Slashdot Mirror
China Goes Nuclear
Rei writes "Wired reports that the People's Republic of China has announced plans to build 30 new nuclear reactors by the year 2020, and by 2050 have almost as much nuclear power as the entire world produces today. The reactors are to be pebble bed reactors, in which helium replaces radioactive, pressurized water. A Chinese research institution demonstrated the safety of their test reactor against meltdown by shutting off the coolant."
Not only does nuclear energy work, but it is a major source of power all over Europe. For instance, France currently generates 75% of its total power from nuclear sources (from this BBC story). Like many things, nuclear power can be a good thing if it is generated safely, and it can be very dangerous if not. The key is to be safe in how the nuclear power plant is built, operated and maintained.
Coal releases more radioactivity that nuclear power anyway.
From this article, "the population effective dose equivalent from coal plants is 100 times that from nuclear plants."
Read up on the reactor design they're using, Pebble Bed Reactors.
These are not your traditional nuclear reactors, they don't suffer from a run-away failure mode, they're designed such that even if all control rods are removed and the coolant gets shut off the increased temperature itself slows down the reaction to a stable idle - below the temperature at which the fuel or reactor melts. Ie they inherently can't blow up or go into meltdown.
Additionally the coolant used is helium, an atom that has very low neutron absorbtion, meaning in the case of a leak there is no atmospheric or groundwater contamination.
Additionlly-additionally the nuclear fuel is at a much lower density, compared to a conventional reactor, greatly simplifying refueling and disposal. Each 210 g pebble contains 9g of uranium grains, sealed inside an exetremely tough ceramic casing that doesn't burn or break - hence no radioactive dust or smoke in an accident.
These things seem very safe and very clean. My main concern will be the lack of public criticism and independant oversight in a country such as China.
Alex
It's also important to note WHY it's safe to shut off the cooling system. Pebble bed reactors are LESS reactive without the coolant, therefore they 'starve' themselves if they overheat (yeah that was for the layman). Thus it is safe to remove the coolant from a pebble bed reactor.
I know a bit about Yucca Mountian. My uncle was a concrete engineer working on lining the whole damn place with spray concrete. (got some awesome pictures), and I know the guys the designed those containers to be stored there, and I also know the guys the designed the filters to trap those heavy metals, once they become water borne.
MOST of the stuff disposed there is cleanup stuff. Cloths. Rags. Containers. ***REALLY*** mundane stuff. The next biggest percentage is those filters that I mentioned earlier. Every ounce of radioactive non-volatile fluid to be buried is first run through what basically amounts to a HEPA filter for water. So, those particulates infact become solid waste. What's left of the water is boiled off, and the remnants get packaged too (mostly regular mineral deposits)
The high level wastes are encapsulated in glass or copper in such amounts that there is not enough for that material, or it's decomposited forms to cause a situation of critical mass. Lots of radioactive stuff in one spot can cause quite alot of heat, right? So they limit the quantities of high level radioactive waste to a certian amount PER CONTAINER. Fortunately, Very very very very *VERY* little of what is buried is this form of waste. Less than 20%, and maybe 2% of any given container is highly radioactive... And quite honestly, most of the stuff they treat like this does not at all really need to be treated so carefully.
If Carter's nuclear recycling ban was lifted, that 20% number could be easily dropped to 5% or probably less.
Chill friend. First off I was pointing out the insanity of someone saying we can just bury it, and the insanity that is Yucca Mountain which is basically just burying it.
Reprocessing it is a whole different and more complicated thing. The issue with reprocessing are so complicated and varied you aren't going to do it justice in a Slashdot thread.
Depending on the methods you choose you still get waste of various forms, different waste sure, but there is still a lot of waste from reprocessing. In particular you are going to get plutonium of various grades from weapons grade to plutonium suitable for fast breeder reactors. The only way you get rid of the plutonium waste in the near term is to put in bombs or burn it in reactors designed to burn it.
A key reason reprocessing has such a stigma attached to it is its historically and still is in some places used to harvest weapons grade plutonium. It is a key avenue for nuclear weapons proliferation and weapons grade plutonium is far more dangerous in the wrong hands than the waste so its not like you want every country on the planet doing it.
There is some value in the way reprocessing its being used in France, India and Japan to recycle the fuel and reuse it in fast breeder reactors but there a whole set of issues with that path two.
Pyroprocessing is the new holy grail and it might prove to be a better route than the current PUREX and UREX reprocessing but its not exactly a proven process and it a potential accident waiting to happen too.
Here is a technical brief on the methods though its written by a pro nuke group and needs to be taken with a grain of salt.
You might be able to reduce the dangerous lifespan of a of of waste to 500-1000 years, and burn some of it in reactors but to hold it out as the final solution to nuclear waste is a stretch at this point.
@de_machina
Natural uranium is only slightly radioactive. It has to by mined in huge quantities and purified to produce weapons grade uranium and reactor fuel.
Most of the waste we are talking about here isn't uranium, its plutonium and a host of other exotic metals and isotopes. Plutonium is lethal in extremely small quantities, and with reprocessing its highly sought after to produce nuclear weapons or dirty bombs. You can't just dump it back in a whole in the ground. Like most things you dump in the ground there is a high probability some of its going to end up in the ground water which people drink, and is used in agriculture to grow food for people to eat.
@de_machina
> This is startlingly good news for Nevada.
> Scientists have always said that Yucca Mountain
> was a disaster-in-the-making, even leaving aside
> those 50 million Americans living within half a
> mile of the shipment routes the Yucca-bound
> nuclear waste would travel on for decades to come,
> or the 90 to 500 estimated accidents of unknown
> scale that statistics suggest would take place en
> route over the years. (Who needs terrorist dirty
> bombs when our own tax dollars can supply them?
I call FUD. Have you *seen* the containers that they've created to hold the nuclear waste? They've taken them and rammed them into walls at 80 MPH on the top of tanker trucks, dropped them on large iron spikes, fired SAM missles at them - all to no avail. Hardly made a dent in them.
These things are multi-million dollar containers that are about an order of magnitude thicker than your average tank. Given that they are going to be escorted by police and military convoys, I sincerely doubt that anything serious is going to happen.
I truly worry about the US if we let ourselves fall behind on this - misplaced anxiety is really going to do us in in the next century. I can only hope that calmer heads prevail.
horos
Geez. Another one. Please get an education in physics or read the radiation hazard page at Wikipedia. The worst part of the waste is not the one with the long half-life elements (i.e. Plutonium, Uranium). But the short half-life elements (Iodine-131, Strontium-90).
Usually the faster something decays, the more radiation it releases per unit of time. Something that takes a long time to decay is usually just somewhat warm to the touch. Like plutonium.
The ultimate proof of course, is that elements with an infinite half-life (want even higher half-life than that?) like Au-197 (plain Gold) emit zero radiation.
If you just leave the waste in a pile, it will eventually be a very pure tolerable radiation hazard uranium + plutonium mine and a very valuable resource. The shorter half-life elements will have decayed already.
Regarding Plutonium toxicity, it is way overblown. Sure it is a heavy metal, so is Lead, yet we don't get into a hissy fit about it. Last I heard, they still used Lead to make solder. You aren't going to be allowed to make plates and forks from the stuff, or have it in easily inhalable or drinkable powdered or soluble form (like they used to have in Gasoline), but as long as you use proper procedure it is not that big a deal.