Evaluation of Bias for SCALE 6.1 MAVRIC Sequence Calculation Using Measurement Data of Neutron Flux on Ex-Core Detector

The measured data are sub-channel powers detected from safety channel ex-core detector obtained during Power Ascension Test of initial core of KSNP reactors. MAVRIC sequence is a coupled radiation transport code intended to deal with problems that are too challenging for standard, unbiased Monte Carlo methods with an aid of deterministic discrete ordinates method. The calculation results from MAVRIC sequence are compared to the measured neutron fluxes obtained from operating KSNP reactors. As a preliminary study for activation calculation in reactor primary shield, the calculation bias of MAVRIC sequence of SCALE 6.1 code in transport analysis for a typical reactor model especially in ex-vessel region has been determined by the comparisons with measured data from operating KSNP plants. Evaluated systematic uncertainty of +30% can be considered as calculation margin when applying MAVRIC sequence to activation analysis of concrete primary shield for decommission