SEOUL, South Korea (AP) _ Dozens of angry residents protested today after the government said radioactive water had leaked from a nuclear power plant near their rural village.

Authorities said the leak Monday at one of three reactors at a plant on the southeast coast had been negligible, but villagers said they did not trust state safety controls.

About 30 villagers picketed the plant overnight, demanding a thorough review of safety arrangements at the plant in Wolsung, 190 miles southeast of the capital, Seoul.

``They always say 'no problem,' but how can we trust them?,'' the Yonhap News Agency quoted villager Yoo Chong-ku as saying. ``We'll fight against building more plants.''

Three Canadian-made reactors are operational at Wolsung, and a fourth is under construction. Authorities plan to build two more there.

Villagers were especially angry that the leak was not reported until Tuesday, a day after it happened. The government said, though, that the leak was so insignificant it was not legally required to report it immediately.

In Seoul, 30 environmentalists demonstrated outside the main government building, demanding the government scrap plans to build more nuclear power plants.

``Nuclear means death,'' read one demonstrator's sign.

About 12 gallons of slightly radioactive ``heavy water,'' used in the pumps as a coolant, leaked inside the plant while two workers were performing scheduled maintenance on a pump. No radiation escaped the plant, which at the time was not operating, officials said.

``Heavy water'' behaves like ordinary water, but contains a heavier version of hydrogen. It is not naturally radioactive, but as it circulates in pipes it picks up traces of radioactive metals.

Officials said 22 state power workers had been exposed to low levels of radiation and were sent home Monday. They were all working today, but three were assigned temporarily to clerical duties.

Government officials said the amount of radiation from the leak was equal to four X-rays.

The Korean accident drew special attention because of last week's accident at Japan's Tokaimura uranium processing plant, northeast of Tokyo. In that accident, at least 49 people were contaminated, three of them critically.