Nearly 10 days after one of the units of Kakrapar Atomic Power Station (KAPS) in Tapi was shut down due to leak in the Primary Heat Transport (PHT) system, authorities have begun probe to "find the cause of the failure". Authorities at the KAPS said that the 220MW unit-I that was shut down on March 11 will restart only after the probe is over.
One of the two 220MW units of KAPS was shut down after leakage of heavy water, which is used for cooling off the nuclear reactor core. A temporary site emergency was also declared as a measure of safety. However, the officials then said there was no radioactive leak and that all the workers were safe.
In a statement issued on 23-03-2016, KAPS site director L K Jain said, "The investigation will now be carried out to find the cause of the failure. The unit will restart after the completion of the investigation, inspection of relevant components and equipment and implementation of corrective actions, in line with the stage-wise clearances of the Atomic Energy Regulatory Board."
The statement added that the 220MW Pressurized Heavy Water Reactor (PHWR) core comprises of 306 coolant channels made of Zirconium-Niobium alloy, each of which houses 12 (nuclear) fuel bundles. After the affected coolant channel was isolated and the leak was arrested, the fuel bundles from the identified channel were removed (defueled).
"The bundles have been inspected and are found to be intact," the statement added.
The coolant flows through the channels, transferring the heat from the fuel to the steam generator to produce steam for driving the turbine to produce electricity.
"No worker involved in the operations was exposed to any undue radiation. The radiological conditions remain normal and cooling is being maintained in all the remaining channels. All the systems are operating normally and the unit is in a safe shutdown state," the statement added.