Deterministic and Monte-Carlo interpretations of the MASURCA BALZAC-SI internal storage SFR experiment and quantification of uncertainties to nuclear data

•The BALZAC-SI experiment, performed in the MASURCA critical mock-up, is analysed.•This experiment models the storage of spent fuels in the neutron shielding of a SFR.•The TRIPOLI4® Monte-Carlo code and the APOLLO3® deterministic code are used.•Several up-to-date nuclear data libraries are used.•Discrepancies up to 20% are obtained with both Monte-Carlo and deterministic codes.•A sensitivity analysis is done in order to understand the observed discrepancies.•Nuclear data uncertainties can explain a part of the obtained discrepancies.•Additional studies are necessary to fully understand these discrepancies.