Track Detector Measurements in RPV of WWER-1000 Mock-Up in the LR-0 Reactor

Abstract

The fission rates measurements were carried out with track detectors in the WWER-1000 mock-up assembled in the experimental reactor LR-0. The 238U and 236U isotopes with the fission energy thresholds approximately 1.5 MeV and 0.8 MeV, respectively, were used. The tracks were counted by means of a photomicroscope with a digital camera controlled by a PC with corresponding software. The fission rate ratio of 236U and 238U has been evaluated in different measuring points as well as the fast neutron fluxes attenuation factors. The correction for photo fission has been included. The results obtained with different techniques were compared: the fast flux above 0.5 MeV was measured absolutely with a stilbene detector.