Applications of heavy ion linear accelerator for studies of radiation effects in nuclear fuel and structural materials

Abstract

Several existing ion irradiation facilities in the US are being used for accelerated testing of materials to support the DOE-NE mission related to investigation of nuclear materials behavior under irradiation. However, each facility has its limitations that can affect data interpretation and comparisons to radiation damage effects induced by neutron irradiations. For example, existing facilities can provide ion species with several MeV energies for irradiation of structural materials that can cause radiation damage away from the surface. However, the width of the damage zone can limit the interpretation of the damage phenomena. Meanwhile, those energies will produce limited damage, as well as a narrow damage zone in fuel materials, impacting their applicability to study radiation effects in fuel materials. Other facilities can perform irradiations with proton beams at a few MeV energy and produce uniform damage in a sample similar to neutron damage, but the dose achieved can be insufficient, especially for nuclear fuel materials studies. The unique large-scale user facility, the Argonne Tandem Linac Accelerator System (ATLAS), is capable of producing high-energy heavy ions (up to 100 MeV level, or > 1 MeV/u) which are suitable for irradiation effects studies in materials. Compared with other conventional ion accelerators, the ATLAS high-energy heavy ion beam has two outstanding advantages in simulating radiation damage: (1) the ion species and energies match those of nuclear fission products so that the ATLAS heavy ion beams can replicate the damage of in-pile-irradiated nuclear fuel materials, which can reach 1000’s of displacements per atom (dpa); (2) the high-energy heavy ion beam creates a deep damage region, minimizing the surface effects that conventional ion irradiation experiments can suffer. In addition, high-energy ion beams can be used to simulate damage in structural materials, where it will also have the advantage of producing wide damage zones free from added interstitials. An overview of recent use of high energy heavy ion irradiation at ATLAS to study irradiation effects in nuclear fuel and structural materials is presented here.