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Kaiga: Question mark over nuclear safety

December 04, 2009 18:31 IST

To investigate the Kaiga episode, we need an independent committee, composed of external experts, radiation biologists, safety specialists and representatives of workers. We cannot afford to be cavalier about nuclear safety, writes Praful Bidwai.

The poisoning of more than 90 workers with radioactive tritium at the Kaiga nuclear power station is a serious safety violation, which calls for a critical look at India's nuclear power programme. The way the episode came to light, and the manner in which the authorities, from plant managers to the Atomic Energy Regulatory Board, to top officials of the Department of Atomic Energy, responded to it is a disturbing tale in itself.

The tritium ingestion was noticed on November 24 only after its effects had become manifest in abnormal levels of the isotope found in the urine of 92 plant workers, of the 800 tested. The plant managers admitted to the incident only after it caused public concern and the media reported it. Although they called this a "malevolent act", they didn't report it to the police for a week. The police aren't convinced this was the first occurrence of its kind at Kaiga.

We still don't know precisely how and for how long the workers' internal exposure to tritium occurred, what was the concentration of tritium in the water-cooler (which was allegedly deliberately spiked with tritium), and how many people drank the water. All that the Nuclear Power Corporation, which operates the Kaiga reactors, said is that two workers received a dose exceeding the 30 millisievert maximum limit stipulated by the Atomic Energy Regulatory Board. This is a general limit for radiation, not specific to tritium, a highly toxic substance for which different measures such as Curies or Bequerels per litre are usually prescribed the world over.

AERB and DAE officials have denied safety lapses and blamed the mishap on internal 'sabotage' or 'mischief-making' by unidentified employees: these employees, 'it appears', added tritium-contaminated heavy water to a drinking-water cooler. The officials claim the cooler was properly sealed and the 'mischief-maker' poured the tritiated water into it through its 'overflow tube'.

This raises many awkward questions. Did the affected workers involved belong to the Kaiga power reactor? How frequently and rigorously are their urine samples tested? If the testing is not done daily, the tritium ingestion could have occurred many days before it was detected. If so, the heath effects would be far worse than claimed. If, on the other hand, the workers belonged to a special facility to produce tritium for military purposes by separating it from tritiated heavy water -- as some reports suggest -- then the incident points to a grave safety vacuum or violation.

In the second case, only the best-trained and security-cleared employees should have been allowed to extract tritium-containing water, put it into vials and handle or transport it -- and too only under strict supervision. Evidently, this wasn't ensured. In any case, it doesn't make sense to allow anyone to handle a dangerous and expensive material like tritium without stringent oversight. The estimated costs of producing tritium vary from $30,000 (about Rs 13.88 lakh) per gramme in Canada to $100,000 (about Rs 46.27 lakh) in the US. Strategically, tritium is an extremely sensitive material used in nuclear weapons as a booster

The AERB and the DAE are wrong to counterpose 'mischief' by 'disgruntled' employees to safety lapses. Good regulation and sound safety procedures must reckon with the possibility of mischief, irresponsible conduct or sabotage, and prevent or limit harm from them. The possibility that employees' discontent should reach such extremes as deliberately inflicting harm upon their colleagues speaks of a poor working culture and calls for introspection on the DAE's part.

The DAE's hypothesis that a worker inserted the tritium into the water cooler through its overflow tube sounds dubious. Given the weight of the water column inside the overflow tube, the tritium would have to be pumped into it with considerable force. This at minimum would require some planning and prior collection of equipment like pumps.

This needs thorough investigation by an independent body. That body cannot be the AERB. The board is a subsidiary of the Atomic Energy Commission, without its own staff, budget or equipment. The DAE is the operator, planner, licensor, builder and manager of all nuclear projects -- without independent regulation or safety audit. The DAE secretary is also the AEC chairman. The AERB, as former board chairman A Goapalakrishnan puts it, is the DAE's 'lapdog'.

