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To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B4C) and stainless-steel (SS). The influence of the existence of carbon on the B4C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B4C-SS samples, a new layer was formed between B4C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe2B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

Molecular beam epitaxy (MBE) grown Cu(In1−x,Gax)Se2 (CIGS) thin films were sulfurized at temperatures of 450–550 °C for 30 min in a 10% H2S–N2 mixture gas. The micro-roughness together with the S diffusion in the CIGS surfaces increased with increasing sulfurization temperature. Both near-band-edge PL intensity and decay time of the CIGS absorber layer enhanced after sulfurization. PL sub-peak around 80 meV below the main peak almost disappeared after sulfurization above 500 °C, which is expected due to the occupation of Se vacancies (Vse) with S. The open-circuit voltage (Voc), hence conversion efficiency, improved after sulfurization. The photovoltaic performance of the solar cells was consistent with PL intensity. Moreover, it is found for the first time from the SIMS analysis that the Cu atoms were depleted at the surface of CIGS layer after sulfurization, which could result in the improved Voc. [ABSTRACT FROM AUTHOR]