Spent Fuel Pools

[RobertEarl]

Imagine a huge pool supported in the air, the bottom of the pool 50 feet off the ground. And in that pool are stored spent fuel rods from a nuclear reactor. There are many tons of material sitting in that pool. The reason these rods are in that pool is to keep the rods from releasing their heat to the atmosphere.

If the rods were not in water the reaction with the atmosphere would cause fire and explosions. The simple fact is: water puts out fires.

In these pools the water is supposed to circulate. Rod heated water is run through heat exchangers and cooled down and pumped back into the pools.

What happened at Fukushima is that the pipes circulating the water broke due to the earthquake. Also the backup electricity failed and the pumps stopped working. Too, the pumps were inundated by water from the tsunami.

All in all a complete failure. What we do know is that the same systems which keep pools from overheating also failed when it came to the cores and three cores full of these hot-rods have melted down.

What we don't know is the past conditions of the 4 spent fuel pools. There is speculation that the spent fuel pools did lose water like the cores did, did overheat, and did release radiation to the atmosphere.

The big fear now is that the pools of the four reactors may fall to the ground dumping the rods all over the place.

If they could just pick the rods out of the pools with a crane and place them in a pool on the ground, they would, but they can't. That is why the rods are still in the pools 50 feet off the ground, just hanging there.

[madokie]

1. Even with this catastrophe there is those who advocate for building more of the same

Stupid is as stupid does

[RobertEarl]

2. Yep. Hard to believe

Japan sure learned their lesson. Not only will another nuke plant not be built in Japan, they are going to close down 50 plants and be nuke free.

Nuke free that is, once all the spent fuel rods are put away safely.

But that may take a few centuries. In a human timeline, that is forever.

[FBaggins]

3. The first word of your post is the critical one to understanding it.

"Imagine".

reason these rods are in that pool is to keep the rods from releasing their heat to the atmosphere.

Really? So it's a global warming thing... not a concern about radiation?

In these pools the water is supposed to circulate. Heated water is run through heat exchangers and cooled down and pumped back into the pools.

Interesting. And given that warm water is less dense than cold water and you want to remove the heat... where is the intake for that system?

Now what happened at Fukushima

Please provide a link to something other than "imagine". Those pipes (SFP 4 as an example) were still destroyed three months later... yet the pool held water.

[RobertEarl]

4. Right. As I said:

"What we don't know is the past conditions of the 4 spent fuel pools. There is speculation that the spent fuel pools did lose water like the cores did, did overheat, and did release radiation to the atmosphere."

As of now, they do seem to have fixed the pipes, repaired the pumps and electricity restored. Now the problem is that the pools could fall to the ground.

[FBaggins]

5. Please refer to the following if you want a laugh.

Note the piping arrangement? Note the "Anti-Siphon Mechanism"?



As of now, they do seem to have fixed the pipes

But they didn't fix them for months after the explosions. How did they hold water given your imagination?

Now the problem is that the pools could fall to the ground.

Aaaand... we're right back to "imagine".

There's only one thing that fails to hold water here RE... your argument. You made up a fictional scenario and you didn't know what you were talking about. It's time to admit your error.

[RobertEarl]

6. They did not 'hold water'

The pools lost water is the studied reasoning.

We know circulation stopped. When that happened the water heated up and evaporated. Leaving the tops of the rods exposed. Really, this is all such simple physics.

As to the drawing posted. One, not all the piping and valves (anti-siphon included) worked after the earthquake. Then there were explosions, cranes falling, etc.

And look closely at the diagram. See the gates into the reactor? What happened if the gates cracked open? Yup, the water drains away.

What if a valve in the bottom of the pool broke? How about a crack in the concrete after EQ and explosions, crane fall etc.

Surely you are not gonna say you somehow know the pools stayed slap full through all the calamity. No one would be that dumb. So what is it you are trying to say?

Or is this my real error? Imagining you are claiming the pools never lost water? The cores lost water, but the pools did not?

I report, you decide. Did the pools stay full, or not?

[FBaggins]

7. You're seriously sticking with that?

You're immune to correction, eh?

The pools lost water is the studied reasoning.

