Chinese nuclear plant experienced a small leak last month, a stakeholder says

www.nytimes.com
June 15, 2010

A fuel rod at a state-owned nuclear power plant in southeastern China last month leaked traces of radioactive iodine into the surrounding cooling fluid, but no radiation escaped the building, a Hong Kong electric utility with a 25% stake in the power plant said Tuesday. The Hong Kong electric utility, CLP Group, said in a statement that the leak was small and fell below international standards requiring reporting as a safety issue. CLP Group's disclosure on Tuesday followed a report about the leak on Radio Free Asia. Chinese state media were silent on the topic.

China plans to build three-quarters of the world's new nuclear power plants in the coming decade as part of a broad effort to diversify its sources of electricity and limit pollution from the burning of fossil fuels. China has not announced accidents in its civilian nuclear power program, and no major cases are known to have occurred. The plant, located on Daya Bay in Shenzhen, adjacent to Hong Kong, continued producing electricity without disruption, CLP Group said. The Security Bureau of the Hong Kong government said that 10 radiation sensors in Hong Kong had not detected any increases since the leak, which occurred on May 23.

The Daya Bay plant uses two loops of fluid in making power. The fluid in one heats as it circulates around the fuel rods, then transfers the heat to water in a second loop of intertwined pipes. The steam produced expands through a turbine, spinning it to generate electricity. The leak occurred when radioactive iodine escaped from at least one of the French-made fuel rods, CLP Group said, adding that an investigation was under way to identify how that happened. The radioactive iodine, a byproduct of splitting uranium atoms, leaked into the fluid surrounding the fuel rods but did not contaminate the water whose steam powers the turbine, CLP Group said.

CLP Group said that the plant -- which is 75% owned by the China Guangdong Nuclear Power Group, one of the country's two rival state-owned nuclear power giants -- had reported the incident to mainland Chinese regulators. But it was not serious enough to be rated on the International Atomic Energy Agency's scale for assessing the seriousness of nuclear safety incidents, the company said.

Radioactive iodine is a serious health concern because it is easily ingested by the body, particularly by children. The United States keeps large numbers of iodine tablets ready in case of a leak because people taking small, daily quantities of iodine by tablet are likely to absorb less radioactive iodine.