Methods of measuring specific radioactivity of deposits without sampling in the primary circuit of NPP with water-cooled and water-moderated reactor

A method has been developed and tested for determining the spesific activity of deposits in the first loop in a nuclear power plant without sampling in order to supplement the information on the specific surface activity determined by using the sampling method. The measurements are carried out by means of a Ge(Li)-spectrometer. The new method makes it possible to determine the specific activity of deposits on the inner surfaces of straight sections in the first loop pipeline and the contribution to γ-radiation dose in the point of detecting radionuclides which are present in the deposits. Data are presented which are obtained in testing the method during a scheduled preventive repair of the 4-th unit in Novovoronezhskaya nuclear power plant