Computation of full energy peak efficiency for nuclear power plant radioactive plume using remote scintillation gamma-ray spectrometry

A method of full energy peak efficiency estimation in the space around scintillation detector, including the presence of a collimator, has been developed. It is based on a mathematical convolution of the experimental results with the following data extrapolation. The efficiency data showed the average uncertainty less than 10%. Software to calculate integral efficiency for nuclear power plant plume was elaborated. The paper also provides results of nuclear power plant plume height estimation by analysis of the spectral data. - Highlights: • Spatial calibration of NaI(Tl) for estimation NPP plume radioactivity is developed. • Mathematical convolution of the experimental results is used. • The efficiency calibration data have the average uncertainty less than 10%. • Procedure for estimation of plume altitude from spectral data is proposed. • A software for calculation of NPP plume integral efficiency is developed.