Kakrapar nuclear plant shut down after coolant system develops leak

A rupture in the coolant system of one of the nuclear reactors at Kakrapar, Gujarat, on Friday morning forced the authorities to indefinitely shut down the plant. Multiple sources confirmed that there was no harmful, radioactive leakage and the backup safety mechanisms kicked in.

However, it will be a while before experts can actually get close enough to the plant to investigate what went wrong, given the high temperature at the plant.

“Unit 1 of the Kakrapar Atomic Power Station, which was operating at its rated power, had to be shut down about 9 a.m. today, consequent to a small leak in the Primary Heat Transport (PHT) System. The reactor was shut down as per design provisions,” a statement issued by the site director of the plant, Lalit Kumar Jain, said.

“All safety systems are working as intended. The radioactivity/radiation levels on the plant premises and outside are normal.”

Harikumar S., Secretary of the Atomic Energy Regulatory Board (AERB), told The Hindu that the pressure tubes that had supposedly ruptured were last changed in 2012, as per a planned refurbishing.

“This is a rare event for a functioning plant and it requires a thorough investigation. The plant has considerably cooled down now.” Likening it to the coolant system of a car engine engendering a leak, he said it was the magnitude of the leak that was of concern and it was probably the first time such an incident had occurred in an Indian nuclear power plant.

“Every incident is of immense importance… There is nothing to panic but the magnitude of the coolant system failure is significant,” he said. All of the components that constitute the cooling and backup safety system were indigenously manufactured, he added.

Located in south Gujarat, the Kakrapar atomic power plant consists of two units of pressurised heavy water reactors of 220 MW each.

The first reactor was commissioned in September 1992 and it started commercial production in May 1993.

The second unit was commissioned in January 1995 and began commercial production in September 1995.

The second unit has been shut since July 2015 for maintenance. Friday’s incident means that Unit-1 too will be out of action until it gets clearance from the Atomic Energy Regulatory Board.

“A team of experts from the BARC and another from the Ahmedabad-based Physical Research Laboratory are on the way to the plant,” said Surat Collector Rajendra Kumar.

“Everything within the plant is under control, nobody has been exposed to the leakage and experts are supervising the plant.”

Authoritative sources in the Department of Atomic Energy (DAE) said heavy water leaked in the reactor building of the first unit when a feeder tube in the primary heat removal system gave way.

When the heavy water leaked, the reactor tripped immediately.

“The reactor shut down automatically. We bottled up the reactor building. Everything is under control.”

The first reactor was commissioned in September 1992 and it started commercial production in May 1993.

The second unit was commissioned in January 1995 and began commercial production in September 1995.

The second unit has been shut since July 2015 for maintenance. Friday’s incident means that Unit-1 too will be out of action until it gets clearance from the Atomic Energy Regulatory Board.

‘None exposed to leakage’

“A team of experts from the BARC and another from the Ahmedabad-based Physical Research Laboratory are on the way to the plant,” said Surat Collector Rajendra Kumar.

“Everything within the plant is under control, nobody has been exposed to the leakage and experts are supervising the plant.”

Authoritative sources in the Department of Atomic Energy (DAE) said heavy water leaked in the reactor building of the first unit of the Kakrapar plant when a feeder tube with a small diameter in the primary heat removal system gave way.

When the heavy water leaked, the reactor tripped immediately.

“The reactor shut down automatically. We bottled up the reactor building. Everything is under control.”