The recent incident at the Kaiga Atomic Power Station in Karnataka, where workers drank water that turned out to have been spiked with a radioactive substance, raises disquieting issues. Most of the nuclear power plants in the country that are currently operational, including the one at Kaiga, run on natural uranium. These nuclear reactors also use large quantities of heavy water, whose molecules incorporate a heavier form of hydrogen known as deuterium. With the radiation inside the reactor, some of the deuterium turns into a still heavier form of hydrogen called tritium, which is radioactive. At Kaiga, the first sign of trouble came when a routine urine analysis showed that workers at one of the nuclear plants had ingested tritium. All the nuclear plant’s systems were found to be functioning normally and there had been no heavy water leaks. The tritium was traced to a water cooler in the building that houses the reactor. Small samples of heavy water are drawn daily from the reactor to check its purity. The Atomic Energy Regulatory Board said in a press release that, as the cooler’s water tank was kept locked, “some mischief maker” had added a small quantity of tritiated heavy water to the cooler through its overflow tube.

Officials believe that some insider is the culprit. But even if that turns out to be the case, the incident must be treated with the utmost gravity and the appropriate lessons learnt. There are computerised access control systems to make sure that only authorised individuals enter key areas of the nuclear plant. Close-circuit TV cameras keep watch over activities in critical areas of the reactor building. The tritiated heavy waters samples are also supposed to be guarded. Such surveillance, as it is currently practised, obviously has significant blind spots. How else would even an insider be able to steal a radioactive substance and then introduce it into a water cooler in the reactor building without being detected? The ongoing investigation will hopefully shed light on these issues. But it is not a matter of simply identifying and punishing the guilty individuals. It also goes beyond preventing pilferage of tritiated heavy water in the future. Just a few years ago, an employee at the Waste Immobilisation Plant at Tarapur in Maharashtra was found to have deliberately hidden a tiny bottle containing minute quantities of highly radioactive waste in a chair cushion; three people who later sat on the chair were exposed to low levels of radiation as a result. What is needed now is a thorough review of security procedures at nuclear facilities across the country. The biggest challenge lies in finding ways to guard against insiders bent on making trouble.

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