Construction of China's 4G nuclear reactor to start soon
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Superior safety
Compared with second and third generation methods, very few people outside the Chinese nuclear energy community know about fourth generation technology. Fourth generation nuclear plants use high temperature safeguards so, unlike second and third generation plants, they do not need to cool after a leak, Xiamen University's Energy Research Institute Director Li Ning told China Business News on Tuesday. Moreover, fourth generation plants can continue operating at temperatures of thousands of degrees. In fact, high temperatures increase the efficiency of thermoelectric conversion, he said.
"In terms of safety, the fourth generation is clearly superior to the second and third generation technology, because it uses helium coolant's natural convection to keep the reactor under control, even under high temperatures," Li said. "Even when heated for hundreds of hours at temperatures of 1,600 degrees Celsius, the reactor core's coated fuel pellets remain intact."
The pressured water reactors units we see today are massive. In reality, however, the actual reactor itself is only about one thousandth the size of the total unit. Because the reactor is small, it produces huge amounts of heat, making it easy for the core to melt. As a result, it needs large quantities of water to cool it and ensure its safety. However, if the reactor is made sufficiently large, it can radiate heat more easily, meaning no water is necessary to cool it and prevent a reactor core meltdown. Fourth generation technology uses this sort of high temperate gas-cooled reactor methodology.
Some industry insiders point out that the recent Japanese earthquake and ensuing Fukushima nuclear crisis is sounding an alarm bell for Chinese nuclear power construction planners, driving them to redouble efforts to develop and implement fourth generation technology.
However, Li emphasizes that no nuclear power unit is one hundred percent safe. Even fourth generation technology cannot fully guarantee the plant will never suffer a leak. "From a design standpoint, the fourth generation will not allow a core meltdown. Theoretically, it should avoid these sorts of problems, but during actual operation, all kinds of unexpected risks exist. For example, take this Japanese power plant explosion. The core should have closed down and prevented a leak of nuclear material. Unfortunately, the reactor core's meltdown produced a chemical reaction causing an explosion. This is just the sort of thing one cannot predict when designing these plants."
Addressing this issue, Mu Zhanying noted that the Rongcheng plant is only a demonstration of the fourth generation technology. "Only after we build and feel comfortable operating this unit will we consider building two to three additional facilities and exporting the technology to other countries," he said.
"Once it proves itself, we will expand its usage. However, it still needs time to mature. We probably need 10 more years, " he added.
Over the last two years, China has placed increasing importance on expanding nuclear power production, Mu said. However, the approval of new nuclear power projects requires caution, because nuclear power's planning and development demands appropriate equipment and properly trained workers to go with it.
