Cost Optimisation by Capping the Tailing Ponds of the U-Mine in Hungary

Full text: The restoration of the tailing ponds by covering with proper soil layers is in the last phase of the planning and the work has to be started in summer of this year. The general viewpoints of the remediation of the environment are defined by limitation of the external dose rate, the radon-efflux and the radioactive concentrations in soil layers. From the new local data and information derived during the last year determinations our task was to assess the averted dose and introduce a cost-benefit analysis for restoration of the tailing pond I. According to the recent assessments the covering by a thickness of 30-50 cm soil layer to avoid dusting and for planting vegetation might be perfect for radiation protection. Depending on the thickness of soil layer used for capping the contaminated area the cost of unit collective dose averted (the alpha-value) has been assessed to 20-200 thousand USD person-1Sv-1. These values are higher than the used averaged ones in nuclear safety. Due to the high uncertainties prognosed the declaration of the end point got from cost-benefit analysis involves a high incompetence and might be less safe for the future. In addition to the viewpoints of radiation protection the effects of the chemical - mainly heavy metal - contaminants to the water base are to be taken into consideration. Therefore the covering by 1-2 m soils is planned. (author)