Lessons from Kaiga
The tritium poisoning episode highlights grave safety lapses and the urgent need for an independent nuclear regulator.
by Praful Bidwai
THE poisoning of workers at the Kaiga power station with tritium is another black mark in the none-too-bright record of the Department of Atomic Energy (DAE). The number affected was variously stated – 35 to 55 by the plant management soon after the episode was noticed on November 24, 65 in initial media reports, 92 by Minister of State Prithviraj Chauhan on December 3, and 250 by Kaiga township residents.
The number is likely to be high if the management’s claim about the source of tritium poisoning is right. The water cooler it has identified is one of eight reportedly used in the nuclear complex.
Close to 4,000 people work in the Kaiga facility. The episode is extremely worrisome because tritium is a highly toxic isotope of hydrogen, internal exposure to which causes grievous harm. Because water containing tritium is chemically identical to normal water, it can infiltrate cells in the human body.
The Atomic Energy Regulatory Board (AERB), charged with safety regulation in nuclear installations, has disclosed no significant information other than that the tritium poisoning came to light only after its effects had become manifest in abnormal levels of the isotope in the urine of plant workers. Such urine checks are reportedly not conducted daily on all the workers. So it is possible, indeed likely, that some workers were exposed to tritium well before they were tested.
No details have been revealed of doses of tritium received and their duration, except that two workers still recorded high tritium levels on November 29, which correspond to an excess over the maximum permissible dose of radiation for a year (30 millisieverts).
How the AERB arrived at this number remains a mystery. Tritium concentration per litre is usually calculated in curies or becquerels, which measure the number of disintegrations per second, while radiation exposure is measured in roentgens or sieverts, a different unit. At any rate, tritium decays relatively rapidly. So precisely when the measurements were taken – on November 24, 25 or 29 – would matter a great deal.
The doses reported for three workers by a magazine (Outlook) journalist who saw their records are way above the maximum permissible limit (100 microcuries per litre) for concentrations in urine. In two cases, they were 1,940 and 1,695 microcuries on November 25. In the third case, the level was 862 on November 26. This necessitates serious investigation and long-term monitoring. The Health Physics Unit should have checked the urine and blood of all the plant workers, including casual and contract workers. But it ran urine checks on only 800 of the workers. Nothing indicates that it is monitoring all the acknowledged affected 92 workers.
It would be dangerously wrong to treat the tritium ingestion episode as a one-time crisis with no lasting effects. But the AERB is playing down the hazards of tritium exposure. Globally, tritium is increasingly recognised as much more dangerous than thought earlier.
The maximum permissible concentration (MPC) of tritium has been brought down in countries such as France and Britain from 10,000 becquerels/litre to just 20 or 100 Bq/l. The AERB sticks to the high limits. Worse, Indian operators often work in environments with concentrations that are hundreds of multiples of MPCs, without protective plastic suits. Many years ago, this writer noted signs showing a “600-MPCs” level at the Rajasthan Atomic Power Station. The workers said that it was too hot in the desert summer to wear an impermeable plastic suit. TRITIUM HAZARDS
Tritium hazards are serious. Tritium, a beta-ray emitter, can cause extensive, irreversible damage in living creatures including cancer, genetic defects and developmental abnormalities. 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 chromosomal damage per unit than higher doses. Damage from tritium is two or more times greater per dose than from X-rays or gamma rays.
There is no threshold for damage from tritium exposure. Even the smallest amount can cause harm. Tritium bound in animal or plant tissue can stay in the body for 10 years or longer. Tritiated water may be cleared from the body in about 10 days. But if a person lives in an area where tritium contamination continues, she/he can experience chronic exposure. Under chronic exposure, tritium can become incorporated into human DNA (deoxyribonucleic acid), the molecular code of life.
This, at minimum, warrants long-term monitoring of all workers who are exposed to tritium at India’s 15 heavy water reactors. Such monitoring must go beyond urine checks and include numerous tests to detect long-term effects including chromosomal damage, cancer and genetic deformities. The AERB does not conduct such tests.
SHROUDED IN MYSTERY
The Kaiga episode remains shrouded in mystery. It is astounding in the first place that workers are allowed to extract tritiated water into vials and handle and transport it without stringent supervision.
Tritium is much costlier than gold. The cost of production is estimated at $30,000 to $100,000 a gram in the United States and Canada. It is also a strategic material, which is used as a yield-booster or trigger in both fission and hydrogen bombs. It simply makes no sense to permit unsupervised handling of such a material by workers other than those who are highly trained and security-cleared, but nevertheless must at all times be under a watchful eye.
There is no credible account from the management or the AERB of how the alleged “saboteur” or “mischief-maker” inserted tritium vials into the water cooler through its overflow pipe. Given the weight of the water column inside the pipe, the tritium would have had to be forcibly pumped into it. This would have required planning and equipment like pumps.
Alternatively, someone would have had to open the cooler’s lid, which is apparently fastened by heavy nuts and bolts. Removing it would have needed elaborate planning, procurement of equipment and manoeuvres, which would have been noticed.
SAFETY LAPSE OR SABOTAGE?
In either case, the saboteur’s work either went unnoticed or was executed with the complicity/collusion of the supervisory and watch-and-ward staff. Both possibilities speak of serious safety lapses. The DAE’s plea that there was no safety lapse and that it was helpless in the face of sabotage is fundamentally wrong.
Good regulation and sound safety procedures must reckon with the possibility of mischief, irresponsible conduct or sabotage, and prevent or limit harm from them.
This raises a larger issue. The DAE has had a series of accidents and mishaps, and a long history of violations of its own safety norms. It has exposed hundreds of workers to radiation well in excess of the officially stipulated maximum limits.
At least 350 such cases from Tarapur alone were documented by this writer in 1982 in The Times of India. H.N. Sethna, the then DAE Secretary, did not deny the overexposure but blithely declared that it posed no danger.
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 (Rajasthan), and a 14-tonne radioactive heavy water spill (Chennai).
The DAE operates under a veil of secrecy, thanks to the Atomic Energy Act, 1962. This allows it to suppress any information it wants.
These safety failures are compounded by the absence of transparency, independent oversight, safety audit and accountability. The AERB is a subsidiary of the Atomic Energy Commission, without its own staff, budget or equipment. The DAE operates, plans, licenses, builds and manages all nuclear projects – without independent regulation or safety audit. The DAE Secretary is also the AEC Chairman.
This unacceptable arrangement encourages lack of accountability and irresponsible conduct. Both the DAE and the AERB are set in their ways and have proved resistant to reform.
Their handling of safety issues follows a clear pattern: suppress inconvenient facts until they cause public concern and the media report them; deny that there is a serious problem and minimise the health damage caused; deflect attention from design failures and the generic problems of nuclear technology; and rely increasingly on casual workers who have no rights and who cannot demand information on safety.
There is an urgent need to amend the Atomic Energy Act and establish an independent licensing and safety regulatory agency, which reports to Parliament and exercises authority over the DAE. Such an agency must formulate rules, procedures and norms on the basis of 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.
However, going by the Civil Nuclear Liability Bill that is likely to be tabled soon, which limits compensation for nuclear mishaps to pitifully low levels, the government seems inclined to go the other way. It must be brought to heel.