Calculation and experimental validation of ¹²⁷I transmutation rate in Xi’an pulsed reactor

In order to develop the research on 129I transmutation in the thermal reactor, 127I target was irradiated in Xian pulsed reactor(XAPR) to explore the condition for experiment in XAPR. The Monte Carlo method was used in the calculation of 127I target transmutation rate, and the results were compared with the experimental data. The NJOY software was used to generate 127I ace format neutron cross section at XAPR operating temperature based on ENDF/B VII.0 library. New cross section was compared with old ENDF/B VI library and developed in the unresolved resonance region. MCNP was used to modify the 127I cross section of ORIGEN2 by adopting a new cross section, then transmutation of 127I target was calculated to analyze changes of transmutation rate and nuclides, also the influence of neutron spectrum and irradiating time on transmutation was studied. The CINDER90 software, a depletion mode of MCNPX, was also used to model the transmutation condition, the analytical result was consistent with ORIGEN2, but was a little different from the experimental data (2%-3% error) because of the deviation from the MCNP model in neutron flux calculation.