Kakrapar n-reactor's leaking coolant channel to be sent to lab

The next major step after plugging the leak in the first 220 MW nuclear power reactor at Gujarat's Kakrapar Atomic Power Station (KAPS) is to send the affected channel for testing in a lab and also arriving at the cause of leak, said the atomic sector regulator.

On the morning of March 11, the first reactor at KAPS belonging to Nuclear Power Corporation of India Ltd. (NPCIL) shut down automatically following leakage of heavy water from its coolant channel.

The leak was plugged ten days later.

"The NPCIL has to carry out necessary investigations and submit a report to us. The company has to get our permission before cutting the affected channel and taking it to a lab for testing," S.A. Bhardwaj, chairman, Atomic Energy Regulatory Board (AERB), told IANS over phone from Mumbai on Friday.

Bhardwaj's earlier stint at NPCIL as its director (technical) and his understanding of the systems have come in very handy in dealing with the problem, nuclear industry officials told IANS.

Queried whether NPCIL can restart the reactor with or without new coolant channel, he said: "Both options are possible. The affected channel is low power one."

As the reactor has 306 channels and each channel has 12 fuel bundles, the absence of one channel and a bundle will not cut down the power output if the reactor is restarted, he said.

Now the NPCIL has the take the call as it has to complete its probe into the leakage of heavy water and the kind of damage that the coolant channel has suffered.

"First NPCIL has to tell us what had happened. Then we will start our activity," he added.

As the affected channel is in the reactor's core area, it has to be removed carefully due to radiation and transported to a lab following the laid down procedures.

According to industry officials, the whole process may take some months.

The affected channel needs radiation shielding. The equipments have to be brought in and set up for removing the affected channel.

Most probably, the coolant channel will be sent to Bhabha Atomic Research Centre (BARC) in Mumbai for study.

"The lessons to be learnt will be known after the investigations have been completed on the affected coolant channel. Then necessary action that needs to be taken will be taken," S. Harikumar, AERB secretary, told IANS.

The coolant channel at the affected reactor was changed only in 2011.

At present, KAPS Unit 1 is in cold shut-down state and all the plant systems are functioning normally, AERB said in a statement on Tuesday.

India's atomic power plant operator NPCIL has two 220 MW units at KAPS. The second unit is under maintenance shut-down since July 2015.

Interestingly, AERB was much more open in its communications about the incident as compared to NPCIL, whose top corporate officials were not available for comments or clarifications.

"We have to tell people about the actual situation and the safety aspects," Bhardwaj said.