Oscillations in primary system and neutron flux at Vandellos NPP

Research concerning neutron noise analysis has been performed at the Vandellos nuclear plant, a 1040 MWe Three Loop Westinghouse PWR. It covers: an analysis of the response of the nuclear power induced by pressure, temperature and inlet flow sinusoidal oscillations of low and medium frequencies (up to 5 Hz), with SIMTRAN, a coupled neutronic-thermohydraulic code developed for PWR core analysis; development of a model of the ex-core detectors and experimental validation of the model with neutron noise analysis data; nuclear response when two-phase flow occurs in some channels, as produced by crude deposition. Several important conclusions were obtained such as the Moderator Temperature Coefficient from neutron noise data at low frequencies. (author)