Recovery of lost radioactive sources from Coovum river

While discharging its regulatory function, the Atomic Energy Regulatory Board (AERB)  did encounter a  few ticklish problems to handle; often they caught the attention  of the press and the public.

On September 23, 1993, Chennai police received an FIR on the theft of three radioactive sources. They consisted of   two americium-beryllium  (Am-Be) neutron sources of strength 684.5 GBq and 18.5 GBq and one caesium-137 (Cs-137) source of strength 55.5 GBq. They  were allegedly  stolen from the premises of a foreign company based in India, engaged  by Oil & Natural Gas Commission (ONGC) for oil well-logging  operations. The authorization to import these sources was issued by BARC to ONGC in January, 1990.

Preliminary investigations indicated that the company which was  expected to keep three high activity, long half-life sources in safe  and secure custody had not complied with this obligation. ONGC,  the party to whom import authorization was issued, had also failed  to oversee the operations to ensure the security of these sources. In  view of this, AERB ensured by a directive that the foreign company  suspended all its well logging operations using radioactive sources  in India.

AERB mobilized  several teams of scientists  to survey all  potential areas where the miscreants could have thrown or hid these  sources, extensively covering in this process over 450 km of roads in the city and surroundings. Police inquiries eventually indicated that  the sources were lying in a slushy area in the Coovum river bed within  Madras city limits.

Specialists from the Atomic Energy Regulatory Board (AERB), Bhabha Atomic Research Centre (BARC), Oil and  Natural Gas Commission (ONGC), Larsen & Toubro (L&T), Madras  and the Indian Institute of Technology (IIT), Madras deliberated  on various options to recover the lost sources safely. The sources  were finally recovered intact after erecting a coffer dam around the region in which the sources were lying, to allow local de-watering, and after a prolonged and tedious ‘fishing’ operation.

 There were  instances in India and elsewhere in which such sources were lost in  an irrecoverable manner either in the oil well itself or in areas such as  sea beds. There are standard practices to manage such incidents.

After this event, AERB did an extensive study of the issues involved  in such operations and prepared a comprehensive document on the  safety requirements for well logging operations. The Board instituted additional measures to ensure safety of such sources.

Four workers who stole the sources from the premises of the company were convicted up to four years imprisonment. One of them was the approved Radiological Safety Officer (RSO) of the company. He felt annoyed with the company for an unexpected transfer. Aggrieved by it, he organized the theft. The workers carried the sources unshielded in a scooter. Each of them drove the scooter for a fixed distance thereby sharing  the radiation dose for the entire operation!


About ksparthasarathy

I am a former Secretary of the Atomic Energy Regulatory Board. I am a former Raja Ramanna Fellow in the Department of Atomic Energy. Free lance journalism is my hobby
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