About 20 employees working in Kaiga Nuclear Power Plant in Uttara Kannada district of Karnataka have suffered minor nuclear radiation after drinking contaminated water in the plant.

The employees working in the first maintenance unit of the plant were treated for increasing level of tritium after they drank water from a water cooler in the operating area on November 24, official sources said on condition of anonymity.

Tritium, also known as Hydrogen-3, is used in research, fusion reactors and neutron generators.

Urine examination of the employees in the unit is done everyday as a matter of routine and during such a test four days ago it was found that the tritium level was more than the normal level. They were taken to the plant hospital in Mallapur and treated immediately, the sources said.

“The contents of the water in the cooler are being investigated,” the sources said.

Scientists carried out immediate checks for radioactivity at the plant site but no leakage was detected, they said. A probe was being carried out to find out how the water in the cooler was contaminated, the sources added.

KAPS-I has been shut down since October 20 for annual maintenance.