Radiation emergency in Mayapuri, Delhi

As per the reports, a Gamma Cell imported in 1968 from Canada, was being used for research at the Delhi University. It was lying unused since 1985 i.e., for the last 25 years. The Cell contained a high-intensity radioactive source, Cobalt-60 with a half life of about 5.3 years. The source is well-shielded inside the cell using lead or depleted uranium as shield material. The source is safe for handling when it is inside the shield. Without shield, it is an open, bare source which can cause severe radiation exposure to people nearby. This is a typical radiation emergency situation, which requires radiation protection experts to manage.

In every 5.3 years, the radioactivity will be reduced by half of the existing activity. The sources lose considerable radioactivity after some years and are called decayed sources (misnomer), the sources still will have enough radioactivity, the exposure to which can be fatal to humans. Such decayed sources are required to be sent to either to the supplier or to the national waste management facility at BARC. Such transfers can be done only after consulting the national regulatory body, Atomic Energy Regulatory Board (AERB) located at Anushaktinagar, Mumbai. In this case, it was just auctioned as metallic scrap material in February this year.

Legally, such radioactive source shall never be disposed off through auction or otherwise to any scrap dealer. All institutions using radioactive sources are required to inform the AERB regarding possession of the sources. AERB is supposed to keep inventory of all the radioactive sources existing with institutions/Universities and in industry. Large numbers of radioactive sources are used in industrial radiography a NDT used in quality control programs.

Gamma cell – Mayapuri incident

Gamma cell (also called gamma irradiator) is used for irradiation of materials to study the effects of radiation. The cell generally contains high energy gamma radiation sources like cobalt-60. The cobal-60 is artificially produced in nuclear reactor by neutron irradiation of Cobalt-59 isotope. The Cobalt-59 is naturally occurring isotope and is not radioactive. Cobalt-60 has a half life of 5.3 years. This only means, in 5.3 years, the radioactive content of the source becomes one-half of the initial radioactivity. As per the decay law, in 2, 3, 4, half lives (in 10.6, 15.9 and 21.2 years), the radioactivity will reduce by one-fourth, one-ninth and one-sixteenth of the initial activity. It will take many more years for the radioactivity to come down to any acceptable, safe levels.

In some news papers, it was reported that the source found in a Mayapuri (Delhi, India) scrap dealer was showing radiation level of 1000 R/h (R is the unit of exposure rate, Roentgen per hour). It is also reported that the gamma cell was bought in 1968. That means the source has decayed by 8 half-lives. The initial dose rate must have been (8x8=64) in the range of 64,000 R/h.

Invariably the gamma cells are accompanied by the operating manuals and the design details. These documents, if available will give details about the number of source pencils and their configuration inside the cell which will vary depending on the required radiation dose for irradiation.

Sources of this high dose levels are never handled openly. They are handled remotely in specially designed and well-shielded enclosures called Hot Cells. The gamma cell is also a well-designed enclosure with the radiation source inside the lead or depleted uranium shield to prevent radiation leakage outside the cell. The design is such that only authorized persons with lock & key arrangement can remotely operate the source for irradiation of sample materials.

IAEA Study on Child Radiation Doses from CT Scans

An international study, conducted by the IAEA, has shown that in some countries children are over-exposed while performing computed tomography (CT) scans. These children are receiving adult-sized radiation doses, although experts have warned against the practice for over a decade.

The study, which was carried out at 128 healthcare facilities in 28 developing countries in Africa, Asia and Eastern Europe, also found great variation in radiation levels and in the frequency of CT scans performed on children under 15 years of age. The study showed that 11 CT centres in six countries were using adult exposure parameters for paediatric patients. This is due to the operator´s lack of awareness and with CT scans it is difficult to detect higher exposures from the image obtained. If the exposure is too high, the image does not deteriorate and in fact, it tends to look better.

