Foreign Press Warns Of Potential Catastrophe At Fukushima No. 4 Reactor

[robert l. bentham]

More than a year after a devastating earthquake and tsunami triggered a massive nuclear disaster, experts are warning that Japan isn't out of the woods yet and the worst nuclear storm the world has ever seen could be just one earthquake away from reality.
The troubled Reactor 4 at the Fukushima Daiichi nuclear plant is at the centre of this potential catastrophe.
Reactor 4 -- and to a lesser extent Reactor 3 -- still hold large quantities of cooling waters surrounding spent nuclear fuel, all bound by a fragile concrete pool located 30 metres above the ground, and exposed to the elements.
A magnitude 7 or 7.5 earthquake would likely fracture that pool, and disaster would ensue, says Arnie Gundersen, a nuclear engineer with Fairewinds Energy Education who has visited the site.
The 1,535 spent fuel rods would become exposed to the air and would likely catch fire, with the most-recently added fuel rods igniting first.
The incredible heat generated from that blaze, Gundersen said, could then ignite the older fuel in the cooling pool, causing a massive oxygen-eating radiological fire that could not be extinguished with water.
"So the fear is the newest fuel could begin to burn and then we'd have a conflagration of the whole pool because it would become hotter and hotter. The health consequences of that are beyond where science has ever gone before," Gundersen told CTVNews.ca in an interview from his home in Vermont.
There are a couple of possible outcomes, Gundersen said.
Highly radioactive cesium and strontium isotopes would likely go airborne and "volatilize" --turning into a vapour that could move with the wind, potentially travelling thousands of kilometres from the source.
The size of those particles would determine whether they remained in Japan, or made their way to the rest of Asia and other continents.

http://crooksandliars.com/susie-madrak/foreign-press-warns-potential-catastr

 

[ilwrath]

Reactor 4 -- and to a lesser extent Reactor 3 -- still hold large quantities of cooling waters surrounding spent nuclear fuel, all bound by a fragile concrete pool located 30 metres above the ground, and exposed to the elements.

Well, correct me if I'm wrong... But, as I understand it, the only difference between now, and standard operating procedure, in this respect, is that the flimsy reactor building surrounding the concrete vats is now missing. It was "normal" for this plant layout to use the vats for holding spent fuel rods. They just sit around in water, cooling. These vats are located around the bottom of the reactor core. And, in fact, the fuel rods are sitting in exactly the same "fragile concrete pool" where they were before the quake and tsunami.

So while the potential for problems is quite frightening, it's not really any more so than it was before. (Other than decommissioning will be hard, as the buildings are a mess.) This is part of the reason why these older nuclear plants had "decommission by" dates on them. It drives me nuts that here in the US we don't build new plants, while extending the lifetime deadline on the old ones. That's the worst possible thing to do, if you're legitimately concerned for safety.

 

[FluffyMcDeath]

Well, correct me if I'm wrong...

OK.

It was "normal" for this plant layout to use the vats for holding spent fuel rods.

Normal-ish. The fuel pools were for temporary storage of hot fuel (fuel recently extracted that is full of daughter products that are decaying and producing radiation and heat). They weren't meant to store fuel indefinitely.

They just sit around in water, cooling.

They need active cooling. The water has to be circulated else it will boil away leaving the fuel rods exposed.

These vats are located around the bottom of the reactor core.

Now here's where your tires start to lose traction. The fuel pools are located at the TOP of the reactor. This was done in order to reduce the exposure time of hot fuel when unloading the reactor. However, the fuel pools are very heavy - water weighs a ton per cubic meter, but the fuel is much heavier than that. Plus the entire structure has been weakened by the quake and subsequent quakes. If it were to spring a significant leak, or worse, completely fall over in a big quake, then the rods would no longer be cooled and they would no longer be shielded. The resultant radiation would be enough to make it impossible for crews to come near to deal with the problem and the rods would start to heat up. When they get hot enough the cladding metal on the rods will ignite and it will be one of those metal fires that just gets worse if you try spraying water on it. That will put enormous amounts of radioactive material into the air and will probably result in the evacuation of Japan - though North America won't be much better off and the oceans will be thoroughly irradiated. The plutonium and uranium won't likely reach us by air in significant quantities (though enough to put up the cancer rates) and the cesium that makes it over will contaminate agricultural land for 300 years.

It drives me nuts that here in the US we don't build new plants, while extending the lifetime deadline on the old ones. That's the worst possible thing to do, if you're legitimately concerned for safety.

The nuclear power industry is very profitable - more so if you cut corners. This is what will ensure that nuclear power is never safe. Arnie knows his stuff when it comes to flawed designs, but ask Greg Palast about just plain old cheating on inspections. Most of the plants int he US are on the verge of falling apart - even the newer ones.

