Taiwan should update the assessment of all natural hazards that could affect its nuclear power plants, notably for earthquakes and tsunamis, the European Commission (EC) has recommended.
The recommendation followed a peer review performed by the EC and the European Nuclear Safety Regulators Group (ENSREG) of the stress tests carried out on Taiwanese plants in 2012 by operator Taipower and the Taiwanese nuclear safety regulator, the Atomic Energy Council (AEC).
Overall, the peer review found that standards of safety applied to Taiwanese nuclear power plants "seem to be generally high and to conform in most areas to international state-of-the-art practices." Taiwan currently has three operating nuclear power plants and another one under construction. All four plants were covered by the EC's peer review.
However, the EC recommended that the island should use more modern techniques in identifying earthquake-related hazards for its plants. It suggested that Taiwanese assessments regarding earthquake hazards do not meet current international requirements and do not take into consideration new geological and geophysical data regarding "capable faults in the site vicinity of the Chinshan, Kuosheng and Maanshan plants." Older geological records dating back 10,000 years (and not just tsunami data from 1867, as at present) should be considered. Common standards also need to be applied to all Taiwanese plants as there are currently some variations, said the commission.
"Since some plants are located in close vicinity, combinations of events, including multi-unit and multi-site effects, should be assessed in order to identify potential cliff edge effects and related safety enhancements," the EC's report explained. Alternative emergency control rooms should also be set up at Taiwanese plants, the report said. "Apart from local operating consoles and remote shutdown panels, no alternative emergency control rooms exist that would represent an additional hardened alternative to the main control room," the EC said. In addition, Taipower should set up a strategy to minimise the quantity of contaminated water resulting from an accident. "Evaluating options to create closed cooling circuits could greatly improve plant preparedness," the report read.
Finally, the European Commission recommended that the AEC be more transparent about its decisions.
Deputy director of the AEC's department for nuclear regulations Shin Chang claimed that the review agreed that stress tests in Taiwan had been carried out "by essentially following the specification of the European stress tests." She added: "We have strong commitment in nuclear safety and have been enforcing improvement strategies."
Chang noted: "Currently Taiwanese earthquake hazard assessments are ongoing. The work will surely meet current international requirements and consider new geological and geophysical data regarding the newly identified capable faults in the site vicinity of the Chinshan, Kuosheng and Maanshan plants."
Looking ahead, the AEC will carefully study the peer review and assess whether new AEC guidance for operator Taipower are needed. The AEC plans to invite the Commission and ENSREG to undertake a follow-up visit within three years, according to Chang.
By Carmen Paun and Jens Kastner
for World Nuclear News