Experimental Evaluation of Neutron Spectra in the Irradiation Fields of a Typical Material Test Research Reactor

Neutron energy spectra at different regions inside and around the core of Pakistan Research Reactor-1 (PARR-1), a typical swimming pool type material test research reactor, have been evaluated. The method of multiple foil activation was used together with the adjustment codes MSITER and SANDBP to determine the experimentally measured spectra. The pre-information required by the adjustment codes was obtained through modeling the core and its surroundings in three-dimensions and the use of the transport code WIMS-D/4 and the diffusion code CITATION. The input spectrum covariance information required by MSITER code was also calculated from the CITATION output. Comparison between calculated and adjusted spectra shows good agreement. Integral parameters derived from the adjusted spectra, which includes flux densities over different energy regions and predicted reaction rates were evaluated and compared for the different regions.