Experimental and Calculation Investigations of the Space-Energy Neutron and Photon Distribution in the Vicinity of Reactor Pressure Vessel and Surveillance Specimen Box of New Type in the WWER-1000 Mock-Up

The radiation field parameters in the vicinity of new type of WWER-1000 surveillance specimens boxes and in RPV simulator have been investigated in the WWER-1000 Mock-up in the reactor LR-0. The neutron and photon spectra have been measured with stilbene cylindrical crystals in the energy range approximately from 0.5 MeV to 10 MeV. The experimental values of integral neutron field parameters (attenuations of integral neutron flux densities between different points of mock-up as well as the spectral indices, i.e., ratios of integral neutron flux densities with different thresholds) were obtained also. The mock-up (LR-0 reactor) power monitoring during measurements was carried out with two fission chambers, one fixed, one moveable axially, so that four orders in power were covered. The experimental data (spectra, attenuation factors, and spectral indices) have been compared with the calculation results. The sensitivity to parameters of calculation model and method was evaluated also.