ZPPR-LMFR-EXP-010: Criticality and Sodium Void Worth Measurements in ZPPR-12

The ZPPR-12 experiments conducted by Argonne National Laboratory were designed to study sodium void worth, cell heterogeneity, and neutron streaming. The small core made it possible to conduct sodium void and neutron streaming experiments over the entire core. The simple, clean, single-zone core had no internal structures such as internal blankets or control rods to affect measurements or complicate interpretation of experimental results. Criticality and selected sodium void worth measurements were evaluated for ZPPR-12, and a detailed uncertainty analysis was performed for the measurements chosen for the benchmark. Highly detailed as-built models were developed for all configurations selected for the benchmark. A simplified RZ model was also created for the criticality benchmark. MCNP5 calculations with ENDF/B-VII.0 data for the benchmark models show generally good agreement between calculated and benchmark values for k_eff and sodium void worth.