FLOW CHARACTERISTICS OF THE DECONTAMINATION PROCESS FOR NUCLEAR POWER STATIONS USING DEKOZ-PG I INSTALLATION

Abstract

The DEKOZ-PG I apparatus is utilised for the circulation of decontaminant fluids. It is equipped with a propeller pump with unidirectional operation. An assessment of the process technology concluded that the flow direction of the decontaminant fluids should be reversible by simply switching the drive motor revolutions between clockwise and anti-clockwise modes. This should result in a uniform cleansing of the steam generator walls. In order to fulfil the above requirement, a new impeller had to be designed. The new design was based on information relating to the existing data: n; (pump speed), Q; (volume flow rate) and H; (delivery head) as well as on measurements taken during a visit to the actual site. The new design had to be based on an impeller system with blades that are symmetrical both in axial and in cross direction. This should ensure the proper functioning of the unit irrespective of the direction of drive motor rotation.