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French nuclear firm trying to fix 'performance issue' at China plant
A French nuclear company has said it is working to resolve a "performance issue" at a plant it part-owns in China's southern Guangdong province after an earlier report of a potential leak there.
Framatome, a subsidiary of the energy giant EDF, told Agence France-Presse news agency that it was "supporting resolution of a performance issue" at the plant. "According to the data available, the plant is operating within the safety parameters," it said, adding that an extraordinary meeting of the power plant's board had been called "to present all the data and the necessary decisions".
The statement came shortly after the US TV network CNN reported that Framatome had previously warned the US energy department of an "imminent radiological threat" in a letter.
According to CNN, the letter included an accusation that the Chinese safety authority was "raising the acceptable limits for radiation detection outside the Taishan nuclear power plant in Guangdong province in order to avoid having to shut it down".
(Score: 4, Informative) by Anonymous Coward on Tuesday June 15 2021, @09:16AM (12 children)
I've read about this and there seems to be very little information. The emissions they talk about are from some noble gasses so probably Xenon. This is a normal gas created during fission. The problem they seem to have is that they have more of it than they expect. The main cause of this appears to be damaged fuel -- this is apparently normal to some extent but should not be ignored. When the amount of fission gas exceeds some level, they are suppose to stop ignoring it. The proper solution is to shut down the reactor and then to replace any damaged fuel assemblies. By damaged, I mean like cracked or whatever. But this takes weeks to months to do, you can't just turn it off and on again overnight.
From what I understand is that the Chinese just raised their release limit and say 'nothing is wrong here, more along'. So of course that raises concerns.
Now, the request from Framatome and EDF to US have to do with US laws about not using some technology they have to sidestep the issue without either releasing the gas to atmosphere (there is not that much, but it's still there which is not ideal especially since you can avoid it) or shutting down and refueling.
The concerns here are not that the reactor will blow up or is operated dangerously. The concern is that they are venting radioactive gas unnecessarily.
If you want a car analogy, it's like you are driving along and your tires are a little low on pressure. Now, you can stop and call roadside assistance and they will add your missing 2psi so you are perfect again but you will be late to work. At the same time you could press a button that will re-inflate your tires for you to perfect pressure but the tech is DRM and not available in your jurisdiction. So now you call the car company to pay the $5 to remove the DRM and inflate your tires, call roadside assistance or run your car less efficiently (pollute more) and spread more tire bits on the road (the tire is used more when underinflated)?
(Score: 2) by pe1rxq on Tuesday June 15 2021, @10:26AM (4 children)
Funny that your car analogy totally ignores the fact that the tire is leaking more than normal. All you options are basicly 'lets continue with the leaking tire, what is the worst that could happen'.
(Score: 3, Touché) by turgid on Tuesday June 15 2021, @10:28AM (2 children)
A blow-out leading to a serious accident, potentially with loss of life.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 2) by FatPhil on Tuesday June 15 2021, @11:44PM (1 child)
(Yes, I'm almost certainly doing the thing that I hate, namely explaining the joke. So upmod parent funny, not me. If that sounds strange to you and you thought this post was funny but parent post wasn't, then (a) evolve a more sophisticated sense of humour, you idiot; and (b) upmod parent anyway, you bleedin' idiot. Unless parent post wasn't subtle humour after all, in which case I expect turgid to chip in with a "what the buggery-bollocks are you blathering about, man?" comment hereafter. In which case upmod me.)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Wednesday June 16 2021, @01:37PM
I don't think GP was trying to be funny. I think he was stating a fact and you gave it a humorous spin (which I liked).
You know, it's interesting that over the past couple of years, a lot of people have very outspokenly said how safe the nuclear industry is (because all those accidents were either so long ago or the nuke plants that had problems were really old). We need to use nuke energy to save the planet, blah blah blah. Now, in this list of comments, it seems to swing the other way.
IMHO, nuclear energy can be safe to use in the short term, but we'll never get rid of the human element (and human greed) and to me, that's what makes it so frightening to use in the long term.
(Score: 0) by Anonymous Coward on Tuesday June 15 2021, @11:11AM
That's not a correct analogy. A leaking tire gets more dangerous as there is less and less air. This, on the other hand, is not necessarily progressing problem but sub-optimal state. Like they said, it's a performance issue. Basically, it's like you had perfect tire pressure and then temperature dropped by 40 degrees and your tires are running low on pressure. No leak, just needs more air to account for low temperature. And yes, this phenomenon happens all the time in places where temperature drops a lot in winter.
(Score: 2, Informative) by khallow on Tuesday June 15 2021, @12:58PM (4 children)
If so, looks like it would be Xenon-135 (Xe-135). It's a fission "poison" [stanford.edu], that is, readily captures low energy or "thermal" neutrons to form Xe-136, which normally gets "burned" in the reactor (to said Xe-136, but has complex dynamics [nuclear-power.net] in a reactor that is changing power generation levels). All else being equal, if it is building up in a reactor due to damaged fuel rods or some other cause, they would need to remove the gas (and apparently vent it), else it would eventually shut down the reaction due to excessive absorption of neutrons.
Glancing at Wikipedia, it appears that the primary decay path of Xe-135 (which has a half life of a bit over 6 hours) is via beta decay to Caesium-135 (Cs-135) which is mildly radioactive (half life of 2.3 million years) and apparently not a significant threat to human health in itself.
So if this scenario is correct, and not much else is being vented with the xenon, then it and its decay products are probably not much of a danger to the public.
