Danger of Spent Fuel Outweighs Reactor Threat

[OKIsItJustMe]

http://www.nytimes.com/2011/03/18/world/asia/18spent.html?src=tptw

Danger of Spent Fuel Outweighs Reactor Threat

By KEITH BRADSHER and HIROKO TABUCHI
Published: March 17, 2011

Years of procrastination in deciding on long-term disposal of highly radioactive fuel rods from nuclear reactors is now coming back to haunt Japanese authorities as they try to control fires and explosions at the stricken Fukushima Daiichi Nuclear Power Station.

Some countries have tried to limit the number of spent fuel rods that accumulate at nuclear power plants — Germany stores them in costly casks, for example, while Chinese nuclear reactors send them to a desert storage compound in western China’s Gansu province. But Japan, like the United States, has kept ever larger numbers of spent fuel rods in temporary storage pools at the power plants, where they can be guarded with the same security provided for the power plant.

Figures provided by Tokyo Electric Power on Thursday show that most of the dangerous uranium at the power plant is actually in the spent fuel rods, not the reactor cores themselves. The electric utility said that a total of 11,195 spent fuel rod assemblies were stored at the site.

That is in addition to 400 to 600 fuel rod assemblies that had been in active service in each of the three troubled reactors. In other words, the vast majority of the fuel assemblies at the troubled reactors are in the storage pools, not the reactors.

…

[FBaggins]

1. They're certainly dangerous... but this article makes some serious errors.

The most substantial of which is the statement "Years of procrastination in deciding on long-term disposal of highly radioactive fuel rods from nuclear reactors is now coming back to haunt Japanese authorities "

I've heard some PRO nukes make this same error.

No matter what you do with long-term disposal, reactor fuel must sit in a fiel pool for a few years to cool down. By the time it's ready for long-term disposal, the issues we're talking about now aren't really a danger. The won't overheat or catch on fire. Japan could have the world's best magical long-term storage site and there would still be five years worth of spent fuel in those pools.



There are reasons to put more effort into long-term storage of nuclear fuel (whether you're pro or anti nuke... but nothing in the current events has anything to do with that.

[DCKit]

2. I understood the article to say something more like:

"Don't store the gasoline on top of the incinerator."

[FBaggins]

3. Putting it somewhere else would cause other dangers.

We need to make sure that whatever design changes we contemplate for the future, we don't focus in on it as if Tsunami are the only dangers for reactors.

If the fuel pool isn't here, you need to transport fuel newly out of the reactor building and to a different pool. That obviously raises entirely new concerns.

But back to your point... that really isn't a "long-term storage" issue.

[spin]

4. Well put! (n/t)

[abqmufc]

5. Great point!!!

The point you bring up (spent fuel must stay onsite till it is stable enough to be transported to long-term storage) is one I always bring up in the Yucca debate. Just b/c we open a long-term storage, does not mean a State gets rid of its nuclear waste issue. So long as we have nuclear weapons and nuclear power we will always have waste being produced.

That being said, looking at this country's debate over nuclear power the fact we as a Nation have gone down the road of the nuclear era with no long-term solution to storing nuclear waste is the most basic argument against nuclear power.

Yucca was one of three parts of the nuclear cycle I based my graduate work on in public policy. Yucca is flawed as it is a dormant volcano, on a fault line, the geology is terrible, it's sacred to 13 Tribes, and NIMBY attitudes extend through out the Southwest. What once was a sparsely populated part of the country (ideal for nuclear waste storage and development of the nuclear era) is now the fastest growing part of the country (Vegas, Phoenix, Santa Fe). Unfortunately the Yucca option is back on the table in Congress.

IMO the USA should have stopped the rapid development of the Southwest. The day A/c came to places like Phoenix, Tucson, Vegas, to name a few, was the day everyone decided it was not such a bad place to live year round. I suspect Hanford may become the longterm storage facility at the end of the day. I think the population is more likely to accept waste considering the entire facility is now a waste site. People have lived with the impacts since the 40s and there is not a rapid population growth like there is surrounding Yucca.

[OKIsItJustMe]

7. "a few years" = 20?

http://theautomaticearth.blogspot.com/

Tuesday, March 15, 2011

March 15 2011: The Fukushima Fallout Files

Ilargi: The Automatic Earth's senior editor Stoneleigh is a nuclear safety expert. The subject of her master thesis at the Law Faculty of Warwick University in Coventry, England, was nuclear safety research.