 

[Glaucus]

The nuclear power industry is very profitable - more so if you cut corners. This is what will ensure that nuclear power is never safe. Arnie knows his stuff when it comes to flawed designs, but ask Greg Palast about just plain old cheating on inspections. Most of the plants int he US are on the verge of falling apart - even the newer ones.

But this is an issue of governance, not technology. From a technical point of view, phasing out old reactors and building newer reactors is a step forward. Even with bad governance, the new style reactors are designed to better handle a catastrophe, where as the old ones relied more on active warning and cooling systems to prevent a catastrophe.

 

[ilwrath]

OK.

That's why I love this place.

Normal-ish. The fuel pools were for temporary storage of hot fuel (fuel recently extracted that is full of daughter products that are decaying and producing radiation and heat). They weren't meant to store fuel indefinitely.

They need active cooling. The water has to be circulated else it will boil away leaving the fuel rods exposed.

Yes, I should have been more specific here. I didn't mean that they were just sitting in a little puddle. It's a big-ass vat that absolutely needs constant circulation. That was one of the immediate problems after the tsunami, the plant had no power, damaged pumps, and no circulation in these vats.

Now here's where your tires start to lose traction. The fuel pools are located at the TOP of the reactor. This was done in order to reduce the exposure time of hot fuel when unloading the reactor.

That totally makes sense... but every diagram I've seen shows them at the bottom.? Or am I looking at the wrong vats? As you mention, there are two sets. The short-term holding for the hottest rods, and the longer term holding once they've dropped to a specified radiation level. Both require circulation and are onsite and near the reactors.

However, the fuel pools are very heavy - water weighs a ton per cubic meter, but the fuel is much heavier than that. Plus the entire structure has been weakened by the quake and subsequent quakes. If it were to spring a significant leak, or worse, completely fall over in a big quake, then the rods would no longer be cooled and they would no longer be shielded. The resultant radiation would be enough to make it impossible for crews to come near to deal with the problem and the rods would start to heat up. When they get hot enough the cladding metal on the rods will ignite and it will be one of those metal fires that just gets worse if you try spraying water on it. That will put enormous amounts of radioactive material into the air and will probably result in the evacuation of Japan - though North America won't be much better off and the oceans will be thoroughly irradiated. The plutonium and uranium won't likely reach us by air in significant quantities (though enough to put up the cancer rates) and the cesium that makes it over will contaminate agricultural land for 300 years.

Yup. But again, this is the same basic problem this design always had.

The nuclear power industry is very profitable - more so if you cut corners. This is what will ensure that nuclear power is never safe. Arnie knows his stuff when it comes to flawed designs, but ask Greg Palast about just plain old cheating on inspections. Most of the plants int he US are on the verge of falling apart - even the newer ones.

Well, even the "newer" ones are nearing or past their original decommission dates. :/

 

[FluffyMcDeath]

That totally makes sense... but every diagram I've seen shows them at the bottom.? Or am I looking at the wrong vats?

Perhaps. Anyway here's a fairly clear cutaway of a GE Mark 1 which is the kind that they lost several of at Fukushima.

The orange thing at the top is the crane (at one of the reactors this crane has fallen into the fuel pool). At the bottom left is the access by which new fuel comes in - and old fuel would go out if they ever took the old fuel out.
Under the crane is the spent fuel pool. You can see that it would actually be possible to take the fuel from the reactor and move it to the fuel pool while keeping it submerged all the time. This helps to prevent the workers from getting on overdose of death rays.

Those are the only fuel pools and that is where all the spent fuel is. The torus down below is for quenching steam in the event of a flash event, if the reactor gets a little too hot and needs to blow off some steam.

As you mention, there are two sets. The short-term holding for the hottest rods, and the longer term holding once they've dropped to a specified radiation level.

There is one set. The fuel has been building up there over the years., There are no other storage facilities on site or off. You make more money by delaying these sorts of things as long as possible.

Yup. But again, this is the same basic problem this design always had.

Except the design has been modified - by a big quake, several explosions and a release of radiation that has the place so hot that it is difficult to work around and keep crews alive. The structures have been damaged and nobody knows how many quakes of what size they can still withstand before failing catastrophically. It may never happen but then again if it does happen it will likely be beyond their technical capacity to control the aftermath. However, the longer the fuel stays up there the more likely it is that something bad will happen before it's safely down - and yet some of it is still very hot and therefore not at all easy to move.

Well, even the "newer" ones are nearing or past their original decommission dates. :/

They should all be decommissioned. Nuclear is a small part of the industry and could be replaced with solar and wind. At least a windmill failure won't contaminate hundreds of square kilometers rendering the land unusable for 300 years.