Great. Now officials are saying that the storage pools, where every nuclear power plant stores spent radioactive fuel, have experienced a fire and may be boiling. My understanding of spent fuel is that it won’t boil the water, so I have a feeling there’s misunderstanding here. However, a fire at one of the storage pools would be a very bad thing, and would seriously increase radiation levels if that fire created steam.
If there’s one thing that is unsafe about nuclear power it’s the practice of storing waste on the site of the plant in containers that aren’t as over-engineered as the reactor. But this is not an engineering problem, it’s a political one. This issue is one that’s been made by the hippies and politicians, since there are safe solutions to this problem, but the hippies and politicians refuse to allow government to implement those solutions. The same hippies and politicians will now use this as evidence that nuclear power cannot be made safe, and that we should stop building new plants, since we can get all our energy from flowers and unicorn farts, or something like that.
It’s enough to make my inner engineer weep if I think about it for too long.
If your inner engineer weeps, and you don’t have a license can you be charged for practicing engineering without a license?
There is a better solution than transporting hot waste to Yucca Mountain, breeder reactors, breeder reactors should be mandated at every nuclear reactor in the US, then the fuel stays on site.
There is enough fuel on site to run all the US plants for a thousand years….and it is almost a complete non issue disposing of the non fuel byproducts.
Oh yeah, and to start off this program, Jimmy Carter should be pushed into an active storage pond on live TV for what he did to the US Nuclear program in the 70’s.
The problem with breeders is that you need fast neutrons in order to breed fuel. In order to get fast neutrons, you have to use a liquid metal coolants, which presents serious engineering problems on a large scale reactor that you’re going to use to make power, at least if you’re going to use a uranium fuel cycle. You can do a heavy water reactor with thorium, but the problem there is we don’t have proven designs that work with a thorium fuel cycle. That’s one thing that ought to be researched, however.
How secure is the storage pool area from tsunami-splashed diesel fuel?
How hard is it for a stray spark to ignite splashed diesel fuel?
I’m not saying it’s happened, I’m just saying it’s the first thing that came to mind.
I’m sorry I made a mistake in my terminology (armchair engineering, graduated from KKST – Keyboard Komandos School of Technology),
I meant Electrolysis/Electrorefining/Electrowinning the the fuel on site…..
I don’t think it’s that easy to get diesel burning.
“But this is not an engineering problem, it’s a political one.”
No, it’s both, as well as being an economical problem.
“This issue is one that’s been made by the hippies and politicians, since there are safe solutions to this problem, but the hippies and politicians refuse to allow government to implement those solutions. ”
Um, it’s also been made by the operators of nuke power plants. Your “safe solution” is to give the nuclear waste to the government and let it deal with it. The federal government is not a reliable actor and it can not be credibly trusted with such a responsibility. Add in the short half-life of governments and the long half-life of the waste and it doesn’t make any sense.
Japan has a fast breeder (although its checkered history indeed shows there’s more than political problems with that approach) and I remember their having a batch of fuel reprocessed by the French (with the usual insane “reactor grade plutonium could be captured by terrorists to make a bomb!!!” garbage). In relation to this crisis Fukushima Daiichi Unit 3 is loaded with MOX fuel.
Especially given the placement of the storage pools I suspect they’re just being used to let the rods cool down/decay for a bit before being sent for reprocessing.
karrde: No idea, and effectively impossible, in that order.
Diesel fuel does not have explosive vapor in anything like normal conditions, unlike gasoline.
One can literally drop a lit match into a bucket of diesel fuel at normal temperatures, and all it’ll do is put the match out.
(Now, if it was already very hot, I’m sure the heated diesel vapor would ignite more easily, but if it was that hot, you wouldn’t need a diesel fire to boil off the water…)
I’d be fine with a private solution too, but to some degree you’re going to need federal involvement when all the states balk at shipping waste through their states by rail.
if the storage pool is/was damaged and the water was allowed to evaporate/boil/leak out until the spent fuel is uncovered even partially then the rods will heat up and the zirconium cladding will burn within hours.
this can progress until a return to criticality event creates a local explosion that then will then self regulate back to just heat and smoke.
but the spread of cesium 137 has cancer potential depending on where it goes (hence the iodine being handed out)
see http://www.microsimtech.com/sfpquiz/default.htm
Without outside mechanical damage (note the linked test’s use of “cask drop”) how likely is a Spent Fuel Pool to go critical? How likely is a molten pool of corium to form (that would be bad, seeing as how it’s not behind much containment) or go critical in a big way (that would be much worse, of course)?
Wouldn’t it be pretty easy to guard against the last possibility? E.g. arrange the geometry of the concrete underneath into small cells, sort of like this: |_|_|_|_| (not to scale, the vertical walls need to be thick).
I must say that as I’ve studied all this more seriously in the last few years my respect for nuclear engineers has gone up and up.
When refueling a reactor, only about one third of the fuel is removed (2/3 still has usable fuel left in it – i.e. the nuclear poison buildup has not degraded the uranium/plutonium beyond the rate of return). However, in Japan during refueling outages they typically offload all of the fuel to have better access to the entire under core area.
The storage pool still has to have circulating water in it to maintain it cool, the heat up rate without that circulating water is dependent on how much fuel is in the pool and how old that fuel is.
@Patriot Henry, the government has always mandated that they be the ones responsible for the spent fuel. Industry wasn’t given that option. If they had have been, the problem most likely would have been solved by the end of the 60s at a fraction of the cost that the government has spent AND would have been both secure and available for future breeder technology.
Reputo: One nit: won’t these thermally hot rods provide their own circulation of the water through convection?
Obviously you need more than that to keep the pool happy, but my thought here is that if the water is boiling off if you can just add more water (ideally before the tops of the rods get exposed) then things will be OK.
With regards to Yucca Mountain, I would have to add: this would only be a solution if we remove the ridiculous ban on recycling spent fuel. As it stands, Yucca Mountain cannot contain all the nuclear “waste” our own reactors have–but, if we can remove the real waste and store that, it would take a very long time to fill Yucca Mountain.
But laws currently stand in the way of recycling the rods!
@ Harold. Yes partly, the convection will transfer heat, the problem you have in Japan is adding water that has boiled off. If the spent fuel pool is still intact, then you have 30 ft of water to boil off until you get the rods uncovered. If there has been any kind of a breech, then that water level could be lower.
The other problem with relying on the natural convection for the pool is there is no convective circulation. So at the bottom of the rods, a bubble forms, it is small because it is under 45 feet of water, as it rises up along the fuel rod it starts to grow and progressively expands as pressure decreases (due to lower head pressure). Parts of the fuel rod are not covered with water as the steam bubble passes by. Since steam has a lower heat transfer capacity than liquid water, you have locally increasing temperature on your fuel rods. This then causes faster boiling. Ergo, the process repeats itself only more so. Eventually, you can get to a point where there is rapid boiling all around the fuel rods, and the liquid can’t replace the steam fast enough to slow down the rise in temperature of the fuel rods. Once the bulk temperature of the water is near boiling, it is just a matter of time until the water is gone.
Iddeally, you want to be putting cooler water (80 degrees or less) into the pool so that you can prevent localized boiling at the surface of the rods.