Kaiga incident: Wake up call or tempest in teapot?

December 03, 2009 11:55 am | Updated November 17, 2021 07:06 am IST - Bangalore

A view of the Kaiga atomic plant. File photo: Special Arrangement

A view of the Kaiga atomic plant. File photo: Special Arrangement

Whoever spiked the water cooler in the Kaiga atomic plant with radioactive tritium on Nov. 24 has not been original.

A simple Google search will reveal that the incident is a replay of what happened in 1990 at the Point Lepreau Nuclear Generating Station in Canada.

Reports then said that an employee at the Canadian station obtained about “half a cup” of heavy water from the primary heat transport loop of the nuclear reactor and loaded it into a drink dispenser in the employee canteen.

Eight workers drank some of the contaminated water. The incident was discovered when they began leaving bioassay urine samples with elevated tritium levels.

The media then reported that the episode was intended to be a “practical joke” whereby the affected employees would be required to give urine samples daily for several days!

The Canadian incident was dismissed as a prank and forgotten because it happened prior to 9/11 and 26/11.

Only an ongoing enquiry will tell if the Kaiga incident is the handiwork of a prankster or a “malevolent” act as described by Indian science minister Prithviraj Chavan — or just a plain mistake that has been blown out of proportion.

Nataraja Sarma, retired nuclear physicist and author of the book “Nuclear Power in India” says it could be just a human error — not uncommon at the Bhabha Atomic Research Centre (BARC). He points out that in the 1980s a vast area in the BARC campus got contaminated by radioactive effluents accidentally discharged from the plutonium plant and the soil had to be decontaminated.

In another incident, scrap metal in Mumbai’s “chor” (thieves) bazaar that was found radioactive was traced to the plutonium plant at BARC. A worker had sold some discarded plant parts. K.S. Parthasarathy, former secretary of the Atomic Energy Regulatory Board told IANS he is aware of a case when a worker actually drank some heavy water containing tritium, in the hope he would get a few days off from work. “He was crazy.”

Tritium is the radioactive isotope of hydrogen but the beta radiation emitted by it is of such low energy it cannot even penetrate the human skin. In other words tritium can cause harm only if it enters the body through food or water but its intake must be in large amounts to pose a significant health risk.

Though tritium has a long a radiological half-life (12.3 years) its biological half life — time it takes for half of the activity to be physically removed from the body — is about 10 days which can be shortened to 2-3 days by drinking a lot of fluid.

Some tritium is naturally formed in the upper atmosphere by cosmic rays. The air also contains tritium left behind by atmospheric weapons testing between 1954 and 1962. But most tritium in the environment today is discharged from Kaiga-type reactors that use heavy water as moderator and coolant.

Heavy water is chemically the same as regular (light) water, but with the two hydrogen atoms replaced with atoms of deuterium — another isotope of hydrogen.

During reactor operation, deuterium in heavy water is activated by fission neutrons to form tritium. It is an important material in nuclear weapon design for boosted fission weapons and also has civilian applications — for instance in watch dials that glow in the dark. If not recovered from the used heavy water, tritium is discharged from reactors in its elemental form as a gas through stacks or in the form of tritiated water into the lakes and the sea.

Irrespective of how tritium entered the Kaiga water cooler, the incident highlights the need for vigilance in nuclear plants, says Mr. Parthasarathy. “Traditionally we have been thinking of securing nuclear plants from earthquakes and tsunami but the Kaiga incident has added another dimension to it.”

A retired director of one of the nuclear stations, who does not want to be named, agrees.

“Security today means checking handbags and inspecting vehicles and vigilance is all about who takes bribe,” he said. “Our security at this level is good but is unprepared to deal with potential threats from scientific staff.” A nuclear reactor has several hotspots and tampering with any of these can cause a radioactive accident a lot more severe than the trivial incident at the water cooler, he said.

“Scrutiny of staff is totally missing in our power stations,” he warned, adding that this calls for urgent attention considering that hundreds of new jobs will be created in the coming years with the projected expansion of India’s nuclear programme.

“At present our plants are guarded by persons supplied by the Central Industrial Security Force (CISF) and they take orders from their own boss in Hyderabad or Delhi and not from the station director,” he said. “The nuclear plants should have their own security staff with some training in reactor operation.”

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