Irradiation of structure material in spallation neutron sources.

Abstract

In principle, intense spallation neutron sources can be used not only to irradiate materials (e.g. window materials) and to validate different target geometries/concepts, but also to irradiate structural materials (samples, pins or even full assemblies) in order to characterize their behavior under irradiation (in a fast neutron field). However, a question arises concerning the ''representativity'' of such irradiations to reproduce the conditions encountered in a typical fast reactor. The present paper documents an investigation aimed at understanding phenomena related to the representativity of an irradiation using an intense spallation source, with regards to neutron damage and Helium production. Two different designs of a spallation neutron source are considered. The first is an Intense Spallation Neutron Source (ISNS) proposed at CEA, France as a potential irradiation tool. The second is one of the current models for the TMT (Target for Material Testing) of the ADTF (Accelerator Driven Test Facility) program. In our calculations we used the MCNPX Version 2.1.5 Monte Carlo code