Effective delayed neutron fraction and prompt neutron lifetime of Tehran research reactor

Computer codes Wims-D4 and Citation used for calculations of effective delayed neutron fractions βeff and prompt neutron lifetime (Λ) for both HEU and LEU fuel elements of the Tehran research reactor (TRR). Calculations have been performed for two states of the cold clean and hot core configuration. Calculated beta effective of LEU fuel were compared with the measured value and HEU values were compared with the Safety Analysis Report (SAR) of original HEU Fuel. Also the ratios of (βeff)i/(βeff)core, the input data for the reactivity accident analysis are included in the calculations.