My take is that the real concern here should be what else are they taking short cuts on? For example, if those fuel rods are damaged/cracked, were they damaged through normal use or some other reason? Are they otherwise doing the proper maintenance and inspections? This may be an indication of deeper problems not just with this reactor, but the entire Chinese nuclear power industry.
The usual Chinese opacity could be hiding some serious problems.
(Score: 2) by HiThere on Tuesday June 15 2021, @03:25PM
That seems accurate. They could be hiding a serious problem or a trivial one, and there's no way to tell which. This is to be expected in a bureaucracy where face-saving is very important. (The Chinese aren't the only practitioners of this ... process.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by Rich on Wednesday June 16 2021, @03:12AM (2 children)
To my understanding (I might be wrong), the zirconium tubes in which the fuel pellets are kept are hermetically sealed. Xenon-135 would not be vented at all, but go through the decay process and end up as solid. Certain reactors of eastern european origin had obscure entries in their manual that the reactor should not be re-started after a shutdown until after a waiting period (i.e. the xenon decay is over), and when some guy orders to ignore that, for example to repeat a safety test, shit can happen. There is no deliberate Xenon venting to accelerate the wait.
The industry eventually figured out that fuel elements DO break, not very often, but often enough, so they use scavengers to get the nasty stuff out of the primary coolant. As I read and understand the almost nonexistent press information, they have seen a lot more xenon than they have expected. Apparently they also reduced the power output. Putting one and one together, I assume they figured out that the fuel elements break at full load and came up with an engineering calculation how far they can push it. I would assume there is a predetermined breaking point for overpressure, so they might have hit that. If it is something else, it is bad. Control/safety rods might get stuck, which wouldn't mean an immediate meltdown, but they'd have to inject boric acid for a safety stop, and then the plant would be down for a major overhaul.
Also, this is all French technology. But I've been wondering why the EPRs at Olkiluoto, Flamanville, and Hinkley Point are major screwups, while Taishan went up on schedule. If the Chinese can ask Areva/EdF to straighten that out, that might cost the French more than they have. Then they'll demand nuclear subsidies from the EU, which might make people on course for the next German government VERY unhappy....
(Score: 1) by khallow on Wednesday June 16 2021, @12:41PM (1 child)
Not quite buying that. In a normally operating reactor, Xe-135 would absorb a neutron and become Xe-136 which is also a gas. If enough of that builds up, then your hermetically sealed fuel rods will rupture. But those rods get replaced regularly so I don't see it as a problem.
Looks like we have the answer to that. Because the Chinese are a bit more cavalier about such things like safety (and have a far weaker anti-nuke lobby).
Demanding something doesn't mean you'll get it. And China isn't operating in a way to minimize the cost of the resulting mess - that reduces any liability for France. They'll have a weak case for making demands, particularly, if the expertise and resources for cleaning up the mess has to come from outside China.
I don't quite understand the dynamics, but it sounds like you can get into some serious trouble when you do a quick restart after shutting down a reactor. In the few hours after the reactor is shutdown, Xe-135 would build up due to decay of other isotopes (which have a short half life as well). So you would temporarily have elevated levels of Xe-135 in the fuel rods.
Because Xe-135 is a strong fission poison, you have to run the reactor at significantly higher power (well, denser configuration of fuel rods) than normal in order to get the same level of fissioning - because the Xe-135 is absorbing a lot of the neutrons you would need to maintain criticality. Then once enough of the Xe-135 burns off (gets converted to Xe-136 by neutron absorption), the reactor will suddenly revert to normal criticality behavior with a substantial surge in power.
Maybe modern military nuclear reactors are designed to accommodate high Xe-135 operation (because you could be very dead, if you have to wait six or more hours to restart your nuclear reactor), but I doubt there are any civilian reactors designed for this sort of power surge, because you can save a lot of money and engineering by never operating the reactor in that way.
(Score: 2) by Rich on Wednesday June 16 2021, @01:21PM
I followed up, the tubes definitely should be fully sealed:
https://www.tandfonline.com/doi/pdf/10.1080/18811248.2010.9711953 [tandfonline.com]
Money quote:
This is for a CANDU, but I assume PWRs are not much different. PWRs also run at much higher pressures (300 bar), so a tiny bit of temporary gas buildup is completely irrelevant to the zircaloy tubes, even more so than in CANDUs. It seems the endcap sealing is a science in itself, so it's a good bet they assume these problems have to do something with those.
Haha. You have no idea how much German taxpayer money went down the drain to make issues go away, even when someone just was loudly whining. And when the French want the Germans to pay for their atomic mess, some green-aligned German heads will explode. They'll probably do a backroom deal and allow the ECB to "print" a few billion € for the French. (I'm simplifying, it's not called "print"ing anymore, I think the latest term was "quantitative easing").
This is designed in. The relevant discoveries about Xe-135 behaviour were made at Hanford (iirc, the Rhodes book is really good, they wondered why the reactor suddenly stopped) and Chernobyl (they wondered why the reactor suddenly blew up).
(Score: 0) by Anonymous Coward on Tuesday June 15 2021, @02:26PM
> I've read about this and there seems to be very little information.
So... move along, nothing to see here.
(Score: 0) by Anonymous Coward on Tuesday June 15 2021, @11:33PM
A better analogy would be a fouled catalytic converter. It doesn't affect the safety of the vehicle but it does cause unnecessary pollution and thus is in violation of the law.