GYEONGJU, South Korea (Yonhap News) -- A small amount of coolant leaked from a nuclear power plant under repair earlier this week but there were no reports of injuries, the plant's operator said Tuesday.

Eleven workers were hurriedly evacuated after the leak was reported at the Wolseong nuclear power plant near the southeastern provincial city of Gyeongju shortly after noon on Sunday, the state-run Korea Hydro & Nuclear Power said.

Laboratory tests later found only negligible amounts of radioactive materials in the workers' urine samples, the company said.

The 700,000-kilowatt reactor was under repair at the time of the leak, it said.

The leaked coolant was all collected by Monday and will be reprocessed for reuse, the company said.

The reactor in trouble is one of the five at the Wolseong plant. It has been under repair since Feb. 23 and was scheduled to resume operation on April 1.

South Korea is sensitive to any nuclear accident, especially after the Fukushima nuclear disaster in Japan.

South Korea currently has 23 nuclear reactors in operation and is building several more. It gets about 40 percent of its electricity from nuclear power generation.