Long term radiological impact of a uranium mine restoration

Abstract

During the 1990s, many uranium mines were closed as consequence of low prices of this mineral It was due to a decrease in the demand for uranium and an increase in the overall supply. The resulting was a further complicated implementation of sites restorations. This report deals with one of the relevant aspects of the Radiological Protection scope: the evaluation of the long term radiological impact in the population due to the uranium mine restoration activities for the uranium mine sited in Saelices el Chico (Salamanca, Spain). These restoration activities have basically consisted of recovering the original site by filling the old open pits with the material stockpiled in the waste dumps. The main problems associated with this material include radon release and particles emission. The strategy used to solve this problem has been covered these structures with a layer with beds of clay material rock, waste material and a cover tree. The pathways considered for the radiological impact have been: i) Inhalation; ii) Ingestion of contaminated water, milk, vegetables and meat, iii) External exposure from clouds immersion, grounds concentrations and direct gamma radiation. Three computer codes have been used with the object of evaluating the above-mentioned impact. Two of them are well-known NRC (Nuclear Regulatory Commission) codes: RESRAD 6.30 and MILDOS-AREA. We have also applied DOEFLURA, developed in ENUSA [1, 2, 3]. Four scenarios have been studied: Resident Farmer Scenario, Resident scenario, Livestock pasture scenario and Forest scenario. Estimation of radioactive doses for the member of the public in the different scenarios has been calculated with this programme. A period of 3500 years from now has been studied.