ABSTRACT
There are differences and inconsistencies to some degree in the radioactive contamination control level of personnel′s body surface availiable in many national standards, thus puzzling the users. Therefore, it is proposed to compare the applicable scope, conditions and differences between relevant national standards, and combine with similar clinical nuclear medicine standards of radiological protection content to presevent recommendations on the contamination control level that should be correctly applied in an event of nuclear and radiological emergency. Based on the discussion of similar standards, the contaminated personnel with α of 0.04-10 Bq/cm 2 and β of 0.4-100 Bq/cm 2 are advised to be treated in the institutions with higher than secondary medical insititution. Both α econtamination control levels less than 0.04 Bq/cm 2 and β levels less than 0.4 Bq/cm 2 could be achivable, if fully decontaminated.
ABSTRACT
Because of the complex buildings, the wind flow and the pollution diffusion will be affected in the microscale such as urban neighborhood or the site of facility, the straight Gaussian plume model will not be available. Based on the Reynolds-Averaged Naiver-Stokes(RANS) method which was used to calculate the wind field with the Lagrange particle random walking model, the radioactive pollution diffusion model and microscale radiation environmental impact assessment software system were developed. This system can be used in the factory or city streets and other similar conditions for simulating radioactive pollutants diffusion behavior. The development of the system will provide technical tools for the microscale radiation environmental impact assessment in the future.
ABSTRACT
Objective To develop a new software system that cau directly display the predicted results on an electronic map,in order to get a directly perceived understanding of the affected areas of nuclear and radiological terrorism events in city areas.Methods Three scenarios of events including spreading radioactive materials, dirty bomb attack,and explosion or arson attacks on the radiation facilities were assumed.Gaussian diffusion model was employed to predict the spread and deposition of radioactive pollutants,and both the internal and external doses were estimated for the representative person by using the corresponding dose conversion factors.Through integration of the computing system and Mapinfo geographic information system(GIS),the predicted results were visually displayed on the electronic maps of a city.Results The new software system could visually display the predicted results on the electronic map of a city, and the predicted results were consistent with those calculated by the similar software Hotspot(R)The deviation between this system and Hotspot was less than 0.2 km for predicted isoplethic curves of dose rate downwind.Conclusions The newly developed software system is of the practical value in predicting the effects of nuclear and radiological terrorism events in city areas.