Whose "studied reasoning"? And, more to the point, who among them said that they "lost water" because it leaked out of damaged pipes? Much of it is thought to have boiled off... not leaked out. And that couldn't have caused the hydrogen explosions.

We know circulation stopped. When that happened the water heated up and evaporated. Leaving the tops of the rods exposed. Really, this is all such simple physics.

Lol! Yep... it's also a complete change in your story. Thought anyone would miss that?

As to the drawing posted. One, not all the piping and valves (anti-siphon included) worked after the earthquake. Then there were explosions, cranes falling, etc.


How do you imagine that that's relevant? Nothing changes the fact that you thought of those pools as bathtubs with drain holes in the bottom that leaked out the water when the pipes were damaged. That simply wasn't true.

And look closely at the diagram. See the gates into the reactor? What happened if the gates cracked open? Yup, the water drains away.

Yep... and the bottom of those gates is above the tops of the fuel rods... so it couldn't drain below that level. More importantly... there's no possibility that those gates have been repaired... so the fact that the pools are well above that level proves that it didn't happen.

What if a valve in the bottom of the pool broke?

How can a non-existent item break?

How about a crack in the concrete after EQ and explosions, crane fall etc.

There were quite a few of us who worried about that possibility at the time... but nobody can get to such leaks to fix them... so once again, the fact that the pools are currently full already answers the question.

Surely you are not gonna say you somehow know the pools stayed slap full through all the calamity

Of course not. The point was simply that you didn't know what you were talking about. You presented a claim of exploding fuel which never happend.

[RobertEarl]

8. There ya go

FBaggins writes:"Much of it is thought to have boiled off... not leaked out" Re: out of the spent fuel pools.

Yes, boiled off. The pools overheated and boiled off the water. Then when the water level went below the tops of the rods the rods reacted with the air and began burning. Releasing radiation.

Remember the small crane they had outside the fuel pool spraying water on the pool to fill the pool back up to cover the rods? That proves your point that the pools overheated and boiled off the water. It was so bad they had to bring in that pump.

[FBaggins]

9. Well... you're getting closer.

So I suppose the teasing can stop.

Yes, boiled off. The pools overheated and boiled off the water.

Close. The way you worded it implies that they boiled dry (or almost). There was fear that this could happen (a year ago), but it doesn't appear that it did.

Then when the water level went below the tops of the rods the rods reacted with the air and began burning. Releasing radiation.

Two errors there. This is at least the second time that your statement implies that you think there is a reaction between the fuel and the air. That isn't the case. The water provides both cooling and shielding, but the lack of water does not change the rate of decay heat not the activity level in the fuel.


Remember the small crane

Actually, IIRC it was one of the three largest concrete pumping trucks in the world.


Regardless... here's the crux of the conversation. The fuel pools were certainly a priority and a great risk at the time, but they were not the source of the explosions. Uncovering the tops of the fuel would be very dangerous to anyone standing above the pool, but would not have much of an impact otherwise. Your'e forgetting another basic physics principle. It's hard to heat just one end of a metal rod when the other end is still being cooled. In order for the fuel to burst into flames they first had to raise the temperature of the pool to boiling and then boil off substantially all of the water.... THEN they could get hot enough to burn.

The problem is that there are physical constants involved here. Even in the pool with the highest level of activity (#4), it would take a week or more to heat it up enough and boil off the water (and as you note, they were adding water). The explosions took place long before that point.

[RobertEarl]

10. wow

There has been some discussion about where the explosions came from....

I see you think the fuel pools are intact and never exploded, even tho you do say the water boiled off. Hmmm

The only other items which could explode were the cores in the reactors. Thus you claim the reactor cores did indeed explode.

You do know there are people who don't believe much of what you claim, and I can see why. Think of this as a chance to clear your name by telling us your theory of what happened at each of the four reactors.

Don't consider it a challenge.... just think of it as imparting all your wisdom.

[FBaggins]

11. Ow well... back to the irrational.

And you were making such progress!

I see you think the fuel pools are intact and never exploded,

So does pretty much everyone else. The videos from inside the pools showing them intact and unexploded certainly help.

even tho you do say the water boiled off. Hmmm

And I guess I have to correct this error once again? I didn't say that ALL of the water boiled off... and you're incorrect to assume that fuel explodes when it hits the air. Repeating the ridiculous doesn't make it any more credible.

