The unit was under outage since June 25 afternoon due to control circuit malfunction, said Power System Operation Corporation Ltd (Posco).
The unit most probably would restart generation on Tuesday, a senior official told IANS.
In May only, the unit was shut down due to water and steam leakage. It was reconnected to the grid several days later.
India’s atomic power plant operator, NPCIL has two 1,000 MW nuclear power plants at the KNPP built with Russian equipment.
The first unit was shut down on April 13, for annual maintenance and refuelling, a process that would take around two months.
Every year, one third of the reactor’s 163 fuel assemblies, or 54 assemblies, would be replaced.
This was the second refuelling cycle for Unit 1.