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Nuclear power plants safe despite report of fault danger: Taipower

2011/09/16 19:58:06

Taipei, Sept. 16 (CNA) State-owned Taiwan Power Co. (Taipower) gave assurances Friday that Taiwan's first and second nuclear power plants in northern Taiwan were safe after local media reported that the area could be vulnerable to a major earthquake.

Taipower Vice President Hsu Hwai-chiung said that even an earthquake with seismic intensity of seven, the highest on Taiwan's seven-tier scale and never before experienced in Taiwan, the two nuclear power plants would still be intact.

"But the priority now is to reinforce the piping system to ensure that water could be sent to the reactors within one hour of a disaster triggered by an earthquake so that they could be shut down safely,"Hsu said.

He was responding to misgivings about the Sanchiao Fault located on the northwestern part of Taipei Basin after a recent survey found it to be at least 80 kilometers, and possibly even 120 kilometers, long, far longer than the previously estimated 40 kilometers.

According to National Taiwan University professor Chen Wen-shan, if a complete dislocation of the fault occurred, it could result in a magnitude 7.5 to 7.8 earthquake.

Taiwan has grown more sensitive to the potential impact of earthquakes on nuclear power facilities after a massive earthquake and tsunami triggered a nuclear meltdown at the Fukushima Daiichi plant in Japan in mid-March, resulting in the release of large amounts of radioactive substances.

Hsu said the piping lines at the first nuclear power plant, located in Shihmen in New Taipei seven kilometers away from the fault, were designed to withstand a "peak ground acceleration" of 0.5G.

If during an assessment on the piping system it is found that the piping cannot meet the standard, the pipes will be replaced or stronger supports will be used.

The second nuclear power plant, located at Wanli, New Taipei five kilometers away from the fault, has set a goal of withstanding a peak ground acceleration of between 0.5G and 0.6G.

The highest level of seismic intensity on Taiwan's seven-tier intensity scale (a 7), generally covers peak ground accelerations greater than 0.4G.

Magnitude is the measurement used to quantify the force of an earthquake at its epicenter, while the intensity refers to the amount of ground motion in a particular area during an temblor.

Hsu stressed that the assessment report on strengthening the piping system would be completed by the end of the year and any necessary work to strengthen the lines would begin early next year.

Though the piping may be vulnerable, Hsu said the containment buildings of the plants' nuclear reactors would have no problem withstanding peak ground acceleration of over 1G.

Even if hit by a massive earthquake like the one that occurred in Japan, the main bodies of the first and second nuclear power plants would have no problems, the Taipower executive said.

Taipower may be looking to fortify its nuclear plants, but one expert said that the chances of a complete dislocation of the Sanchiao fault was minimal.

Dr. Chu Hao-tsu, senior geologist of the Division of Active Tectonics of the Central Geological Survey, said the fault was mainly comprised of three segments.

Because they all have different geological characteristics and crust thickness and might not even be connected, Chu said a dislocation of the magnitude reported was highly unlikely.

(By Lin Shu-yuan and Lilian Wu)