Low-energy ion beams can be effectively used to emulate material damage in nuclear energy reactors. Damages that could take years in a reactor environment could in principle be reproduced in few days using an ion accelerator. An ongoing experimental program at ATLAS led by a collaboration between PHY, MSD and NE, uses fast ion beams for the irradiation of candidate materials [1]. Following irradiation, the materials are analyzed and their robustness and adequacy for nuclear reactor environment is evaluated.

A dedicated ATLAS Material Irradiation Station (AMIS)

As part of the planned ATLAS multi-user upgrade that will add the capability of simultaneously accelerating two ion beams and switching them to different target stations [2], a dedicated irradiation station will be installed following the positive ion injector (PII), which is the first acceleration section of ATLAS delivering ion beams with energies of 1-1.5 MeV/u.

A future eXtreme MATerial research facility (XMAT)

A new extreme material research facility is being considered at Argonne to enable rapid in-situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Advanced Photon Source (APS). The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment.

The Accelerator group of the Physics Division has developed a conceptual design for a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for ²³⁸U⁵⁰⁺ and 1.7 MeV for protons [3]. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz which is one of ATLAS frequencies.

The proposed XMAT facility will be unique in the US and probably in the world by offering fast irradiation and real-time imaging of material damage to allow the design and fabrication of more advanced materials for nuclear energy and other applications. Its development will be a multi-disciplinary effort by accelerator physicists, material scientists and X-ray physicists.

References

1. M. Pellin et al, ​“MeV per nucleon ion irradiation of nuclear materials with high energy synchrotron X-ray characterization”, Journal of Nuclear Materials 472 (2016) 266-271.
2. B. Mustapha et al, ​“The ATLAS multi-user upgrade and potential applications”, Journal of Instrumentation 12 (2017) T12002.
3. S. Kutsaev et al, ​“Heavy ion linear accelerator for radiation damage studies of materials”, Rev. of Sci. Instr. 88 (2017) 033302.