MCOR – Monte Carlo depletion code for reference LWR calculations

The MCOR (MCnp-kORigen) code system is a Monte Carlo based depletion system for reference fuel assembly and core calculations. The MCOR code is designed as an interfacing code that provides depletion capability to the LANL Monte Carlo code by coupling two codes: MCNP5 with the AREVA NP depletion code, KORIGEN. The physical quality of both codes is unchanged.The MCOR code system has been maintained and continuously enhanced since it was initially developed and validated. The verification of the coupling was made by evaluating the MCOR code against similar sophisticated code systems like MONTEBURNS, OCTOPUS and TRIPOLI-PEPIN. After its validation, the MCOR code has been further improved with important features.The MCOR code presents several valuable capabilities such as: (a) a predictor–corrector depletion algorithm, (b) utilization of KORIGEN as the depletion module, (c) individual depletion calculation of each burnup zone (no burnup zone grouping is required, which is particularly important for the modeling of gadolinium rings), and (d) on-line burnup cross-section generation by the Monte Carlo calculation for 88 isotopes and usage of the KORIGEN libraries for PWR and BWR typical spectra for the remaining isotopes. Besides the just mentioned capabilities, the MCOR code newest enhancements focus on the possibility of executing the MCNP5 calculation in sequential or parallel mode, a user-friendly automatic re-start capability, a modification of the burnup step size evaluation, and a post-processor and test-matrix, just to name the most important.The article describes the capabilities of the MCOR code system; from its design and development to its latest improvements and further ameliorations. Additionally, several interesting studies performed with MCOR are explained; its validation against MONTEBURNS, OCTOPUS and TRIPOLI-PEPIN; sensitivity studies with different voids and cross-section libraries; detailed comparison against measurement. Finally, the MCOR is used as a reference tool for benchmarking deterministic codes on the example of qualification of the spectral codes (APOLLO2-A and CASMO-4).

Research highlights
► Introduction of a reference Monte Carlo based depletion code with extended capabilities.
► Verification and validation results for MCOR.
► Utilization of MCOR for benchmarking deterministic lattice physics (spectral) codes.