The Fourth Nuclear Power Plant’s raw water reservoir was built on a rock formation and has a tiltmeter and water level monitoring system to ensure its safety, the Atomic Energy Council (AEC) said yesterday.
The council’s comment came in response to a report in Sunday’s Chinese-language Liberty Times (the Taipei Times’ sister paper) that quoted Yenliao Anti-Nuclear Self-Help Association secretary-general Yang Mu-huo (楊木火) as saying the reservoir was built on an unstable formation and could collapse in a mudslide.
The paper said Yang had accused the council of falsely claiming that the formation is stable and that there was no need to worry about it “lacking carrying capacity or liquefaction,” in a report it prepared for an independent peer review team from EU last year.
Yang said a survey report by an engineering consultancy company on the geology of the raw water reservoir site in 2010, commissioned by Taiwan Power Co (Taipower), said the location consisted of “sandstone and laminated sand-shale, fresh and slightly weathered,” and that other geologists have said the formation was a dip slope and prone to weathering.
Atomic Energy Council Deputy Minister Chou Yuan-ching (周源卿) and Nuclear Regulation Department director Chen Yi-pin (陳宜彬) said that the raw water reservoir and the reactor were both built on a solid rock formation.
The council’s report said the original design included an upper reservoir capable of holding 48,000 tonnes of water and a lower reservoir that could hold 72,000 tonnes, but the lower reservoir plan was dropped because that water could be replaced with water provided by a desalination plant, so the weight that the formation bears has been vastly reduced.
“Rock formation” is a generic term it used in the report, but the council had asked professional engineers to assess the land formation to ensure its safety, council officials said, adding that so far, data collected from monitoring equipment have shown no irregular situations at the site.
Soil and Water Conservation Bureau official Chen Chung-kuang (陳重光) said assessment committee members did notice that the reservoir was to be built on a dip slope and they had asked Taipower to be more concerned about safety issues.
Taipower had submitted a list of its response measures if weathering of the reservoir does occur.