Comparison of evaluated nuclear data for neutron irradiation damage calculation in fusion spectra

摘要

The present work analyzes the neutron irradiation damage in fusion applications with different evaluated nuclear data. Comparing with fission reactions, higher quality nuclear data (including the differential cross sections) are required for fusion irradiation damage calculations. Taking the neutron irradiation damage of iron as an example, a 11% difference between JEFF-3.3 and ENDF/B-VIII.0 is found in a First Mirror Unit (FMU) located in the ITER diagnostic first wall, while the differences are within 4% in fission reactors. The deviation of neutron irradiation damage among different nuclear data is much more important for tungsten isotopes. The total damage rates of natural tungsten computed with JEFF-3.1.1, JEFF-3.3, JENDL-4.0, and TENDL-2019 are respectively 55%, 56%, 66%, and 44% larger than the value calculated with ENDF/B-VIII.0 (= FENDL-3.1d in the fast energy region) in an ITER FMU (and 56%, 60%, 69%, and 47% larger in the tungsten divertor). The differences are reduced to smaller than 20% if the recoil energy-angular distributions of the (n,2n) reaction in ENDF/B-VIII.0 are removed. It is noteworthy that the irradiation damage of tungsten is largely underestimated if the atomistic simulation results and the six nuclear data libraries (including FENDL-3.1d) analyzed in the present work are applied.