To investigate the Kaiga episode, we need a truly independent committee, composed of external experts, radiation biologists, safety specialists and representatives of workers and citizens liable to be affected by nuclear mishaps. Parliament must demand such a committee which is empowered to examine all the relevant records and practices and recommend compensation to the affected workers and corrective action. The truth about the tritium exposure must be fully established.

The DAE has tried to trivialise the hazards posed by tritium and treated it as a non-toxic substance. But tritium is a beta-ray emitter and can cause extensive, irreversible damage. Scientific studies indicate that tritium in living creatures can produce effects including cancer, genetic defects and developmental abnormalities. It can cause mutations, tumours and cell death.

Tritiated water is associated with significantly decreased weight of brain and genital tract organs in mice and can cause irreversible loss of female germ cells in both mice and monkeys even at low concentrations. Lower doses of tritium can cause more cell death, mutations and chromosome damage per dose than higher doses. Tritium can impart damage which is two or more times greater per dose than either X-rays or gamma rays.

There is no evidence of a threshold for damage from tritium exposure. Even the smallest amount can have negative health impacts. Tritium bound in animal or plant tissue can stay in the body for 10 years or longer. Tritiated water may be cleared from the human body in about 10 days. But if a person lives in an area where tritium contamination continues, s/he can experience chronic exposure. Tritium from tritiated water can become incorporated into the DNA, the molecular basis of heredity for living organisms. DNA is especially sensitive to radiation.

The DAE and AERB have a cavalier attitude to tritium safety. They have failed to evolve adequate exposure standards for tritium, whose maximum dose has been reduced in many countries by about 1,000 times over the past two decades. Physicist and nuclear safety researcher Surendra Gadekar narrates a frightening episode at the DAEs heavy water plant at Rawatbhata in Rajasthan in July 1991: 'Drums of tritiated heavy water were stored in a room that needed a whitewash. Outside labourers were hired to do the whitewash and found that the taps were (as usual) not working. They mixed the lime with the water in the drums, did the whitewash, then cleaned their brushes and faces with the same water and went away. All this without any supervision from plant authorities.'

Says Gadekar: 'It was only later when the radiation counters started screaming that these worthies surmised that their rooms had the costliest whitewash in history and instituted a search for the 'errant' labourers who… decided to remain incognito and suffer the injuries to their health in silence. Since they were only 'casual' outside labourers and since the incident did not cause any ripple in the English language media, the nuclear establishment was able to laugh the matter off.'

The DAE's history is replete with safety breaches, accidents, hundreds of cases of occupational workers' exposure to radiation well in excess of the officially stipulated maximum limits. At least 350 such cases were documented by this writer in 1982 in The Times of India from the Tarapur power station alone. The then DAE secretary H N Sethna didn't deny the overexposure, but blithely declared that it posed no danger to the workers!

DAE accidents include a fire in the turbine room (Narora), collapse of a containment dome -- a concrete shell meant to protect the environment against leaks from the reactor -- during construction (Kaiga), flooding of a reactor building (Kakrapar), and a recent 14-tonne radioactive heavy water spill (Chennai) Not enough is known about the DAE's safety procedures because it operates under a veil of secrecy thanks to the Atomic Energy Act, 1962. This allows it to suppress any information it doesn't wish to disclose. However, what is known about safety lapses in its uranium mines, transportation of nuclear materials and waste storage practices should raise alarm.

These safety failures are compounded by the absence of transparency, independent oversight, safety audit and public accountability. The true social, health-related and environmental costs of nuclear power in India will only be known if the Atomic Energy Act is amended and an independent licensing and safety regulatory agency is created, which reports to Parliament and exercises full authority over the DAE.

Such an agency must formulate transparent rules, procedures and norms on the basis of expert advice and state-of-the-art understanding of the best practices prevalent in the nuclear industry. It must subject them to public debate. It must make a serious environmental impact assessment based on transparent public consultation and hearings before approving a project site. And it must conduct health surveys both before project construction and periodically thereafter. We cannot afford to be cavalier about nuclear safety.

Praful Bidwai