A review of helium–hydrogen synergistic effects in radiation damage observed in fusion energy steels and an interaction model to guide future understanding

Journal Article · Mon Dec 29 00:00:00 EST 2014 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2014.12.046· OSTI ID:1325878

Marian, Jaime ^[1]; Hoang, Tuan ^[2]; Fluss, Michael ^[3]; Hsiung, Luke L. ^[3]

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1. Univ. of California, Los Angeles, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States)
3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Here, under fusion reactor conditions, large quantities of irradiation defects and transmutation gases are produced per unit time by neutrons, resulting in accelerated degradation of structural candidate ferritic (F) and ferritic/martensitic (F/M) steels. Due to the lack of a suitable fusion neutron testing facility, we must rely on high-dose-rate ion-beam experiments and present-day crude modeling estimates. Of particular interest is the possibility of synergistic (positive feedback) effects on materials properties due to the simultaneous action of He, H, and displacement damage (dpa) during operation. In this paper we discuss the state-of-the-art in terms of the experimental understanding of synergistic effects and carry out simulations of triple-species irradiation under ion-beam conditions using first-of-its-kind modeling techniques. Although, state-of-the-art modeling and simulation is not sufficiently well developed to shed light on the experimental uncertainties, we are able to conclude that it is not clear whether synergistic effects, the evidence of which is still not conclusive, will ultimately play a critical role in material performance under fusion energy conditions. We review here some of the evidence for the synergistic effects of hydrogen in the presence of helium and displacement damage, and also include some recent data from our research. While the experimental results to date suggest possible mechanisms for the observed synergistic effects, it is only with more advanced modeling that we can hope to understand the details underlying the experimental observations. By employing modeling and simulation we propose an interaction model that is qualitatively consistent with experimental observations of dpa/He/H irradiation behavior. Our modeling, the results of which should be helpful to researchers going forward, points to gaps and voids in the current understanding of triple ion-beam irradiation effects (displacement damage produced simultaneously with helium and hydrogen implantation) and the synergistic effects of hydrogen.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 1325878
• Alternate ID(s): OSTI ID: 1246592
• Report Number(s): LLNL-JRNL-694369
• Journal Information: Journal of Nuclear Materials, Vol. 462, Issue C; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE