Japan's Nukes Following Earthquake

[SloGlo]

I dont see the 1-7 scale in there, seems to be a risk assesment vs actual scales.

it wood appear that if yew melt yore core 'n set fire two your moderator to send said core all over the countryside, you are hi on the scale.  if you melt your core 'n keep your containment intact to maintain control of your contamination you are low on the scale.  iIf you are in between those too, you are middle of the scale.

[tr]

Site with some IR pictures of the 4 reactor buildings.  Unit 2 doesn't look so good.

http://bigdustup.blogspot.com/2011/03/infrared-ir-thermal-images-of-fukushima.html

[OldHP]

Following this incidnet makes me realize the major media has ADHD.
Just last week this was the unending focus of the media.  Nothing but non-stop breathless reporting about how dire the situation was.
This week?  Nothing, it is forgotten.

Did you mean incident?

And did you happen to notice that we (the US) entered into military action in Lybia with major action from the Naval and Air Forces?  What means more to the media?

[Cycoticpenguin]

it wood appear that if yew melt yore core 'n set fire two your moderator to send said core all over the countryside, you are hi on the scale.  if you melt your core 'n keep your containment intact to maintain control of your contamination you are low on the scale.  iIf you are in between those too, you are middle of the scale.

Im in between really annoyed and really amused, so I will remain nuetral to this comment

[RRhoads]

Im in between really annoyed and really amused, so I will remain nuetral to this comment

Hey Yngwie..dont get mad or frustrated..
Try this link.

http://www.google.com/

[Marlin]

This explains a lot and fills in a couple of holes for me.

In the U.S., only the most worn-out rods typically are removed and transferred to a spent-fuel pool for storage, where they can stay for decades. Thus, U.S., pools hold only the oldest spent fuel, which is also the coolest in terms of temperature and radiation.

By contrast, at Tepco and other utilities, it's common to temporarily remove all the fuel rods. The freshest are eventually moved back to the reactor pressure vessel and supplemented with new rods to replace the oldest ones, which are left in the storage pools.

http://online.wsj.com/article/SB10001424052748704433904576212980463881792.html

[Roll Tide]

This explains a lot and fills in a couple of holes for me.

In the U.S., only the most worn-out rods typically are removed and transferred to a spent-fuel pool for storage, where they can stay for decades. Thus, U.S., pools hold only the oldest spent fuel, which is also the coolest in terms of temperature and radiation.

The only units I have seen perform an inside the core shuffle  (instead of full-core offloads) are the places without enough room in the SFP to fully off-load the core. I have heard of PWR's that think they could reload faster this way....

Since Unit 4 was shutdown for 5 months, I don't think they were trying to set a record outage....

[hamsamich]

Full core offloads are all I remember, but I wasn't always on the refuel floor....

[Marlin]

All I remember are incore shuffles but then many plants had not gone to high density racks and many of the older plants were out of room. A lot of reracks were done in the 80s to accomodate full pools.



Note: I have not been in a power plant since the early 90's.

[navynukedoc]

This was posted on this thread five pages and six days ago,....

http://resources.nei.org/documents/japan/Used_Fuel_Pools_Key_Facts_March_16_Update.pdf

it's a good read,....

good stuff for us guys who have never been inside one of those! Thanks and Karma on this one!

[roadhp]

BWR's can do the shuffle thing because their fuel is self supporting, unlike PWR's that are just held in by the bottom latches and each other.  Most PWR's do a full core offload to take water level below the flange for S/G eddy current to set the nozzle dams.  BWR's don't have that problem, and with the smaller and therefore more numerous bundles, and the fact that they don't have to worry about an upender and transfer tube, a reshuffle just makes sense.

[Marlin]

This was posted on this thread five pages and six days ago,....

http://resources.nei.org/documents/japan/Used_Fuel_Pools_Key_Facts_March_16_Update.pdf

it's a good read,....

I read it but it does not mention a 100% off load of fuel during the maintenace cycle.

[Touche]

I read it but it does not mention a 100% off load of fuel during the maintenace cycle.

An earlier post by peachie stated the following from a WANO Update (is the update accurate...*shrugs*)

"Miscellaneous Information—The number of spent fuel assemblies in the spent fuel
pool of each unit is as follows:
Unit : number / capacity
Unit 1: 292 / 900
Unit 2: 587 / 1240
Unit 3: 514 / 1220
Unit 4: 1331(*) / 1590
Unit 5: 946 / 1590
Unit 6: 876 / 1770
Common (Shared) fuel pool: 6375 / 6840
(*) 1331 includes 783 spent fuel assemblies and 548 unloaded from the reactor for the inspection."

This would seem to make sense for Unit 4 if it was preparing for, or performing, in-core inspections...if I recall correctly, there use to be a 10 year in-core ISI inspection that required a complete fuel offload...heck, one inspection resulted in a diver going into the vessel and I know we did a full core offload for that.

I am not a planner, but I would think the scheduled maintenance and plant capabilities would dictate either full off-load or in-core shuffle.

[Marlin]

I am not a planner, but I would think the scheduled maintenance and plant capabilities would dictate either full off-load or in-core shuffle.

