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.