Core design of prototype Gen-IV Sodium cooled Fast Reactor

- Core Neutronics Design : PGSFR initial core fuel assembly loading layout is revised to use three different enriched fuel assembly for simple fuel loading management. After 4 cycle, equilibrium core is achieved and this is almost twice faster than previous design. For initial/transient/equilibrium core, power distribution, reactivity worth, kinetics parameter, shutdown margin, etc. are analyzed. In these analysis, control assembly's heterogeneity effect is considered in cross section generation. - Core T/H Design : The core T/H design, that both satisfies the design requirements and optimizes the thermal margin, is performed with the PGSFR specific uncertainty evaluation during non-equilibrium cycle. - Core Shielding Design : The changes in PHTS such as the elevation of sodium pool, IHX and DHX, the height of upper shield were applied to PGSFR shielding design. The heterogeneous lower reflector and UIS models were also developed to enhance the fidelity of shielding calculation. The thickness and height of above shield were optimized and finally secondary sodium activity was reduced to 0.283uCi/kg which is below the limit of radiation zone 3. - Topical Report : MC²-3/DIF3D-VARIANT/REBUS-3 SVVRs have been published and used as 'Verification of the Neutronics Design Code System'. 'Uncertainty Evaluation for the Neutronics Design Code System' were completed based on the modeling uncertainty based on the difference between heterogeneous Monte Carlo model and Neutronics Design Code System model, and the cross-section uncertainty based on the statistical analysis of reactor physics experiments. A evaluation method to combine neutronics, core T/H design and fuel performance is developed for thermal design limits. TR was published by verifying numerical methodology and validating with experimental data. By applying general MCNP code, the evaluation of shielding experiment were performed. TR for shielding design code was prepared based on conservative shielding design method