   Understood, the article I cited states that these plants do it as a routine each cycle which is not normal for an American BWR putting a much larger heat source from decay heat in the spent fuel pool on a routine basis. This was cited in the WSJ article as one of the contributing factors for the unexpected heating and fires in the spent fuel pool. I get and got that there is a distribution of fuel bundles in different states of decay between the reactor, the spent fuel pool, and the dry fuel cells. The article states that the ratio of recently removed bundles in the spent fuel pool is higher than might be expected in an American reactor in a normal fuel cycle.

[Touche]

   Understood, the article I cited states that these plants do it as a routine each cycle which is not normal for an American BWR putting a much larger heat source from decay heat in the spent fuel pool on a routine basis. This was cited in the WSJ article as one of the contributing factors for the unexpected heating and fires in the spent fuel pool. I get and got that there is a distribution of fuel bundles in different states of decay between the reactor, the spent fuel pool, and the dry fuel cells. The article states that the ratio of recently removed bundles in the spent fuel pool is higher than might be expected in an American reactor in a normal fuel cycle.

Agreed 

Something I forgot to ask (I was in a hurry to leave for home)...What is the typical number of fuel bundles in this type of reactor? Does 548 account for a full offload?

[roadhp]

It really doesn't matter for a BWR unless the weir gate is closed since the fuel pool and the cavity are connected.  The only difference would be the close packing in the reactor side verses the larger spacing and therefore better heat transfer capacity in the fuel pool.

[playswithairplanes]

According to several reports, the Tokyo Water Supply has reported I-131 contamination in the tap water at 210bq/L. Which is 5676 uuCi/L. Report says it's twice the limit for infants.

[eldeelf]

http://www.aolnews.com/2011/03/22/chernobyl-cleanup-survivors-message-for-japan-run-away-as-qui/

I found this article yesterday and was up last night thinking of all the things wrong with this. Just wanted to post this so others would see the bad information be put out by the media. This lady did a great thing but now has decided to turn it into something bad. I just hope others see the truth as I did. We really don't need this adding to the fears people already have about Nuclear Power.

[navynukedoc]

http://www.aolnews.com/2011/03/22/chernobyl-cleanup-survivors-message-for-japan-run-away-as-qui/

Good point. Something I keyed in on was the "Chernobyl Necklace". Thyroid issues are common even in people who have never been to Russia. Way to go to scare people even more.

[eldeelf]

I know I am outraged by this article and the comments made by people. I wish someone would just state the facts for once. You are so right about the Thyroid issues. I wish there was better reporting on the issues and not opinions.

[IRLFAN]

Good point. Something I keyed in on was the "Chernobyl Necklace". Thyroid issues are common even in people who have never been to Russia. Way to go to scare people even more.

I've never been to Chernobyl, and I had half of my thyroid removed 7 years ago.  Thyroid problems are also genetic, my maternal grandmother died from a thyroid tumor.  Back then there were no thyroid hormone replacements.

[namlive]

Konnichawa,
I have been reading the IAEA reports which seems to have the best information. I have been busting my hump on unit conversions. This is what I have been able to make of the situation in numbers we understand. Contamination levels up to 40 miles from the plant has reached levels of 150K on a 1 meter LAS or 15K dpm/100 cm2 beta-gamma, most of which is I-131. No alpha has been detected. This gives a general area dose rate of .9 mr/hr. At one point at about 20 miles from the plant, the dose rate (I assume from the plume since the numbers were smaller closer to the plant) were as high as 17 mrem/hr.
The gatehouse reached a maximum of 1,200 mrem/hr, this was 28 mr/hr as of yesterday. This maximum was when they had a high dose area of 40 rem/hr between units 3 and 4 with unconfirmed readings as high as 100 R/hr. Their dose limit was 10 REM and turn back number was 1 Rem/hr. When they exceeded that in the control room, they upped the limit to 25 rem and 10 rem/hr. So far of the "50" workers, 17 have received exposures greater than 10 REM.
There is a possible Chernobyl scenario as unit 4 SFP is covered with nearly 90 tons (I have a hard time with that number) of sea salt which is acting as an insulator for the spent fuel. This does not allow cooling while at the same time allows hydrogen to build up. If unit 4 SFP has even a slight hydrogen explosion, this could be an accident where lives are lost due to radiation with 1331 spent fuel bundles in the pool with the most recent defueling of the reactor Nov. 2010. I want to publically thank a person we all know as "Bruce" for my level 1 Japanese Rosetta Stone.
I apologize if this is a repeat of information. I didn't read all 20 pages.

[matthew.b]

Sea water is 3.5% solids.  To get 90 tons of salt would require the evaporation of 2500 tons of seawater.  To evaporate that much water in 15 days would require about 6500 MW average power so I don't buy the 90 tons of salt claim.

I could buy that 90 tons of seawater - that could happen with 200MW of average power.

I wonder what their efforts to get freshwater to the plant are?   

[Nuclear Renaissance]

Can a member explain why a plutonium MOX fuel poses a greater danger in a breach situation than regular low-enriched uranium fuel? Is it appreciable?

[navynukedoc]

I wonder what their efforts to get freshwater to the plant are?   

"Tokyo Electric Power Co. is stepping up efforts to switch from sea water to fresh water for cooling the reactors and used fuel storage pools. The United States government has urged the switch to fresh water as soon as possible and is providing two U.S. Navy barges, each of which can carry up to 1,000 tons of water. The ships are scheduled to reach port about 60 kilometers from the Daiichi plant in about three days. Japanese workers at the site will install pipes and hoses to carry the water to the plant."

from source http://nei.cachefly.net/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region/