Experience during the monitoring of inactive scrap for the detection of inadvertent presence of radioactivity

The paper describes about the experience gained during the radiation monitoring of inactive scrap generated at various nuclear facilities. This type surveillance is carried out to prevent the spread of radioactivity in public domain and also as requirement by regulatory authorities. The inspection and certification of scrap material from nuclear facilities is a regulatory requirement to ensure that no radioactive material reaches public domain. This paper describes the methodology and experience in detection of radioactivity at inactive Scrap monitoring facility. Inactive scraps (metallic and non metallic) generated from various nuclear facilities of BARC, Trombay is dispatched to Trombay Village Store (TVS) for temporary storage before auction to the public. The monitoring at the facility includes visual inspection and radiation measurement before loading the scrap in the truck. An online PC based monitoring system and portable monitoring instruments in the range (nSv/h-µSv/h) are used to carry out radiation monitoring of inactive scrap loaded in a vehicle. Radioactive source of high activity with potential for serious environmental hazard has not been detected, but few cases of presence of radioactive/contaminated material (MS plate/equipments with low level of 137Cs contamination) have been detected and identified using portable gamma spectrometer. Implementation of strict regulatory measures and radiation monitoring at nuclear facilities can minimize the probability of radioactive material reaching the public domain. The methodology followed for monitoring of inactive scrap is found to be effective even for detection of presence of radioactivity in scrap if any. (author)