The only other items which could explode were the cores in the reactors. Thus you claim the reactor cores did indeed explode.

What on earth gave you that notion? That's the "only other items which could explode"? The cores didn't explode... they melted down, giving off hydrogen that had to be vented from containment. The vented hydrogen collected within the outer building shell (including some that vented from unit 3 over to unit 4) and eventually exploded. This isn't a made up theory as the half dozen or so you've invented this week... it's the consensus of pretty much every expert involved and has been for well over a year. Where have you been?

Prior to the first explosion it was a known and reported danger. It was one of the fears at Three Mile Island. This isn't news.

[RobertEarl]

12. 4 cores 4 different scores

Each of the 4 reactor buildings have been altered in different ways.

1... Melted core and hydrogen explosion. The video shows a clear cloud rising from the explosion. Building not destroyed.

2... Melted core and possible fuel pool boil over and continued steam escapes. Building not destroyed.

3... Huge explosion with dark colors in the clouds leading one to believe that the actual core itself exploded. Building destroyed. Too dangerous for humans to approach.

4... Core was empty. Fuel pool contained fresh spent fuel and building melted because of fires and excess heat.

Plutonium from core #3 has been found spread around the world.

[PamW]

13. CORRECTION!!!

3... Huge explosion with dark colors in the clouds leading one to believe that the actual core itself exploded.
========

Leading those who don't know the science to conclude that the actual core itself exploded.

Unit 3 suffered the same fate as Unit 1; a hydrogen explosion. However, Unit 3 had more time to accumulate more hydrogen before an explosion was triggered.

Reactor cores can't explode - that is they can't have the type of nuclear explosion one sees in a bomb. The fuel is too dilute; only 3-4% fissile material. Even in MOX, the percentage of plutonium is about 7%. One can not use a mixture that is <20% U-235 or <15% Pu-239 for bomb fuel. It's physically impossible to have such mixtures used for bomb fuel. In fact, the legal requirements for security change at the above levels so that less security is needed for material that can not be used to make a bomb.

Before the anti-nukes barrage with their misconceptions; mushroom clouds can happen with any explosion, not just nuclear. The fireball of the Unit 3 explosion was yellow, which meant it was not hot enough to emit greens, blues, and violets. Nuclear explosions emit frequencies all the way up to X-rays. Hence, in nuclear explosions, all visible colors are represented, and the fireballs are always white. The fact that Unit 3 is yellow is undeniable evidence that the explosion was chemical in nature.

PamW

[RobertEarl]

14. Maybe

But what we do know is that the core material itself was ejected into the air and around the world.

[FBaggins]

16. No... we don't "know" that at all.

The only thing that has been detected has been the more volitile elements that escape in venting and some heavier ones that have washed out with leaking water (into the ocean at least in the beginning).

There was no "core material ejected around the world".

[FBaggins]

15. And yet more errors.

1 is fine... 2 leaves off the actual damage caused (and there was an explosion), but isn't a big deal...

3... Huge explosion with dark colors in the clouds leading one to believe that the actual core itself exploded.

Leading one to believe? You don't by any chance thing that the fact that the RPV is still there and not, in fact, exploded makes that a pretty silly idea? I mean come on... some nuts online tried to sell this line over a year ago. When it actually was "too dangerous to approach" so they couldn't be as easily proven wrong... but it's been clearly wrong for quite some time now. Arnie's "prompt criticality" BS was ridiculous at the time... but now there's no doubt.

4... Core was empty. Fuel pool contained fresh spent fuel and building melted because of fires and excess heat.

Look... if you don't want to bother to pay attention, that's fine. But what makes you think you can just make stuff up and nobody will notice? The building never "melted". There was an explosion there on 3/15/11. Since there was no fuel in the core people (including many of us here) wondered where the hydrogen could have come from and speculation began around the possibility that it was from the SFP (and that was one of the reasons that pumping operations focused on that unit at the time). That speculation ended two weeks later when they got a chance to actually look into the pool. From that point on there was no doubt... yet over a year later you're making up nonsense about melting the building??? There are dozens of videos available for you to look up from inside that pool. There's absolutely no chance that there was an explosion in there. Zero.

