By IANS,
New Delhi : Nuclear Power Corporation of India Limited (NPCIL) is reviewing its processes and procedures after the contamination of a water cooler with radioactive Tritium in Kaiga nuclear plant, Minister of State in Prime Minister’s Office Prithviraj Chavan said Thursday.
“The processes, procedures and human performance aspects of all stations of NPCIL are being reviewed again to carry out reinforcements as appropriate,” Chavan said in a statement in Lok Sabha.
The security agencies are still investigating log books and CCTV footage to zero-in on the culprits behind the contamination of a water cooler at Kaiga Atomic Power Station in Karnataka, that left 92 persons exposed to relatively high doses of tritium.
Chavan said the interim report on the incident had found that “some heavy water containing tritium was deliberately added to the drinking water cooler with malafide intent.”
“As regards the investigation, the local and central agencies are at work and the evidence like log books, close circuit TV footage, analysis of water samples etc are being used to ascertain the facts,” Chavan told parliament.
He said that the contamination was first detected Nov 24, when the results of routine urine tests of employees working in the service building showed higher than normal traces of tritium.
After checks at all plant systems found radiation levels to be normal, the source of the contamination was zeroed in on a water cooler located in the service building.
The service building is separate from the reactor building and consists of electricial, mechanical and instrumentation shops, chemical labs, health physics unit, decontamination centre, clothing cribs and change rooms.
Out of the 800 employees in the vicinity of the cooler, 92 had “higher than normal” tritium content in their urine samples.
Chavan said that the human body usually brings down the level of excess tritium through natural processes like urination, perspiration and excretion.
All the affected, except two, have now returned to work. The two employees have tritium presence in their body “which can increase their extrapolated annual radiation exposure to marginally exceed the specified limit of 30 millisievert per year”.
“However, even in the case of these two persons further medical management will bring down their potential radiation exposure to less than the AERB specified limit in a short time,” said Chavan.
NPCIL had formed a committee under the chief superintendent, whose interim report had described the motive as “mischief” by an insider.
A first information report (FIR) has been filed Dec 1 at the local Mallapur police station.