Carbon contamination, its consequences and its mitigation in ion-simulation of neutron-induced swelling of structural metals

Conference · Sat Oct 07 04:00:00 EDT 2017

DOI:https://doi.org/10.1007/978-3-030-04639-2_44· OSTI ID:1570355

Shao, Lin ^[1]; Gigax, Jonathan ^[1]; Kim, Hyosim ^[1]; Garner, Frank ^[1]; Wang, Jing ^[2]; Toloczko, Mychailo B. ^[2]

---

1. Texas A & M University
2. BATTELLE (PACIFIC NW LAB)

Neutron-induced swelling in austenitic and ferritic steels is sensitive to the carbon level in the steel, as well as its distribution in matrix or precipitates. It has recently become known that ion-irradiation to high dpa levels leads to a progressive ion-beam-induced increase in carbon concentration and precipitation within the ion range, with concurrent reductions in void swelling. This neutron-atypical phenomenon imperils the credibility of ion simulation for light water reactor applications. A series of experiments involving pure iron and a structural alloy HT9, was conducted to identify the source and distribution of injected carbon. It was found that negatively-charged carbon atoms are entrained in the self-ion beam by a Coulomb drag effect, and thereby delivered at low drift energy to the irradiated surface, followed by ion-beam-mixing and diffusion. A technique for filtering out contaminants, especially carbon, oxygen and nitrogen, was developed and resulted in higher, more neutron-relevant swelling levels than achieved without filtering.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1570355
• Report Number(s): PNNL-SA-127786
• Country of Publication: Switzerland
• Language: English