It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Cables highlight the regulation weaknesses that permitted cheap technology, 'vastly increasing' risk of nuclear accident
China "vastly increased" the risk of a nuclear accident by opting for cheap technology which will be 100 years old by the time dozens of its reactors reach the end of their lifespans, according to diplomatic cables from the US embassy in Beijing.
Cables released this week by WikiLeaks highlight the secrecy of the bidding process for power plant contracts, the influence of government lobbying, and potential weaknesses in the management and regulatory oversight of China's fast expanding nuclear sector.
In August, 2008, the embassy noted that China was in the process of building 50 to 60 new nuclear plants by 2020. This target – which has since increased – was a huge business opportunity.
"As the CPR-1000 increases market share, China is assuring that rather than building a fleet of state-of-the-art reactors, they will be burdened with technology that by the end of its lifetime will be 100 years old," reads another cable dated 7 August 2008.
For the past 10 years the CPR-1000 has been the most popular design in China. In 2009, the state news agency Xinhua reported that all but two of the 22 nuclear reactors under construction applied CPR-1000 technology.
The cable suggests this was a dangerous choice: "By bypassing the passive safety technology of the AP1000, which, according to Westinghouse, is 100 times safer than the CPR-1000, China is vastly increasing the aggregate risk of its nuclear power fleet. "
"Passive safety technology" ensures that a reactor will automatically shut down in the event of a disaster. This is what happened when the earthquake struck Fukushima, though the fuel still overheated when the cooling system broke down. Plants without this feature are considered even less safe as they rely on human intervention which can be difficult to provide in a crisis situation.
China says it has updated and improved the technology on which the CPR-1000 is based, but the government recognises that it is less safe than newer models.
Westinghouse Electric Company announced today that its NuCrane Manufacturing LLC (NuCrane) facility in Hutchinson, Minn. has begun shipment of the first AP1000 polar crane destined for China National Nuclear Corporation's (CNNC) Sanmen 1 Nuclear Power Plant currently under construction in Sanmen County, Zhejiang Province, China.
Westinghouse Electric Company, a group company of Toshiba Corporation (TKY:6502), is the world's pioneering nuclear energy company and is a leading supplier of nuclear plant products and technologies to utilities throughout the world. Westinghouse supplied the world's first pressurized water reactor in 1957 in Shippingport, Pa. Today, Westinghouse technology is the basis for approximately one-half of the world's operating nuclear plants, including 60 percent of those in the United States.
you'll see the swimming pool type reservoir on top - now if this isn't compartmentalized on a structural level, quake damage could easily cause leaks, threatening to drain the whole supply prematurely
, which tbh, if you looked closely, is only supposed to cool the inner steel shell, not the core itself via heat exchangers - which you'll have to do to prevent a meltdown. not that you could just dribble water into a pressurized core anyway. ie. afaics, the mechanism is only intended to limit the damage one step short catastrophic release
breeding fuel from fertile elements (U238 and TH232 in this context) allows for a reduction of fissile content (and therefore excess reactivity)
i just can't overlook that there is only a single barrier between contaminated steam and the environment in case of a primary coolant leak, because the concrete shell is perforated to facilitate convective cooling. call it a trade off if you like, maybe they even have ways to shut these ports, although none are shown in the (admittedly crude) diagram.
i also wonder how increased containment pressure would be used to trigger water cooling of the outer shell and how reliable such a mechanism is compared to integrated safeties like part of the ESBWR's emergency cooling system which is online at all times and drains in case of a pressure drop, directly into the core.
all i'm saying is that these passive safeties should be used to provide additional margins,
while it sounds good to have hands-off safeties for 72 hours, i have to wonder how relevant it would be in an actual emergency, since noone can seriously expect an NPP to remain completely unattended for three days.
Originally posted by C0bzz
In existing plants the containment is usually over a meter of steel reinforced concrete with a few millimeters of steel liner on the inside. On the AP1000 the containment has 5cm thick steel and also has a shield building (that can handle a direct airliner hit). I guess you go from two materials making the containment to one material of a lower thickness, but you gain passive safety and don't need to worry about external factors like strong winds because the shield building can handle that.
Also the difference between core melt frequency and core damage frequency is a factor of 10 which is the same as existing reactors, so presumably the containment is about as reliable as existing ones as in both cases 1/10th of core melt incidents result in a large release.
There are three kind of valves on the gravity tank, I presume that they fail open as well.
The point of passive safety is that it happens automatically without any support mechanisms or dependencies required to function. A blackout, diesel pump failure, operational error should not cause a release of radioactive particles. Passive safety is not so the plant can run unattended,