Exposure Attributable to Activities of Authorised Practices
Informing the Board about the extent of radiation exposure in Namibia is a key and central mandate of the NRPA. There are different sources of radiation exposures leading to radiation exposure of the workers and the public.
Workers and the public are liable to incur radiation exposure above normal background level due to the activities of authorised practises. The NRPA has a programme in place to ensure that workers are subject to routine assessment of the radiation exposure while the exposure of others workers and that of the public is determined on the basis of workplace and area monitoring.
The purpose of the monitoring programmes are (i) to demonstrating compliance with the regulatory limit (20mSv/a for workers and 1mSva for members of the public); (ii) establishing baseline data and reference levels to optimise the exposure; (iii) confirming good working practices; (iv) providing information about conditions in the workplace; (v) providing information about the magnitude of potential risks as a result of exposure resulting from these practices.
Exposure Attributable to Natural Occuring Radioactive Material
Natural exposures are excluded from regulation, but these need to be assessed in order to evaluate if there is any significant risk involved, or if intervention is in any case justified to protect people against perceived risk; or to advise on the land management practices. Exposures to natural sources are normally considered as chronic exposure and, if necessary, are subject to intervention. Exposure situations requiring remedial action to reduce or avert chronic exposure include (i) natural exposure, such as exposure emanating from terrestrial, cosmic and internal radiation in homes and workplaces or (ii) exposure to radioactive residue from the past.
The Authority has embarked upon a programme to establish the extent of natural exposure for the purpose of providing information on the need for action or intervention should this need be justified. This programme cover all inhabitable areas, with the first data collection initiated in Windhoek, Otjiwarongo, Tsumeb and some areas in the Uranium Province. The current focus of data collection is external radiation exposure due to gamma and radon with its progeny.