEON,
PYONGYANG, VLADIVOSTOK, KHABAROVSK, YUZHNO-SAKHALINSK, ANCHORAGE.
FIR CODES: RPHIZRZX, RCAAZQZX, ZSSSYMYX, RKRRZQZX,
UHWWZRZX, UHHHZRZX, UHSSZRZX, PAZAZQZX
I repeat, wind up !!
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Old 16th Mar 2011, 11:41
  #203 (permalink)  
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Three Mile Island - no deaths ?

The Radiation and Public Health Project cited calculations by Joseph Mangano, who has authored 19 medical journal articles and a book on Low Level Radiation and Immune Disease, that reported a spike in infant mortality in the downwind communities two years after the accident

You reads what you wants. and takes your choice of what you believes.....
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Old 16th Mar 2011, 11:46
  #204 (permalink)  
 
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El Grifo,

How about going to read it yourself on CFMU before declaring it a wind up !
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Old 16th Mar 2011, 12:11
  #205 (permalink)  

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Source ------------

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Old 16th Mar 2011, 12:12
  #206 (permalink)  
 
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Yes, and same "source" would also reveal the following post by "opsjocky"

Same message on CFMU / Network Operations Portal (NOP) website...

To which I replied :

opsjockey,

So it is. Including the footer saying :

Pls note that the above message is not published in VAAC website.


As well as a followup post by OutsideCAS with whom I wholehartedly agree....

Always amazed at some comments made - even if the areas highlighted are perhaps a little over the top by way of restriction, is this not far better than risking flying through an area and frying your testicles (or not in the case of females) in radioactive matter ??



Seriousy El Grifo. Show more respect for the professionals behind the release of such warnings. Afterall, as aviation professionals, we expect people to show respect for our profession.
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Old 16th Mar 2011, 12:13
  #207 (permalink)  
 
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OFSO

There has never been a death DIRECTLY attributed to Three-Mile Island.

And, let's get some figures out here, the rate of infant mortality (remember, this is children up to 1 year old) from cancers downwind of TMI went from 0.85 per thousand in 1979-1983 to 1.17 per thousand in 1984-1988. That means that the infant mortality rate from cancers in the 4 years after TMI was LOWER than the US national average and rose to above the average after that period.

These figures alone speak volumes..........
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Old 16th Mar 2011, 12:26
  #208 (permalink)  
 
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Regardless if it yet another spoof or not, there is a serious point here re perspective. Pilots and crew are exposed to considerably higher levels of background cosmic radiation as a consequence of their job - Google it and see. A brief inadvertent jaunt through a radioactive plume will not even register by comparison. Yet another over-reaction.

BTW wasn't there a no-fly zone around the area anyway? Gosh, a no-fly zone we can all agree on for a change.
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Old 16th Mar 2011, 12:37
  #209 (permalink)  

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So is it real or is it a "spoof". That is the question !
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Old 16th Mar 2011, 12:46
  #210 (permalink)  
 
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Cool

Hi,

A look at the homepage of the site that your link is from speaks volumes about the credibility of anything on that site..........
In this case the home page is not of importance.
The important is the contain of the articles and the sources ...
They are just the messengers.
Never kill the messenger !
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Old 16th Mar 2011, 12:55
  #211 (permalink)  
 
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And, let's get some figures out here, the rate of infant mortality (remember, this is children up to 1 year old) from cancers downwind of TMI went from 0.85 per thousand in 1979-1983 to 1.17 per thousand in 1984-1988
So the question is what where the total amount of babies in the sample and what was the uncertinity on it. The figures look too low to gain any statistical signifigance from them.
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Old 16th Mar 2011, 13:01
  #212 (permalink)  
 
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So the question is what where the total amount of babies in the sample and what was the uncertinity on it. The figures look too low to gain any statistical signifigance from them.
That study looked at every infant mortality and it's cause in 34 counties downwind of TMI. It wasn't just a "sample".
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Old 16th Mar 2011, 13:40
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Have just seen some close-up piccies of the facility on Sky. Unit 1 seems unchanged from Sunday, and the external fabric of Unit 2 looks comparatively undamaged. Unit 4 look almost as damaged externally as Unit 3 - assuming this was caused by the explosion and/or fire yesterday? That said, the roof of Unit 4 looked to be more-or-less intact, although covered with debris. Maybe this is in-part why they pulled the heli op, as it seems unlikely they would be able to drop water through the roof into the spent fuel pond. I also wondered whether they weren't prepared to sacrifice any heavy-lift heli capability just yet, given they are crying out for this elsewhere in the country? The Chinooks could get heavily contaminated in such an op.
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Old 16th Mar 2011, 14:12
  #214 (permalink)  
 
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As no-one has answered my questions in post #27 (page 2 of this present thread), I googled.
Here is the result of my search :

- What would be the temperature of the core IF it begins melting ?(I really, really hope it won't)
When a nuclear core is not cooled at all, temperature increases at a rate of 0.6C per second (+/-0.3).
Specific temperatures :
1100C : Zircaloy containers of Uranium rods are damaged.
1500C : Zyrcaloy reacts with steam. Rapid oxydation of Zircaloy creates heat and Hydrogene.
1700C : Bore control bars melt, fall at the bottom of steel container and freeze (relatively cold at the bottom)
2150c : Zyrcaloy melts and freezes at the botom of the container together with Uranium-dioxide pellets.
2800C : Uranium-dioxide melts

This is called "corium relocation". As Uranium and Bore don't weight the same, neutrons are not stopped anymore. Reaction continues until cooled and/or bore is aded.

