An atomic power station is broadly divided into the “nuclear island”, where steam is produced in the steam generator by nuclear fission in a reactor, and a “conventional island”, where steam supplied from the nuclear island is used to drive the turbine-generator to produce electricity.
The snag-hit 1,000-MWe unit-one of the Kudankulam Nuclear Power Project, the country’s first nuclear reactor unit built with Russian assistance, is learnt to have been briefly shut down to attend to a leak noticed in the conventional system of the station recently.
An atomic power station is broadly divided into the “nuclear island”, where steam is produced in the steam generator by nuclear fission in a reactor, and a “conventional island”, where steam supplied from the nuclear island is used to drive the turbine-generator to produce electricity. The leak is ascertained to be in the conventional island of the Kudankulam-I unit. The date when the leak was detected could not be ascertained.
To a specific query on the leak, a government official involved in the exercise said the Russian VVER-1000 reactor unit was restarted after “necessary rectification”. The incident, officials said, had “no radiological safety implications” and therefore did not call for any safety and security audit.
The incident-prone Unit 1 of the atomic power project had earlier faced an outage in October 2013, when it was test synchronised with the southern grid. The unit did not hold for long and tripped immediately after being connected to the grid. Then, less than a year later, in September 2014, the unit had to be shut down on account of an unforeseen “mechanical malfunction” to a vital component of the turbine. The latest leak is the third in a series of major incidents that have forced a shutdown.
“The first unit of the Kudankulam plant operated for about twenty months since its grid connection before it was taken for planned shutdown on June 24, 2015 for refueling. This was the first planned shutdown after a long operation and required a detailed surveillance and maintenance. Apart from refueling, completing all the surveillance tests as per the technical specifications, mandatory checks on various components as per the manufacturer’s recommendation and rectification of the deficiencies identified during the inspection were carried out during the shutdown,” and official said.
After the latest shutdown, the unit is learnt to have been connected back to the grid on January 30, 2016 by the operator — state-owned Nuclear Power Corporation of India Ltd, according to latest reports.
In light of the latest incident, NPCIL officials said they are simultaneously working on getting the first unit up and running while also ensuring that a recurrence of such an event in the second 1,000 MWe unit of Kudankulam, which is currently under commissioning, is prevented.
The Unit 1 of the KKNPP, which was synchronised to the grid in October, 2013, was shutdown on the afternoon of September 26, 2014 on account of “certain observations in its turbine during its operation”. The turbine had, subsequently, been opened and its various components have been inspected.