This is in contrast to the conventional X-rays. If the exposure is slightly higher, the image goes black indicating that a higher radiation dose is given than required.
(IAEA News)

Some more radioactive sources found in Delhi

Radiation monitoring experts from BARC have detected two more Co-60 sources in a scrap shop in the Mayapuri junk market. In view of the high energy radiations of Co-60 and its potential for causing harm in case of exposures, it is desirable that the authorities seriously look into the causes for the incidents and rectify the same so that there is nuclear-scare amongst the public. Among others, the authorities should also consider:

1. As a matter of requirement, all the scrap yards and metallic scrap shops should have radiation detection systems in place.
2. Import of metallic scrap should be banned.
3. Steel companies also should have radiation monitoring system in place for scrap monitoring before the scrap is processed for melting.
4. Medical management of radiation injuries should be part of curriculum in all the medical colleges.
5. Public awareness regarding radiation and radiation detection should be inculcated amongst para-medical staff and crime detection agencies.

Radioactive source search and recovery – Mayapuri Delhi

Finding a radioactive source in scrap has become a common radiological occurrence world-wide. This is unfortunate because there is no way of knowing that a person is exposed to a radioactive source unless the exposure is severe and clinical changes are detectable in the exposed individuals as in the case of Mayapuri incident. BARC scientists have done a good job of searching and recovering the source in a scrap-yard in the locality. The so-called decayed sources and scraped industrial and medical cameras containing radioactive sources find entry into the scrap yards. This is a global problem and needs to be addressed by the regulators.

India, being a terror-targeted country, stringent monitoring and surveillance programs should be in place at all the scrap entry points like ports and all scrap-yards should be equipped with radiation detection systems. The existing laws governing the handling and disposal of radioactive sources should be enforced strictly to ensure safety of members of the public. The mass media channels should be used to create awareness about the radiation, radiation detection and radiation protection aspects. It is high time, we should wake up!

Health risks of mobile phone towers

Finally, the Maharashtra Government wakes up to the threat of potential health risks posed by the radiofrequency (RF) radiation emitted by the mobile phone towers. The government has appointed a high-level committee of experts to look into the matter and recommend norms for erecting the towers. Radiation protection-dedicated blogs (http://radsafe.blogspot.com and http://icareforyou2007.blogspot.com) and the Mumbai Mirror have been continuously publishing posts/reports asking for regulation on the installation of towers and control on usage of mobile phones by children and others.

Research findings have shown that the radiation is harmful and internationally accepted standards are available for controlling the exposures (see www.radsafetyinfo.com).

It is a good move by the government and the ignorant public is waiting to see how the government tackles the strong lobby of telecom service providers who will oppose the government’s move at all costs.

Nuclear energy and high safety standards

In Indian scenario, as on today, the safety status in nuclear power plants apparently looks good. The Atomic Energy Regulatory Board, the regulator in India publishes detailed annual reports giving all the incidents occurred in the power plants and in other related facilities. Anyone can have access to these reports (www.aerb.gov.in).

However, the news papers keep on publishing insignificant and trivial occurrences, thus causing unnecessary doubts in the minds of a common man. For example: some depleted uranium pieces found with scrap dealer or tritium activity in water cooler at Kaiga, etc. etc. Depleted uranium is used as a shield material in industrial radiography cameras used for Non-Destructive Testing (NDT). Once scrapped, these high density spares are likely to find its way to the scrap dealers. The second incident of tritium must be a deliberate attempt by some staff member to create confusion in the plant. Tritium is the least toxic radioactive material and the limits on intake as tritiated water or as tritium gas are very high. These are some radiological incidents are NOT related to nuclear safety of the power plants and the safety record of the power plants continues to be very satisfactory.

May be, there is some need of enforcing the existing regulations strictly in the plants, and security provisions of the radioactive sources should be augmented in public domain since the sources in sealed form are used in industrial and medical therapy applications. Let us not ignore the immense benefit of radiation in comparison with small amount of risk of remotely possible incidents which are common, and much more in other industries.