Measurement and analysis of neutron leakage spectrum in depleted Uranium-Polyethylene Mock-up

•The measurement of neutron leakage spectra in Depleted Uranium-Polyethylene Mock-up was conducted with DT neutron.•The measured spectra were compared with calculation with MCNP code and ENDF/BVI.5 library.•The calculations agreed well with the experimental ones within experimental uncertainties.•The discrepancy is found in differential neutron flux and also in the ratios of integrated neutron flux.