An easy way to perform a radiation damage calculation in a complicated geometry

Abstract

With the advent of ITER the need for more and more accurate fusion neutronics analyses increases. The standard software package for these analyses is MCNP, which can be used for three-dimensional radiation transport analyses. Besides the more traditional neutron flux values all kinds of derived parameters are also requested. These include radiation heating and reaction rates. For components receiving a high neutron flux the calculation of radiation damage is an important issue. Usually approximations are made to calculate the radiation damage. In this paper we present a method to calculate radiation damage in a simple yet accurate way without resorting to complicated molecular dynamics simulations. We use detailed continuous-energy damage cross-section data in combination with a modified material specification, which is weighted by the damage cross-section of the isotopes. A theoretical foundation for this approach is given. The data are compared with damage cross-section data from literature, showing a good agreement. It is demonstrated that, without additional effort, a calculation of radiation damage is possible which is completely consistent with the underlying radiation transport calculation. This greatly simplifies these calculations and gives the possibility to calculate of radiation damage as a standard deliverable in ITER analyses.