Evaluation of the efficiency of operation of a mechanical, high-temperature and high-pressure filter in NPP Temelín.

The primary circuit with the VVER1000{--}320V reactor installed in the nuclear power plant Temelín represents a world-unique technology in terms of reduction of concentration of corrosion products and activated corrosion products by means of mechanical, high-temperature and high-pressure filters. The technology uses continual filtration and its main advantage is cleaning of the primary coolant at operating parameters, i.e. without any adjustments of pressure and temperature of the filtered coolant. The filter is made of especially treated titanium, whose spongy form improves the required interception of undissolved corrosion products and activated corrosion products on its surface. It contributes to limitation of formation of radiation fields and it favorably affects reduction of the effective dose received by the plant{\crq}s operating personnel. In my thesis I have monitored behavior of the corrosion products and activated corrosion products intercepted on the mechanical, high-temperature and high-pressure filters. In the evaluation I have focused on efficiency of operation of one of the selected filters in case of changes in physicochemical parameters in the primary circuit during reactor shutdown and on determination of a potential release of corrosion products and activated corrosion products back into the primary coolant and resulting deterioration of a radiation situation in the proximity of the technological equipment before refueling