Unit 3&4 shared a venting system. Hydrogen from unit 3 vented into parts of unit 4 and eventually exploded.

Plutonium from core #3 has been found spread around the world.

Nope. There's that "imagine" again. Plutonium doesn't come with labels of origin and has a very long half-life. The only way that you could possibly identify plutonium from Fukushima is to find it somewhere in greater concentrations than what already existed pre-fukushima. There is nowhere (off of the reactor site) where plutonium has been discovered in levels above what was already there from nuclear weapons (& their testing). On edit - you could tell the "age" of the plutonium to some extent by measuring the ingrowth of daughter elements. So that part is a little wrong. But the foundational point remains.

[RobertEarl]

17. Bullshit

Plutonium has been found in Europe and traced back to Fukushima.

See, around Chernobyl, the Europeans have set up sophisticated measuring devices.

Do some research, would be my advice.

[FBaggins]

18. Prove it.

Go ahead and provide a legitimate source for that claim (or was the title of the post just a label for what was to come?)

See, around Chernobyl, the Europeans have set up sophisticated measuring devices.

lol. You really don't "get" this stuff, do you?

"Sophisticated measuring devices" that can just sniff out plutonium, eh? It takes quite some time to weed out plutonium. You have to do the work back in the lab, you can't use air sampling devices that just set off an alarm when they detect PU.

I repeat what I said earlier (with some editing). The levels of plutonium detected "around the world" are consistent with already-existing levels and entirely inconsistent with the unit 3 explosion coming from within the core.

[RobertEarl]

19. Here ya go

Why you want to show how ignorant you are escapes me. Here is the pertinent info from a pdf I downloaded a month ago from:
journal homepage: www.elsevier.com/locate/jenvrad

Analyses of 131I, 137Cs and 134Cs in airborne aerosols were carried out in daily samples in Vilnius, Lithuania
after the Fukushima accident during the period of MarcheApril, 2011. The activity concentrations
of 131I and 137Cs ranged from 12 mBq/m3 and 1.4 mBq/m3 to 3700 mBq/m3 and 1040 mBq/m3, respectively.
The activity concentration of 239,240Pu in one aerosol sample collected from 23 March to 15 April, 2011
was found to be 44.5 nBq/m3. The two maxima found in radionuclide concentrations were related to
complicated long-range air mass transport from Japan across the Pacific, the North America and the
Atlantic Ocean to Central Europe as indicated by modelling. HYSPLIT backward trajectories and meteorological
data were applied for interpretation of activity variations of measured radionuclides observed
at the site of investigation. 7Be and 212Pb activity concentrations and their ratios were used as tracers of
vertical transport of air masses. Fukushima data were compared with the data obtained during the
Chernobyl accident and in the post Chernobyl period. The activity concentrations of 131I and 137Cs were
found to be by 4 orders of magnitude lower as compared to the Chernobyl accident. The activity ratio of
134Cs/137Cs was around 1 with small variations only. The activity ratio of 238Pu/239,240Pu in the aerosol
sample was 1.2, indicating a presence of the spent fuel of different origin than that of the Chernobyl
accident.

[FBaggins]

20. Still waiting.

The citation you give does not represent plutonium concentraions above those found all around the world pre-Fukushima.

The amount of plutonium released from fukushima is best estimated to be four orders of magnitude lower than Chernobyl. That's three core meltdowns but still four orders of magnitude off. It is therefore entirely impossible to claim that the core of #3 exploded and ejected the core into the air and all around the world.

[RobertEarl]

21. Read>> spent fuel

The activity ratio of 238Pu/239,240Pu in the aerosol
sample was 1.2, indicating a presence of the spent fuel of different origin than that of the Chernobyl
accident.

Lets see. Whom am I to believe.... a group of scientists who live near Chernonbyl and have built sophisticated sampling devices to ascertain nuke waste presence, or FBaggins?

And, golly, gosh, they sample near Chernobyl which is halfway around the world from Japan. Of course the presence of Chernobyl waste is gonna be greater than that from Japan.

[RobertEarl]

22. Other DU link about this

http://www.democraticunderground.com/1002583707

It's been fun. Thanks for the fish.

[RobertEarl]

23. Blast from the past n/t