- The presented work details the SNEAK-12B experimental program, which is under reevaluation in a joint collaboration of CEA/KIT/Ben-Gurion University. In this work a reevaluation of the SNEAK-12B programs is made with the Serpent 2 code, which enables a detailed study of the presented core. The reevaluation was made utilizing two nuclear data evaluations (JEFF-3.1.1 and JEFF-3.2). The paper provides a complete overview on the benchmark specification and the calculation results for the different configurations. This is followed by a complete sensitivity/uncertainty analysis based on the JEFF-3.2 evaluation, and finished with cross-section adjustment procedure, which was made in order to evaluate the impact of the experimental program on the nuclear data. This work was done in the frame work of new core design and innovative experimental program to be implemented in the new zero power reactor ZEPHYR.