COMPARATIVE STUDY OF CASMO-5/SIMULATE-5 AND nTRACER FOR EPR CORE ANALYSES

摘要

The 3-D pin-by-pin core analysis by means of deterministic methods can be performed with two main approaches: the two-step approach, being the combined calculation of a lattice code for the nuclear data preparation and the nodal code for the full calculation, or the direct approach for solving the whole core in one-step up to the sub-pin level detail. In this paper, solutions of pin-cells, lattices and of the EPR core quadrant obtained in two-step with CASMO-5 / SIMULATE-5 serve as reference for an assessment of the one-step solution obtained with the code nTRACER, developed at Seoul National University. This study is relevant in the framework of validation and verification of nTRACER for the simulation of Generation Ⅲ LWR cores. The results represent a starting point to study the different modelling of the core analyses, in particular related to the adopted nuclear libraries and the approximations applied to the neutronics. The results put in evidence some difference between the fuel and gadolinium depletion models of CASMO-5 / SIMULATES and nTRACER, in particular when comparing the pin power distributions at the lattice and at the core level. This emphasizes the need of further investigations to explain the findings of the current comparison.