After graduating in 1997, she became a Research Fellow at the Oxford Institute for Energy Studies, where her research field was power systems, with a specific focus on nuclear safety in Eastern Europe.

The monograph she wrote sets the nuclear safety debate in the political and economic context of the collapse of the Soviet Union. It was published in 1999 under the title Nuclear Safety and International Governance: Russia and Eastern Europe, and it remains available online here at the http://www.oxfordenergy.org/pdfs/SP11.pdf">Oxford Institute for Energy Studies.

Stoneleigh:

The Fukushima Fallout Files

…

Spent fuel also requires constant cooling in a separate pool, and we are beginning to see problems with its storage at Fukushima 1. The explosion at unit 4 appears to have involved a cooling pool, with water levels dropping. There is considerably more radiation contained in the spent fuel than in the reactor cores, and spent fuel can also suffer a meltdown if cooling cannot be maintained. There are seven spent fuel pools at Fukushima 1, many of them densely packed with some 20 years worth of spent fuel. (All spent fuel world-wide is stored in this way, near the reactors which produce it, as no country has yet developed and implemented a long-term storage solution for waste that will remain radioactive for thousands of years.)

…

[FBaggins]

8. It equals at least five IIRC...

...but it can go as long as they want (assuming room in the pool).

But it isn't that big a deal either way. Once the fuel is cool enough for long-term storage, it doesn't put out much heat.

You could have 20 years worth of fuel in that pool and if it were all a few years old... it wouldn't heat up enough to catch fire. You don't get much decay heat when there isn't much decay going on. That's where they got a little lucky in #3 and unlucky in #4. #3 was refueled nine months ago, so there isn't any fresh fuel in the pool. #4 (I think) was being refueled.

[OKIsItJustMe]

9. “Experts” say it can catch fire. I hope we won’t see events prove you wrong.

http://www.reuters.com/article/2011/03/15/us-japan-nuclear-pools-idUSTRE72E6OL20110315

Analysis: Spent reactor fuel opens new risks in Japan crisis

By Scott DiSavino

NEW YORK | Tue Mar 15, 2011 1:35pm EDT

NEW YORK (Reuters) - A fire and blast at the building protecting a massive pool holding spent atomic fuel has taken Japan's nuclear crisis to a more critical level.

…

The pools of spent fuel are dangerous for two reasons: they are more easily exposed to the atmosphere because they don't have the feet-thick containment wall that protects the nuclear core; the building housing the pool has already suffered hydrogen gas explosions and is open to the sky in places.

They also hold far more radioactive elements that could quickly heat up again if water burns off. Experts worry that this could expose the used nuclear fuel and start a fire that would release more radioactivity.

…

The rods contain radioactive cesium, strontium and plutonium. When a rod is exposed to the air the zirconium metal on the rods will set on fire, which could release the radiation, said Gundersen.

…

[FBaggins]

10. They're talking about the more recent fuel.

Ten-year old stuff would be warm to the touch, but would get hot enough to burn. It's the radioactive (fresher) stuff that they're worried about.

[WingDinger]

6. My father proposed to Rockwell, that they jetisson it into space.

Towards the sun. In fact, the mission of the Space Shuttle directly after the one that blew up, was slated to contain 90 lbs of plutonium. Needless to say, that was nixed. 90 lbs is enough to give every man and woman cancer if distributed evenly.

[phantom power]

11. $5000 per pound to low earth orbit.

That's just to orbit. That isn't out of our gravity well.

Fukushima has over 600 tons of fuel.

[WingDinger]

14. space elevator?

[mackdaddy]

12. Would the massive explosions not spread these "spent" rods??

I have not way of verifying this, but I think the following is true:

-The towers are each 1000 feet tall. They look like transmitter towers, but are there to keep airplanes away.
-The first explosion last Friday of the #1 reactor blew debris at least as high as the tower.
-The Second explosion two days later made a mushroom cloud three times the height of the tower.
-Large chunks of debris were visible being blown out of the top of the mushroom cloud.
-There have been more explosions and fires since these first two large explosions, but not caught on video.
-Many recent photos have shown the tops of the buildings of the first three reactors completely destroyed.
-These thousands and thousands of "spent" rods are stored in swimming pool size storage pools on "top of" the reactors themselves.
-At least the #3 reactor is run by a mix of 6%Plutonium in with the uranium as fuel.

