5-26 Measurement of Leakage Neutron Spectra from 238U Slabs with D-T Neutrons and Validation of Nuclear Evaluation Data Libraries

The accurate nuclear data for 238U are of great importance in the design of the Accelerator-Driven Sub-critical Systems(ADS).An integral experiment was carried out at China Institute of Atomic Energy(CIAE)to measure the neutron spectra from pure Uranium-238 slabs with 14.8 MeV D-T neutrons using Time-of-Flight(TOF)Method.The leakage neutron spectra at 60?and 120?have been measured for different sizes of the slabs(10 cm×10 cm×2 cm,10 cm×10 cm×5 cm,and 10 cm×10 cm×11 cm).The simulations with MCNP-4C code coupled with different nuclear evaluation data libraries(ENDF/B-VII.1,JENDL-4.0,CENDL-3.1,JEFF-3.2 and TENDL-2015)have been performed.Fig.1 shows the comparison of measured and calculated leakage neutron energy spectra for 14.8 MeV neutron on the Uranium-238 sample in size of 10 cm×10 cm×2 cm.It is found that JENDL-4.0 fitted the experimental data best.