Neutron and gamma spectrometry in the research reactor LR-0

Complex measurement system for full-scale VVER models (mock-ups), created in the research reactor LR-0, is discussed. Fast neutron (energy from 0.5 to 10 MeV) and gamma spectra are measured in several representative points of mock-ups by two-parameter spectrometer with cylindrical stilbene scintillation detectors. Measurements in the thermal and epithermal neutron region are carried out with activation method using broad set of activation monitors and with ³He(n,p) counter. Activation measurements with threshold fast neutron detectors enlarge also proton-recoil spectra measurements, such measurements are carried out especially in cases, when spectrometer cannot be put in the necessary position. The core fission rate distribution is obtained by means of gamma-scanning of fuel pins. The low noise precise power (flux density) monitoring system, independent of operation control system, was developed in the LR-0 reactor for mock-up experiments.