A smoke detection alarm appeared in the control room of Unit 3 yesterday around 4.30 a.m. following which the 220 MWe nuclear power plant was shut down, the Nuclear Power Corporation said in a statement here.
"On inspection of the respective area, it has been found that there was nothing abnormal," Station Director J P Gupta said.
As an abundant precaution, the unit was shut down, he said.
The nuclear plant operator said routine surveillance tests were planned for Unit-3 before May, when the plant was to be shut down for a couple of weeks.
"Having the unit in shut down state, decision is taken to utilise this opportunity and carry out these tests now itself," the NPCIL said.
After completion of these surveillance tests, it is planned to bring back KGS Unit-3 online, by Apr 17, it said.
KGS Unit 3 began commercial operations on May 6, 2007.
The surveillance tests are carried out at nuclear plants once every two years.
The Kaiga site, in Uttar Kannada District of Karnataka, has four units of 220 MW each.
At present Unit-1, 2 and 4 are operating safely and generating about 560 MWe.
All the four nuclear reactors at Kaiga are Pressurised Heavy Water Reactors and powered by indigenous fuel.
India has 20 nuclear plants under operation which have a total installed capacity to generate 4780 MW power.