KIEV, Ukraine (AP) _ The radiation level inside a Ukrainian nuclear reactor rose above normal when the cooling system malfunctioned, officials said Wednesday.

No increase in radiation was recorded outside the reactor at the Khmelnitskaya plant and none of the staff was injured, said the state atomic energy committee, Goskomatom.

The accident Tuesday night at the plant 170 miles west of Kiev measured as a level one on the seven-level scale of nuclear accidents developed by the International Atomic Energy Agency.

``The temperature in the reactor went up by 10 degrees, which resulted in the slight rise of the radiation level inside the pressurized frame of the reactor,'' said Goskomatom spokesman Mikola Bykeshko.

The staff used the reserve cooling system to bring the reactor's temperature back to normal, and the main system was repaired within three hours, Bykeshko said.

The plant's only reactor has been undergoing scheduled repairs since the middle of April. The VVER-1000 pressurized light water reactor is considered safer than the RBMK-1000 graphite reactor used at the Chernobyl plant.

Level one on the IAEA scale means an accident does not pose radiation danger, but indicates a lack of safety provisions. The 1986 Chernobyl explosion measured seven, and the Three Mile Island accident in 1979 was graded five.