Core can reach 3200C.

- What is the melting temperature of the stainless steel container ?
I haven't found actual melting point.
I just found that only Tungsten would melt above 3200C (melting point 3400C) but Tungsten is too soft to resist high pressures. So it has to be mixed with other stuff which reduce the melting point in order to increase the breaking point.
Apparently, in Three Mile Island incident, the partial melting of the core and subsequent freezing of debris at the bottom of the container protected said container from melting (which was not expected)

- Is this temperature the same once the sea water has corroded everything ?
In fact, the problem is more mecanical constraints than salt in the water. Heating from inside and cooling from outside may change the resistance level of the steel container.
If ever the container breaks and the hot core (3000C) falls in high-pressure, liquid phase water, this could end up in a steam explosion, also called "littoral explosion" because that's the same result as lava reaching coast during an irruption.

- How does concrete react to high temperatures ?
Concrete doesn't melt.
The metallic reinforcement inside would melt around 1500-1800C.
Concrete itself looses its properties around 2500C. Chemical reactions occur and it's resistance becomes comparable to sugar cubes.
Between 2500 and 2800C, concrete becomes sand and sand melts at 2800C

- How long would the core take to cool down ?
The core will need several days to cool down, once cooling will be possible.

- What will be the SOP to clean the place afterwards ? Is there a SOP ?
I haven't found SOP to dismantle a nuclear plant.
From the informations I've found, it takes 30 years and costs around 100,000.00 per MW.


I would be interrested in being corrected if I'm wrong.

Last edited by BrATCO; 17th Mar 2011 at 19:21. Reason: Uranium-dioxide melting point
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Old 16th Mar 2011, 14:38
  #215 (permalink)  
 
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Interesting data. I understand that zirconium will catch fire if exposed to air.

Also, spent fuel is not in any containment as per that in the reactor core - its stored in flasks under water. According to one expert yesterday this water would relatively quickly begin to boil if left uncooled. It would take several days unattended for it to boil down to such a level that the spent fuel itself was in danger of melting.

Apparently the o/h crane used to load and unload the spent fuel in Unit 4 has 'gone away', so no chance of unloading it and moving it elsewhere in the immediate future.
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Old 16th Mar 2011, 14:47
  #216 (permalink)  
 
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BrATCO Interesting data .

Not sure where you got the decommissioning costs as a factor of power output . OK the bigger they are the more it costs but design is a significant factor .
However the big issue here is damage which will add massively to the costs . You cant just lift the fuel pins as they do when refueling special kit will have to be designed and built .
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Old 16th Mar 2011, 14:48
  #217 (permalink)  
 
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I haven't found SOP to dismantle a nuclear plant.
From the informations I've found, it takes 30 years and costs around 100,000.00 per MW.
I wouldn't expect an SOP for the cleanup of an event like TMI or Fukushima, there ain't exactly been a lot of these things happening and I would expect every one would be different so you couldn't have an SOP although the practices and methods used would be fairly "standard" worldwide.

As far as the time and costs goes, TMI gives us a perfect example, although you would have to figure out what the costs back then are now.

The cleanup of the damaged nuclear reactor system at TMI-2 took nearly 12 years and cost approximately US$973 million. The cleanup was uniquely challenging technically and radiologically. Plant surfaces had to be decontaminated. Water used and stored during the cleanup had to be processed. And about 100 tonnes of damaged uranium fuel had to be removed from the reactor vessel -- all without hazard to cleanup workers or the public.
Obviously things would change now as methods used then may well have been "refined" and the use of "robots", etc, would change the methods used, but I guess it will give us a very rough figure.
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Old 16th Mar 2011, 15:31
  #218 (permalink)  
 
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HuntandFish,
Not sure where you got the decommissioning costs as a factor of power output .
Sorry, it took me two days to gather these informations, I didn't keep the links, just tried to keep the "believable" sources and get a general idea.

I seem to remember these costs are for normally stopped nuclear plants and that's an average I made, based (among other sources) on reserve founds EDF and UK nuclear company are supposed to keep to dismantle their plants.
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Old 16th Mar 2011, 15:45
  #219 (permalink)  
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For those interested:

Nuclear decommissioning - Wikipedia, the free encyclopedia

Zion Nuclear plant in the US (Illinois) (it's a PWR) is in the process of being de-commissioned. So far i'ts been years. It was a safe shut down so the process is a lot different than the one that will have to take place in Japan.
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Old 16th Mar 2011, 15:50
  #220 (permalink)  
 
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That was why I used TMI as a comparison regarding the cleanup operation, Chernobyl was obviously never "cleaned up", and over a decade to clean up the site would be a good estimate based on what has happened so far (in fact, it would be longer since there are more reactors involved, best make that 2 decades)
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