ABSTRACT
@#<b>Objective</b> To investigate the radionuclide radium-226 and natural uranium content in the main agricultural products around a decommissioned uranium tailings pondand to determine the radioactivity level in the food around the tailings pond. <b>Methods</b> From 2017 to 2021, several samples of rice and beans were collected in the surrounding area of the tailings pond for five consecutive years, and the concentrations of radium-226 and natural uranium were measured by a high-purity germanium gamma spectrometer. The annual accumulated effective dose of internal exposure caused by radium-226 ingested through local standard human diet was estimated by the indirect method. <b>Results</b> The detection rate of natural uranium in rice was 96.0%, and the detection rate of radium-226 was 74.0%; the detection rate of natural uranium in beans was 96.7%, and the detection rate of radium-226 was 73.3%. The annual accumulated effective dose caused by radium-226 ingested through diet was about 170.22 μSv/a in surrounding residents. <b>Conclusion</b> The concentrations of radium-226 and natural uranium in the main agricultural products around the tailings pond are within the limit of the national standard. By comparing with the research results in related fields in China, the radiation effects caused by radium-226 ingested through dieton the residents around the tailings pond are acceptable.
ABSTRACT
RESUMEN Debido al riesgo que representa el empleo del Ra-226, a nivel internacional se ha recomendado suspender la producción y uso de fuentes radiactivas selladas de este radionúclido. Consecuente con esto, las fuentes de Ra-226 en Cuba fueron recogidas, caracterizadas y acondicionadas. El trabajo describe los aspectos operacionales y de seguridad relacionados con el acondicionamiento de las fuentes radiactivas de Ra-226, para lo cual se requirió de una autorización de la Autoridad Reguladora, otorgada en forma de un Permiso Especial. Una evaluación radiológica de todas las operaciones, el informe de seguridad, así como el plan de emergencia se elaboraron y aprobaron antes de las operaciones. Se estableció un sistema integral de gestión de la calidad que demostró la confiabilidad del trabajo. Como resultado de estas operaciones, se encapsularon y acondicionaron 188,5 GBq de Ra-226 contenidos en diferentes tipos de fuentes radiactivas (agujas y tubos de braquiterapia, fuentes de control, etc.). Las cápsulas con las fuentes se acondicionaron para su almacenamiento prolongado dentro de cinco bultos, de manera que se puedan recuperar.
ABSTRACT The production and use of Ra-226 sealed sources was internationally recommended to be halted for health and safety reasons. Consequently, all Ra-226 sources in Cuba were collected, characterized and conditioned. The paper describes the safety and operational aspects related to the Ra-226 conditioning. For this, a Special Permission was granted by the Regulatory Body, as required. A radiological assessment, a safety report as well as an emergency plan were prepared and approved before the operations. The work was accomplished with due reliability following an established comprehensive Quality Management System. As a result of these operations, 188.5 GBq of Ra-226, contained in different types of radiation sources (brachytherapy needles and tubes, standard sources for calibration, etc.) were encapsulated and conditioned. The capsules with the sources were conditioned in a retrievable form within fi ve waste packages intended for long term storage.
ABSTRACT
We studied the natural radioactivity distribution of an α-emitting radionuclide, 226Ra in water, sediment and biota (plankton, weed, snail, bivalve, prawn and fish) of Cauvery river ecosystem extending a stretch of 95 km. The dissolved 226Ra concentration in river water ranged from 0·82mBq.I-1 to l 06mBq.l-1 (mean: 0·93mBq.l-1) and the activity in river sediments from 4·7Bq.kg-1 to 6·9Bq.Kg-1 (mean: 5·6Bq.kgg-1 dry wt.). The 226Ra activity levels in the biota were within a narrow range from below detection limit to 3·80 Bq.kg-1 (wet wt). Generally higher 226Ra concentrations are observed in the shells and bones of aquatic organisms than in their tissues and muscles. The concentration factors (CFs) of 226Ra for the biotic components ranged from ~ 101 to ~ 103. The significance of 226Ra activity in the abiotic and biotic components of Cauvery river are discussed.