Evaluation of core nuclear analysis code system for LMR using measured physics parameters of BFS-73-1 critical assembly

Abstract

As the first stage of the critical experiment plan for developing the Korea Advanced LIquid MEtal Reactor (KALIMER) core design, the basic neutronics characteristics of the BFS-73-1 critical assembly representing a uranium metal fueled benchmark core were investigated. The prediction capability of the core nuclear analysis code system, being developed as a standard analysis system in the KALIMER core design and analysis, has been evaluated against the BFS-73-1 experiment by comparing the calculated results to the measurements. The comparison shows that the effective multiplication factor was overpredicted by 0.3% in the C/E value. The 235U and 238U fission reaction rate distributions were underpredicted within a 2% discrepancy in the core region but appeared to be in poor agreement in the blanket region. The calculated values of spectral indices at the core center and the effective delayed neutron fraction, β eff, agreed with the measured ones within 2% and 1% discrepancies, respectively. The first order perturbation method predicted the sample reactivity worths for 235U, 238U, 239Pu and 10B within 7% but much larger discrepancies existed for the other materials. The calculated Doppler effect showed about an 8% overprediction.