Concerns have been raised about China nuclear plants' safety following the radiation leak accident in Japan. As China's first commercial nuclear station, expert said Daya Bay plant has taken many protection meatures to prevent from the accidents.

Advanced technology

Pu Jilong, members of Special Committee of nuclear power in China said the Daya Bay nuclear power plant was built with advanced technology. He said the Daya Bay nuclear station is the third generation of nuclear plant built in 1990s, while the one is Japan was built in late 1960s-70s and used older reactors. The Daya Bay nuclear power plant, however, was built in the 1990s in line with IAEA's new standard.

The Daya Bay plant, using pressurized water reactors, uses pressurized water to carry away the heat generated from the reactors to the steam generators. In order to cope with the pressure, the reactors' protective layers are at least twice to the thickness of those in the Fukushima plant, which uses boiling water reactors.

Cooling systems

The Fukushima Nuclear Plant has only one cooling system, which makes use of reactor heat to raise steam directly for power generation. "In the case of venting, the steam vented may necessarily release radioactive products," said Professor C.F. Lee, a member of the Chinese Academy of Engineering.

The Daya Bay nuclear power plant has two cooling systems, one cooling system uses water under pressure to transfer reactor heat to an adjoining but separate secondary cooling system to raise steam for power generation. Therefore, the steam generated from the reactor bears no radioactive materials, so even if steam leaks, it will not convey radioactive materials.

The Fukushima Nuclear Plant has no effective deployment of back up equipment. When the tsunami flooded the plant and destroyed diesel generators, there was no power to run the reactor's cooling systems, overheating caused partial fuel meltdowns at the reactors.

"The Daya Bay nuclear power plant has three sets of back-up feedwater pumps to support reactor residual heat removal, with two driven by electricity and the remaining one driven by the steam generated from the secondary cooling system," Professor C.F. Lee said.

Another issue related to the topic of nuclear accidents, is the geological stability of the land on which the Daya Bay plant was constructed. Geologically, the site's surrounding area does not contain any deep faults, and no earthquake activity above 7 on the Richter scale had been experienced in over 1,000 years.

Based on this geological survey, Daya Bay's plant was designed and constructed to withstand an earthquake at the 8 level.

In addition, the sea around the area is only about 20- 30 meter deep and it is unlikely to deliver a tsunami, according to Pu.  

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