What I have not been able to determine but I believe is:
- that the blown up/ burnt up portion of theses square buildings IS the outer containment building.
-The spent fuel cooling pools are now open the the atmosphere.
-Some of these fuel rods could have been, or were blown up and may have been spread across the entire complex and surrounding area in these massive explosions.
-These pool have been at a minimum damaged, and at worst will no longer hold water literally.
-One report had one of the pools missing one entire wall.
-Some of these "spent" fuel rods will still get hot enough to catch fire on their own.
-
-No matter what, superheated steam containing various radioactive particles is constantly being vented from ALL of the reactors.

OK, So where do I have this wrong? It is very damn difficult to parse the reports.

[FBaggins]

13. If there were massive explosions, yes.

On edit - My apologies. I thought your questions replied to my earlier post. Some of this won't make sense without that post.



I'm not sure what the theory is behind "explosions", but a significant fire would be bad enough. And presumably, yes... the less active fuel could get caught up in that.

Now... the cladding on the fresh fuel would be the first to go (the older fuel wouldn't get as hot), so it then has to burn through the cladding on the older fuel...


...but the end result isn't all that substantially changed. The 15-year old fuel simply isn't as radioactive as the fresher fuel. So yeah it could be spread in one of these theoretical examples, but it's still not as dangerous.

-At least the #3 reactor is run by a mix of 6%Plutonium in with the uranium as fuel.

It was the first unit to get MOX fuel (I think the first in all of Japan) last Fall... so it hasn't been refueled yet (which means that all of the MOX is in the core).

OTOH, spent reactor fuel does contain plutonium anyway.


What I have not been able to determine but I believe is:
- that the blown up/ burnt up portion of theses square buildings IS the outer containment building.

Not most of it. Unit #4 appears to have lost an entire wall, but the rest of the damage appears to be the comparatively lightweight structure on top of the containment.

-The spent fuel cooling pools are now open the the atmosphere.

With the exception of a bunch of debris, yes.

-Some of these fuel rods could have been, or were blown up and may have been spread across the entire complex and surrounding area in these massive explosions.

The pools would have had to be dry first for that to happen. Water is not very compressible and would be an excellent protection against an explosion.

-No matter what, superheated steam containing various radioactive particles is constantly being vented from ALL of the reactors.

Yes (though not necessarily "superheated"). In the case of #2 (which lost at least its torus) that's particularly dangerous because it's possible that it isn't being released through a filter and may contain more elements. A very high percentage of the radioactivity in that steam comes from a very small portion of it that reacted with radiation inside the core. This results in an element that is highly radioactive, but also has a very short half-life (the two mean the same thing of course). Most of that radiation is gone within minutes.

As long as the bulk of the output from these units is made up of this steam, we will continue to see transient high levels of radiation in and around the plant, but much lower levels elsewhere. That wasn't the case with, for instance, Chernobyl. The open core combined with the fire expelled a very different mix of elements. Many of which were heavier and had comparatively long half-lives. So you could have areas 100 miles away with dangerous levels of radiation while another area half as far away isn't nearly as bad.

[caraher]

15. It is difficult

Here's what's "under the hood:"



This is a "Mark I" containment system. The vertical cylinder is the reactor with the active fuel, and it's surrounded by a steel pressure vessel and I believe reinforced concrete containment. The spent fuel storage is beneath the crane and to the right of the top of the pressure vessel in this picture, and this is outside containment (the rest of the building structure is not designed to be a containment barrier). So the first thing you're unsure of is wrong - the blown up part is not the outer containment. But in a way it might as well have been, since its loss exposes the spent fuel storage area (your second item, which is basically right.)

The rest of what you say is pretty accurate. The very last thing is untrue only in an irrelevant sense - steam does need to be vented regularly, but not necessarily continuously. This will have to continue until either someone finds a way to restore normal cooling (assuming that's even possible) or until there's enough decay that the heating no longer generates pressures that threaten reactor vessel integrity. Or until a full-on meltdown.

[caraher]

16. Captioned version of figure

From the Union of Concerned Scientists